Delivering Assistive Technology Services to the Consumer

Quantitative and Qualitative Measurement.

Information gathered by the ATP throughout the assistive technology intervention can be by either quantitative measurement or qualitative measurement. The philosophies of qualitative measures and quantitative measures are quite different. Quantitative measures assign a number to an attribute, trait, or characteristic (Nunnally and Bernstein, 1994). The assumption of quantitative measures is that the construct of interest can be measured in some meaningful way. For example, a test can be constructed that measures the joint range of motion (the construct) that an individual has available to control a computer access device. Joint range is expressed as degrees of motion and a common understanding exists regarding what is meant when a specific joint range of motion is described. Here the construct can be assigned a number that is meaningful to individuals using and interpreting the test. Alternatively, a test can be constructed that intends to measure boredom. It is possible to develop a scale and have individuals rate their boredom on a four-point scale (for example). But what does a score of 4 mean on such a scale? We can assign a number on a scale but it is difficult to interpret the meaning of that number.

Qualitative assessments assume that each individual has a different experience and that it is important to provide the opportunity to capture that experience. There is no attempt to measure a particular construct. Rather, the purpose is to describe and understand the user’s experience with the technology. Qualitative assessments may include observation, either directly or by videotape or interview with the client and others. Qualitative assessments often capture those experiences that cannot be directly quantified or for which quantification holds little meaning. They provide the client with the opportunity to identify issues, experiences, or goals that may not be previously identified on a quantitative measure.

Both qualitative and quantitative assessment formats are important in the AT assessment process and for evaluation of the outcomes of AT use. Quantitative measures allow comparison of experiences of a large number of individuals and a well-constructed instrument is essential in building evidence to support the efficacy of AT use. Qualitative methods provide a rich description of the experiences of AT use, which may not be readily apparent from the use of quantitative instruments alone. Together these methods can provide strong support for AT use, both on an individual and collective basis.

Norm-Referenced and Criterion-Referenced Measurements.

Two commonly used standards are available for measuring performance (for both the human and the total system): norm referenced and criterion referenced. In norm-referenced measurements the performance of the individual or system is ranked according to a sample of scores others have achieved on the task. Norm-referenced measures usually produce a percentile rank, a standardized score, or a grade equivalent that indicates where the individual stands relative to others in the representative sample (Witt and Cavell, 1986). When selecting a norm-referenced test for use, it is important to review how the norms were developed. Norms need to be relevant to the population for which the instrument is being used. They need to be recent and representative (Wiersma and Jurs, 1990). In other words, the characteristics of the sample used to develop the norms must be similar to those of the client group for which the assessment is being used. The items that form the instrument need to be relevant to the client group. For example, assessing visual-perceptual skills by using blocks is not relevant for most adults. Similarly, use of outdated questions or materials will not give an accurate picture of the client’s abilities. For example, testing keyboarding skills on a typewriter will give some information on keyboarding skills but does not cover the full range of skills required to use a computer (Miller Polgar, 2003). An alternative way to assess human or system performance is to rate the performance according to a specified criterion or level of mastery, which is referred to as criterion-referenced measurement, and the person’s own skill level in using the system is used as the standard. As an example of this approach, Jagacinski and Monk (1985) evaluated joystick and head pointer use by young adult nondisabled subjects. They found that skill in using these devices is acquired with some difficulty over many trials. The criterion used was whether the individual’s performance (time to move to target) did not change by more than 3% over a period of 4 consecutive days (Figure 4-1). In Figure 4-1, the horizontal axis represents the elapsed practice time and the vertical axis represents how quickly the person has been able to use the joystick or head pointer to move to a target. The horizontal dotted line is the final level of performance and serves as the criterion of performance. Using this criterion, they found that joystick use required 6 to 18 days and head pointer use required 7 to 29 days of practice to reach the criterion level of performance.

When the criterion-referenced approach to measurement is used, two desirable goals are accomplished. First, the assessment of progress is based on the person’s unique set of skills and there is no attempt to relate this performance to a normalized standard. In this example, the two alternative ways of accomplishing the same task (joystick and head pointer) are compared to determine which method is likely to result in a higher skill level. The second goal is accomplished by using the person’s own performance as a standard for measuring progress. Goal attainment scaling (King et al, 1999) is one standardized process of developing criteria that are specific to the client and task that are then applied to evaluate outcomes.

Methods for Gathering and Interpreting Information.

There are several methods used to gather and interpret quantitative and qualitative information about the consumer: (1) collection of the initial database, (2) interview procedures, (3) clinical assessment, and (4) formal assessment procedures (Dunn, 1991). Often, more than one method is used to gather information about the same aspect of a consumer’s skills, the context, the activity, or the use of assistive technology. For example, information on an individual’s hand function can be collected through each of these methods. The use of multiple sources of information is illustrated by Sam, a 22-year-old man with quadriplegia secondary to a complete C6 lesion of the spinal cord, who is being evaluated for his ability to access a computer.

Information collected for the initial database may include the reason for referral, medical diagnosis, and educational and vocational background information. This information is collected during the referral and intake phase of the service delivery process; its purpose is to provide preliminary data for planning the assessment. Sam’s medical diagnosis is complete quadriplegia at the C6 level. If we refer to a text describing the effects of spinal cord injury at the C6 level on arm function (see Table 3-8), we expect Sam to have scapular movements, shoulder flexion, elbow flexion, and wrist extension but to lack finger flexion and extension. Most medical histories do not provide information on the consumer’s assets and functional abilities. In some cases we may unintentionally limit the consumer’s potential if we fail to look beyond the expectations we have acquired on the basis of the medical diagnosis. As Christiansen (1991) points out, a medical diagnosis may provide guidelines for the assessment and expectations regarding the nature of the consumer’s impairments, but it is inadequate for planning intervention.

The interview, another way to collect information, can occur at different points in the service delivery process. Typically, an initial interview takes place during the needs identification phase as a means of gathering information regarding the consumer and his or her needs. It is important that the consumer, family members, rehabilitation or education professionals, and other care providers be interviewed. In Sam’s case, during the initial interview his goals and his particular needs related to using a computer are determined. The tasks with which he has difficulty performing are identified. Finding out whether Sam currently uses any adaptive equipment, or has in the past, to complete functional tasks also provides valuable information about his hand function. For example, Sam is able to sign his name by using an adapted splint to assist with grasping the pen, but it is difficult for him to write and he tires quickly. This difficulty has led him to pursue the use of a computer to facilitate taking notes at school and completing homework assignments. Another stage in which the interview is important is follow-up. At this stage, interviewing the consumer or caregivers provides valuable information on whether the device is being used and how. It is important that the ATP develop the ability to conduct interviews so that useful information is gathered.

Formal assessment procedures are administered in a prescribed way and have set methods of scoring and interpretation. Therefore, they can be duplicated and analyzed. Through formal assessment procedures, Sam’s arm and hand abilities can be quantified. For example, Sam’s muscle strength in his upper extremities can be evaluated by performing a manual muscle test (Daniels and Worthingham, 1986). Formal assessments should use standardized tests whenever possible. The ATP who uses such tests should evaluate the instrument development and psychometric properties to determine whether they are applicable to the client population and that the interpretation of the scores will be meaningful. Frameworks exist that guide a clinician’s critique of an evaluation (e.g., Miller Polgar and Barlow, 2002). These frameworks identify aspects of test construction, psychometrics, and clinical utility that are important considerations of an instrument’s usefulness in a given situation. Clinical assessment techniques involve skilled observation of the consumer and are used throughout the assessment and intervention process. The ATP may structure these techniques so that a series of steps is followed to determine specific skills or they may be intentionally left unstructured to see what takes place. Observation can be done during a simulated task in a clinic setting or in a context familiar to the consumer (e.g., classroom or workplace). Through skilled observation during the structured task of a series of typing tests, it may be observed that Sam’s typing speed and accuracy improve when he stabilizes himself with his left forearm and types with his right hand. Observation complements information obtained from standardized tests.

All these considerations lead to one very important conclusion: In the application of assistive technology systems, success is largely the result of the combined efforts of knowledgeable and competent clinicians who, in collaboration with informed consumers and caregivers, make decisions on the basis of both specific knowledge and experience. The complexity of the total system, including the diversity of the individual and of disabilities, technologies, and contexts of use, dictates that, when an assistive technology device is designed, best practice is often a matter of using clinical reasoning combined with results of established assessments.

Evaluation of Functional Vision.

The most critical visual skills needed for assistive technology use are sufficient acuity to see the symbols used in the system of choice or to identify small objects in the environment; adequate visual field to allow input of information from a display (e.g., the keyboard or the monitor) or the environment; and sufficient visual tracking ability (e.g., for reading or tracking a moving cursor). During the initial interview, known visual problems should have been identified, but a visual screening may also identify previously undetected deficits. The ATP can evaluate the effect of these deficits related to the use of technologies.

Identifying any visual field deficits a consumer may have is extremely important in the application of assistive technology. Visual field is commonly assessed by having the consumer look straight ahead and then indicate when he or she first sees a moving stimulus appear in the peripheral visual field. The stimulus is held approximately 18 inches away and moved in an arc toward the consumer’s midline. This testing is typically done for the right and left peripheral fields and the upper and lower fields. Peripheral field vision is considered intact if the stimulus is seen when it is parallel to the person’s cheek and impaired if the individual does not indicate that he or she sees the object as it approaches the center of his or her face (Dunn, 1991).

In some cases it is difficult to identify the effects of visual field limitations on assistive technology use. For example, individuals with a visual field deficit may make errors in typing because they do not see the whole keyboard. If the ATP is not careful, this performance may be interpreted as a physical limitation instead of a visual field deficit. If motor limitations were assumed, the keys may have been made larger so that the consumer could hit them more easily, an expensive and unnecessary step.

Visual tracking is the ability to follow a moving object. This skill is necessary for many assistive technology tasks, such as following a moving cursor on a screen, following the rotation of a plate with food in a feeder, or following objects in the environment while driving a wheelchair. Visual tracking is usually tested by having the consumer follow a moving object with the eyes. The object is held approximately 18 inches in front of the consumer and moved horizontally, vertically, and diagonally. The ATP notes whether the two eyes track together, whether the eye pursuits are smooth or jerky, whether there is a delay in the tracking, and whether the eyes can track without head movement.

Limitations in visual tracking ability may significantly reduce the options for specifying and designing an assistive technology system. In particular, these results have implications for the use of scanning augmentative communication systems in which the cursor moves left, right, up, and down (four-way directional scanning). It may be that an individual with a disability is able to track more easily to the right and down than to the left and up. In this case, two-way directional scanning, right and down, is preferable to using all four directions. When the cursor gets to the extreme right of the display, it automatically wraps around and begins from the left side again. Similarly, when it gets to the bottom, it wraps around to the top.

Visual scanning differs from visual tracking in that the object does not move; instead the eyes are moved to view different parts of a scene to find a desired object or location. This skill is used, for example, to locate obstacles during mobility and to scan a keyboard to find a specific key. The eye movements used in visual scanning are the same as those used in tracking. We often assess this capability by presenting arrays of pictures, symbols, words, or letters and asking the consumer to choose one item from the array. In Chapter 3 we described visual accommodation as the ability of the eyes to adjust to objects near and far. This component is impaired in many persons with disabilities, and it is important to be aware of possible accommodative insufficiency during the assessment process. A visual accommodation impairment may be observed by changing the visual focus between a monitor and keyboard. If the monitor and keyboard are far apart, the person may have more difficulty than if these objects are visually close. An individual’s ability to see objects (visual acuity) is affected by (1) the size of the object, (2) the contrast between the object and the background, and (3) the spacing between the object and surrounding background objects. These three considerations apply to symbols as well as to objects. For testing of visual acuity, actual objects, photographs, line drawings, orthographic symbols, letters, and words are used. It is helpful to have a set of materials that includes objects of 3 to 4 inches high; large letters, pictures, and symbols 1 to 2 inches high; and letters and words down to the size of standard typewritten letters (an eighth of an inch) (Cook, 1988). Information gathered from the initial interview can guide the ATP as to the type and size of symbol to start with. The goal is to find the smallest size of symbol that can be seen well by the consumer and that results in accurate selections, which are tested by presenting two items of the selected size and symbol type at a time to the consumer. The individual is asked to identify one of the two items using the manner in which he or she usually indicates a choice (e.g., eye gaze, pointing, yes/no). Three trials of each size and symbol are completed before proceeding to the next smaller size, until the individual is no longer able to identify the item successfully. It is desirable for the consumer to be able to see a small size for a number of reasons. First, the smaller the size, the larger a given array of symbols can be. Second, this allows greater options in hardware and software, including standard keyboards and software that have been developed for the nondisabled population.

If the consumer is able to read but appears to have difficulty seeing words, the effects of various foreground-background combinations (to improve contrast) and letter spacing can be assessed by using computer displays and software designed for this purpose (see Chapter 7). For example, most word processing software allows alteration in the background and foreground (letters) colors. Special software designed for persons with visual impairments also adds size variation to these capabilities. For computer applications, these features can improve performance.

We can improve visual performance by using enlarged graphics or text and by designing control panels with dark backgrounds and light lettering or controls. Identifying switches or keys with colors more distinguishable to the individual may be helpful. Switches can be light colored and placed on a dark background to improve recognition, and language board arrays can have bold dark letters or pictures on a white background, or vice versa. Likewise, video screens and the input array need to be carefully planned so that the amount of information presented is not cluttered.

Evaluation of Visual Perception.

As discussed in Chapter 3, visual perception is the process of giving meaning to visual information. Visual perceptual skills that need to be considered during assessment include depth perception, spatial relationships, form recognition or constancy, and figure-ground discrimination. Visual perception is an important consideration when considering the client’s ability to interpret information presented in a visual display or to safely navigate a mobility device in the environment. Formal testing of the consumer’s visual perception may have been completed before the assistive technology assessment, and results of this evaluation can be gathered during the initial interview. It is necessary to observe the consumer during functional tasks and note any apparent perceptual problems. If there is still some concern regarding the exact nature of the problems, a formal evaluation such as the Motor Free Visual Perception Test (Colarusso and Hammill, 1972) can be used.

Evaluation of Tactile Function.

There are three particular circumstances in which attention needs to be paid to the evaluation of tactile sensation. These occur during seating and positioning assessments, when evaluating tactile input for the use of control interfaces, and when considering the use of tactile alternatives to vision or hearing.

Somatosensory input is necessary for detecting forces or pressures exerted on the surface of the skin. Individuals who lack sensation may sit for prolonged periods without shifting position, which can result in skin breakdown. The ATP needs to be aware of an individual’s sensory status in these situations and be able to evaluate pressure on the sitting surface. Dunn (1991) presents a specific testing protocol for tactile response. Additionally, observation and monitoring of the skin surface is necessary. Tactile functions that are included in a somatosensory protocol include one-two point discrimination, perception of light touch versus deep pressure, perception of temperature, joint position sense, and localization of tactile stimulation. Somatosensory function is responsible for providing information regarding the location of a control interface, the movements required to activate it, and whether it is successfully activated. Lack of ability to receive appropriate sensory input (e.g., because of Hansen’s disease, nerve injuries, or sensory loss from aging) can severely limit the effective use of control interfaces. The initial interview generally reveals whether somatosensory deficits are present. During functional tasks, the ATP’s skilled observation can identify limitations caused by sensory deficits. Dunn’s (1991) sensory testing protocol can also be applied in this situation. In the case of decreased tactile sensation, the control interface needs to provide adequate feedback so that it compensates for the loss of sensory function (see Chapter 7). When visual or auditory function is inadequate for the input of information, we often use tactile substitutes (see Chapters 8 and 9). To determine whether this alternative sensory input is viable for an individual, tactile function must be evaluated. In particular, the skin response on one or more fingers is evaluated by using two-point discrimination and similar tests. This evaluation is necessary because certain diseases (e.g., diabetes) that result in loss of vision also cause reduced tactile sensation.

Evaluation of Auditory Function.

The ATP, through the initial interview and observation during functional tasks, should be aware of any significant auditory impairments that may affect device use. In cases of suspected hearing loss, a formal evaluation by an audiologist should be requested. Basic information sought by the ATP should include whether the individual responds to auditory stimuli, is distracted by some or all sounds, recognizes specific auditory stimuli (e.g., someone calling his or her name), and responds appropriately to auditory stimuli (Dunn, 1991). For example, many augmentative communication devices emit a beep when a selection is made. For some individuals, this cueing is helpful; however, for others the beep may produce a startle reflex that interferes with the succeeding motor movement. The individual may eventually habituate to the beep, but it is important to consider a device that has the option of disabling it.

Identifying Potential Anatomical Sites for Control.

In Chapter 3 we identify the control sites that can potentially be used by the consumer to operate a device (see Figure 3-10) and describe the various movements that each control site is capable of performing.

When individuals with physical disabilities are evaluated, it helps to keep in mind the movement capabilities of each of these anatomical sites and the hierarchy in which these sites are considered. The hands and the fingers are the preferred control sites because they are naturally used during manipulation tasks and finer resolution can be achieved. If the hands are not an option for control, the head and mouth are considered next. With the use of mouthsticks, head pointers, or light beams, it is possible to achieve the fine resolution and range needed to control a device. The next option to consider is the foot. Some individuals are able to develop fine control of the foot for typing (Figure 4-4); however, problems with positioning the device so that the user can see it make this site less desirable than the hands or the head. The least desirable sites are the legs or the arms because they are controlled by larger muscle groups, so the movements of these sites are gross in nature compared with the fine movements of smaller muscles (Cook, 1988).

Simulation of functional tasks is used to evaluate the types and quality of movement an individual possesses. Functional tasks are chosen for evaluation because they are often more meaningful to the consumer than physical performance components such as strength and joint range of motion. They also provide the ATP with an opportunity to gather qualitative information regarding the consumer’s movements, and results of such tasks are more likely to reflect the consumer’s true abilities.

We present a model based on clinical experience to determine the best anatomical site for accessing a control interface. The hands, being the control site of choice, are the first to be assessed. Basic hand function can be observed and rated by using a “grasp module” (Figure 4-5), which includes a total of seven functional grasp patterns. The consumer’s ability to complete each grasp pattern is rated (unable, poor, fair, or good). Notations are also made regarding how the consumer completed the movement and the factors that made it successful or not. For example, did the object need to be positioned in a particular way for the consumer to grasp it? Was there a delay in initiating the movement? Did the consumer have difficulty releasing the object? Was the movement pattern isolated or synergistic in nature? Did the consumer appear to have problems with depth perception when reaching for the object?

If the consumer has the potential for hand use, it is then necessary to determine the minimal and maximal arm range within a workspace and the resolution in hitting a target. A range and resolution board, as shown in Figure 4-6, can be used to measure both of these. If possible, the consumer is asked to use the thumb or a finger to point to each corner of each numbered square. If the consumer is unable to point to the corners, he or she is asked to touch each square with the whole hand. This provides information regarding the approximate size of the workspace and the best locations for a control interface and a rough measure of accuracy of movement. Both arms are evaluated as appropriate.

If the hands are eliminated as a control site, other anatomical sites must be considered. For example, we can also measure range and resolution for the foot and head. With a range and resolution board of smaller dimensions, the same task can be used to evaluate foot range and targeting skills and the consumer’s range and resolution with a mouthstick, light pointer, or head pointer. Appendix 4-1B shows a sample assessment form for documenting the information gathered during the physical skills evaluation. After completion of this component of the skills evaluation, the ATP should have a good idea of the user’s physical skills and the anatomical sites that can best be used to control an interface.

Selecting Candidate Control Interfaces.

Once the ATP has identified anatomical sites that the consumer can potentially use, the next step in the process is to select control interfaces that have potential to be used successfully by the consumer. In Chapter 7 we present a set of control interface characteristics that are useful in selecting interfaces that most closely match the consumer’s available anatomical sites.

Comparative Testing of Candidate Control Interfaces.

Once potential anatomical sites and candidate control interfaces have been chosen, next the consumer’s ability to use these interfaces is measured. Comparative testing provides the ATP with data on the consumer’s speed and accuracy in using particular control interfaces. These data can be used to compare different interfaces operated with a given site. If a control enhancer (e.g., mouthstick, head pointer) or modification (e.g., keyguard) is being considered, its use should also be evaluated (Chapter 7). This is one area where gathering quantitative information on the person’s ability to use the control interface is extremely valuable and can assist the ATP in making decisions regarding the selection of a control site and interface. It is also important to note the consumer’s preferences during this process.

During the assessment process, speed of response is often used to compare control interfaces. Speed of response is a temporal (time-based) measurement that can be quantified. Because these measurements are typically made in the controlled setting of the clinic, they must be carefully applied to contexts outside the clinic. Another measure used to compare control interfaces is accuracy of response. This is often based on moving to the correct position, and it is therefore a spatial measurement, rather than a temporal (time-based) measure. Measurement of accuracy requires a standard of performance. This is usually the number of correct responses out of the total number of trials. Speed of response and accuracy are generally inversely proportional to each other for novice users.

When these two basic parameters are defined, methods for measuring them can be described. The selected control interface is first placed in a position where the consumer can activate it. It may be necessary to try different locations for the control interface before finding the position at which the consumer has the greatest control. The consumer’s time to move from a rest position to target the control interface can be measured with a stopwatch.

Computer-assisted assessment provides several useful features. First, data collection and analysis can be automated, relieving the clinician of tedious record keeping. Performance measures for each possible control site/interface pair can be obtained. The effects of different positions for the control interface or the use of control enhancers and modifications can also be measured. Because several different control site/interface combinations can be evaluated, this data collection process can facilitate the choice of interfaces on the basis of measured results. Second, the computer can provide a variety of contingent results (including graphics, sound, and speech) when the control interface is activated. This variety of results not only makes the task more interesting, but it also can allow assessment of visual and auditory capabilities.

Human/Technology Interface.

The human/technology interface is the portion of the device with which the consumer directly interacts. The most general human/technology characteristics, which apply to all devices, are the physical properties. These include the force exerted by the human/technology interface on the person and the force exerted by the person on the interface, the size and weight of the interface, and its texture and hardness. A seating system may be too hard or soft to be effective, and this feature can be related to the needs of the individual consumer. All human/technology interfaces must be attached either to the person, to a wheelchair, or to a stable work surface. Consideration of this “mountablilty” characteristic can often mean the difference between success and failure of the human/technology interface. For example, if a consumer has very limited range of arm movement, a switch must be positioned within this range.

Just as the human user exerts forces on the human/technology interface, the human/technology interface provides feedback to the user. This may be as a direct consequence of the interface. For example, a seat cushion exerts a certain force, depending on its materials, design, and construction. In other cases the user feedback is a separate component, such as a flashing light indicator on a television control or a tactile display on a reading device for a person with total visual impairment. Human/technology user feedback sources can be described in terms of the characteristics of magnitude, type, and origin. These characteristics can be matched to the consumer’s needs. For example, the magnitude of a visual display is the brightness of the light. The types of human/technology interface feedback are other characteristics and include visual, auditory, and tactile varieties. Each of these can be matched to the corresponding user skill. The origin refers to the source of the feedback, such as that provided by a seat cushion or the voice output provided from the screen reader.

The next three characteristics listed in Box 4-2 apply to human/technology interfaces used with electronic assistive devices (including power mobility). The number of inputs required to operate any device is a characteristic. This characteristic is referred to as the size of the input domain (see Chapter 7). There are many types of control interfaces available, with varying numbers of inputs and requiring different physical skills for activation. The most appropriate control interface for any given consumer is largely determined by the physical and interface assessments that are described here and in Chapter 7.

Depending on the size of the input domain related to the consumer’s needs and skills, a selection method can be chosen. In Chapter 7 two basic selection methods are described: direct and indirect. In direct selection, all the choices are presented to the user at one time and the user has the physical ability to choose any one element directly. With indirect selection, there are intermediate steps required for the user to make a selection. If the number of input signals required (on the basis of needs) is greater than the number the consumer can control (on the basis of physical skills), then some form of indirect selection must be used. Individual devices may have both these methods or they may be restricted to only one method. Direct selection requires greater physical skill than indirect selection; however, indirect selection requires greater cognitive, visual, perceptual, and possibly auditory abilities. The consumer’s skills must be taken into account when specific device features are chosen.

Selections are made from a selection set consisting of the choices available to the consumer. Features of this set include size, number of choices, format (e.g., print, tactile), and type of symbol (real objects, pictures, computer icons, line drawings, traditional orthography, or symbols used to represent an idea). The type of symbol system that is most appropriate to a given individual is determined during the language assessment. The question of symbol system type is obviously essential for augmentative communication devices, but it is also important in other applications. For example, in electronic aids to daily living (EADL), the devices to be controlled must be labeled, and often symbols are used rather than words to make the systems available to persons who have difficulty in reading. Speech labels, generated by synthetic speech, are also used in the selection set for individuals who have either visual or cognitive limitations. Along with determining the type of symbols used in the selection set, the size of the selection set is also determined. The number of choices required is often dictated by the consumer’s needs and by other factors such as how many will fit on a display given the consumer’s visual acuity. The choice of these features for a consumer is based on his or her skills in several areas, including sensory, cognitive, and language.

The Processor.

Recall that the processor is the element of the assistive technology device that relates the human/technology interface to the other components. Sometimes this is simply a mechanical linkage (e.g., in a reacher), and in such cases there are not many choices in characteristics. However, processors for electronic devices have several characteristics that must be carefully matched to the consumer’s needs and skills. The first of these is the basic set of commands that are necessary to operate the device. It is important to ensure that the consumer can use these so that the system will be functional for the consumer. For example, in a powered wheelchair system the basic commands are forward, backward, left, and right. In a communication device, some basic commands include printing a document and speaking. In an EADL the commands may include lights on and off, TV channel selection, and telephone dialing. These are essential for operation. The greater the number of commands, the more flexible the system is to the user. For example, an EADL that can control the television with three functions (power, volume, and channel), turn three appliances on and off (lights, drapes, and door lock), dial a telephone (three commands), and access an emergency message machine has 10 functions. The more commands included, the more confusing the system can become. The consumer, family, care providers, and ATP need to evaluate the effect of a specific command size during the assessment.

A second characteristic of the processor is the control parameters. In contrast to commands, control parameters allow adjustments to be made to the system; they are nice to have but not always essential. Control parameters include such things as variable speed for forward and reverse or indoor and outdoor speed levels in a powered wheelchair. In an augmentative communication device, control parameters adjust the voice synthesizer pitch, voice type, and rate to affect the way the speech output sounds. A control parameter also provides the ability to switch between different applications for multiple activity outputs. For example, it is possible to operate an EADL, communication device, and computer access system from a powered wheelchair controller. Individual control parameters need to be presented to the consumer for the systems being considered, and both the consumer and the ATP need to evaluate their effectiveness.

The final general processor characteristic is data or information processing. In this case the device is internally processing information rather than dealing with commands or control signals. One example, used in augmentative communication systems and screen readers for the blind, is the generation of spoken output from text using software programs. By listening to several speech systems, the consumer can determine the intelligibility of each and identify which one is preferred.

Another type of information processing is word prediction, in which the software program guesses at the desired word on the basis of the entries the consumer makes. This type of application can also adapt to the user by learning his or her most frequently used words. Encoding involves the use of a symbol (e.g., number, letter, mnemonic, color) to represent a vocabulary item or a command (e.g., TV ON in an EADL). The user selects the code instead of directly selecting the element, which can increase the user’s rate of data entry. Encoding schemes can be cognitively difficult, and the consumer should try them during the assessment. The consumer may indicate a preference of one encoding method over another after having a chance to try several.

Information processing is also used in sensory systems to convert the input from the environmental sensor to a form that can be presented to the user. For example, a hearing aid uses a microphone to detect voices, amplifies them (data processing), and presents the amplified signal to the ear (see Chapter 9). Different hearing aids have different data processing, and the consumer can evaluate this characteristic.

Environmental Interface.

As discussed in Chapters 2, 8, and 9, the environmental interface is that portion of the assistive technology system that is used to take in information from the external world for use in a sensory substitution system. For example, when the person has a visual limitation, we use a camera, and when a person has an auditory impairment, we use a microphone. Characteristics that apply to this element include the range of the input signal (i.e., how big or small the signal can be and still be detected). The smallest signal that can be discerned from background noise is the threshold. As an example of how these characteristics can be applied, consider the two problems of reading and mobility for persons with severe visual impairments. For reading, the device needs very little range because only one letter or line of text needs to be viewed at a time. However, for mobility the environmental sensor needs to take in a variety of sizes (e.g., from a dish to a tree). For reading, the threshold is low (a letter in fine print), but for mobility the threshold can be much higher.

Activity Output.

The activity output is what the system accomplishes for the consumer (e.g., communication, mobility, manipulation). The first characteristic that describes the activity output is its magnitude. This includes the volume for a speech synthesis system, the force or torque generated by a powered wheelchair, and the brightness of a video screen display. Precision is a measure of how accurately the system performs the functions and how exactly it accomplishes its task. For example, a reacher may be able to pick up a cup but not a button. If the consumer needs to pick up the button, then this particular reacher has insufficient precision to accomplish the task. If an output can be used in different contexts or can be used to accomplish different goals for the consumer, we would say that it is flexible. Flexibility can be an important factor when the consumer has many tasks to perform. Careful consideration of context must also be included in choosing specific activity output features.

Physical Construction.

The final category of characteristics is physical construction. No matter how well a system works in an assessment session, it will not be effective in everyday use unless the person has access to it at all times. This is determined primarily by the mountability of the system. Special consideration must be given to both the mounting of the system (or placement on a desk) and the attachment of any components to a wheelchair. For example, mounting of a communication system to a wheelchair must be considered during the assessment to ensure that the chosen system is compatible with the consumer’s wheelchair.

Portability is a measure of the degree to which the device can be moved from place to place. This characteristic includes a consideration of size, weight, and power source. For electronic devices, portability often requires that the device be battery operated and that it be small and lightweight enough to be carried or attached to a wheelchair. If the person is ambulatory, his or her ability to carry the device needs to be assessed. There are differences in batteries (e.g., life may be a few hours or a few days between charges) and size and weight. For mobility devices, the ability to transport the wheelchair in the trunk of a car may need to be considered. Some wheelchairs fold so that they can be transported in a car trunk, whereas others, such as powered wheelchairs, do not typically fold.

Generally consideration of the characteristics of color, shape, and overall design are done last when a recommendation for assistive technologies is developed for a consumer. We refer to these as packaging characteristics. Consideration of the consumer’s preferences in this area can contribute to motivation to use the system and to overall user satisfaction. However, the consumer’s packaging preferences cannot always be integrated into the system (e.g., the wheelchair may not come in bright orange). All these features should be discussed with the consumer and others to ensure that the device selected will meet the consumer’s needs.

Evaluating the Match Between Characteristics and the Consumer’s Skills and Needs.

It is our premise that a large part of the assessment up to this point is best completed without the introduction of specific devices. The focus of the assessment remains on the functional results to be achieved by the technology instead of on the secondary features of technology, such as color, size, and design. Once the basic functional characteristics have been determined, differences in the secondary factors of size, weight, color, and overall design become important, and they may be the basis for a final decision. After the assessment phases described earlier, one or more devices that have the potential to meet the consumer’s skills and needs are identified for the consumer to evaluate. There are two primary ways in which the ATP can evaluate specific technologies for use by the consumer: (1) trial using the actual device and (2) simulation of device characteristics.

Ideally the consumer will have the opportunity to try the devices being considered and evaluate their usefulness before a recommendation is made. However, because of the expense, it is not always possible for the ATP to have access to every available device, nor is it a prerequisite for conducting a skilled assessment. It is desirable that the ATP have available a set of devices that represents a broad range of characteristics. A service delivery program can carefully choose equipment to be used for evaluations, making it possible to address the major characteristics of devices during consumer assessment. Sometimes a short trial during a one-time assessment is not adequate and it is necessary to have the consumer use the device for an extended period. In some cases a local manufacturer’s representative might loan a device to the ATP for a consumer trial. Other manufacturers and service delivery programs lease devices for this purpose. If these devices are available, it is helpful to demonstrate the various features to the consumer and have the consumer try them. There may be two or three devices being considered, and, if possible, each device should be tried and evaluated by the consumer. In lieu of having the actual device available, the ATP can simulate device characteristics. Simulation requires that the ATP be knowledgeable about the characteristics and features available for specific assistive technologies. For computer-based products, the assistive technology adaptations are often software based, and demonstration disks can be obtained from manufacturers or downloaded from a manufacturer’s Web site. These demonstration programs illustrate the essential features of the software, but they are not fully functional and their use is time limited.

To position a control interface for simulation during assessment, universal mounting systems that can be adjusted and placed in various positions can be used. This step is important to ensure that the control interface is in a functional position for the consumer and that it remains stable during the assessment.

Effects of Errors in Assistive Technology Systems.

An important operational characteristic of assistive technology systems is the way in which they deal with errors. Two types of errors are of concern. Random errors are infrequent and are generally chance occurrences. An example of a random error is the consumer’s inability to understand a voice synthesizer because of high amounts of ambient noise. If the noise is not present, there is no error, and even if there is noise it may not lead to an error in interpretation. It is only the random co-occurrence of the need to use the voice synthesizer, the presence of noise, and a listener who does not understand the output that creates the error. Random errors may recur, but they are not consistently present in the system. We can do very little to avoid this type of error in the assistive technology system design process.

Of greater concern are periodic, or regular, errors, which occur under predictable conditions. These errors may also be infrequent, but they are foreseeable. As an example, many letter-to-speech software programs make mistakes in pronunciation when used with voice synthesizers. The mispronunciation always occurs whenever the particular word is entered. This type of error can be dealt with in the design process. For our example of mispronunciation, exception tables are typically used so that the utterance sounds correct although the letter-to-speech rule makes an error. There are several effects of errors on assistive technology system performance, including loss of information, injury, and embarrassment. All three of these can occur in the same system, and they may be due to the human, the activity, the context, the assistive technology, or the interaction of all of these components. For example, a power wheelchair will not function if the user does not regularly charge the batteries. The user must somehow cause the action that results in the batteries maintaining a charge, and the power wheelchair system must provide accurate information about the degree to which the batteries are charged. Error-free function here relies on the successful integration of the human with the technology. Loss of information is a common effect associated with augmentative communication systems (see Chapter 11) and sensory aids (see Chapters 8 and 9). Loss of information refers to an interruption in the output of the system, whether it is auditory or visual, as in a voice output communication aid, or physical, as in the power to propel an electrically powered wheelchair. It can occur because the human operator makes an error in motor, sensory, or cognitive performance or as a result of a device error. Although the net effect on system performance of either of these errors (human or device) may be the same, it is important to distinguish between them to correct the problem.

When the human operator makes the errors, the distinction needs to be made as to whether the cause is lack of capacity (e.g., inability to control excessive tremor resulting in erroneous selections or visual limitations in reading a display) or lack of skill (inadequate experience or practice in using the device). If the problem is the capacity of the user, then modifications must be made in the system (e.g., using a keyguard to prevent erroneous entries or an enlarged display screen to improve visibility). If the problem is one of skill, training may help reduce the number of errors.

Physical injury is a more serious effect of a system error. This type of error can occur in a mobility system (see Chapter 12) if, for example, a braking system fails or a motor fails to turn off. Consideration of this type of error leads us to the concept of “fail-safe” design. This approach attempts to anticipate the types of errors (termed failures when caused by the device) and to ensure that, if they do occur, the probability of injury is minimized. For example, if a power wheelchair controller fails, it should fail in the off state. If it fails in the on state, the user may be injured because the chair cannot be controlled. Similar to loss of information, the capacity or the skill of the user can cause physical injury. A final general effect of assistive technology system errors is embarrassment. This effect is somewhat unique to assistive technologies, and it is a direct result of the role that assistive technology systems play in the daily life of the user who has a disability. Because the tasks being performed cannot be accomplished without the system, its use is continuous throughout the day. Over a long period, system errors leading to embarrassment are inevitable. The embarrassment may be relatively minor, such as a manipulation system dropping a spoonful of food. In other contexts, it may be much more significant. For example, an augmentative communication device may fail and produce the wrong utterance. If the context is a presentation in an important meeting and the mistaken utterance is an obscenity, the consequences are potentially very negative. To place the importance of this type of error in perspective, recall that the device is often perceived by both the user and other people as being a part of the user. Thus, the user is held responsible for an inappropriate utterance just as if he or she had used his or her own voice to produce it.

The errors and their resulting effects may arise from any of the components of the assistive technology system or their interaction. The human error may be related to capacity or skill. The device may malfunction, in which case the error is related to the design. The context may cause an error. For example, the pressure relief properties of a wheelchair cushion may be impaired if the cushion is exposed to extremely cold environments for a prolonged time and the cushion materials freeze. An example of an error that is caused by the interaction of the components of the HAAT model relates to devices that have many functions, with complex commands required for successful activation. In part, the error is caused by the capacity of the user to learn how to operate the device. It is also caused by the design of the device that requires complex actions for successful operation. Some of the concepts related to human factors that were discussed in Chapter 2 are relevant here.

It is clear from this discussion that identification and reduction of errors can occur at several points in the assistive technology process. Initially, incorporating a design and accompanying soft technologies that are congruent with universal design principles can minimize errors. Errors can be identified and possibly corrected through use of a thorough evaluation that leads to a suitable device recommendation, coupled with a trial period. Finally, errors in the assistive technology system are identified and reduced through follow-up with individual users and after market research into the effectiveness of the system.

Decision Making.

To propose a set of candidate assistive technology devices for a consumer, it is necessary to choose characteristics of these systems that will meet the needs and be consistent with the skills possessed by the consumer. The most important principle in this process is the relationship between the tasks the assistive technology device must accomplish for a person (embodied in the consumer’s goals) and the characteristics that must be contained in the device for those tasks to be accomplished. Each goal may be accomplished only if a set of essential characteristics is included in the assistive technology system. For example, the goal may be mobility, and the characteristics of the type of cushion, wheelchair type, and color all contribute to the accomplishment of this goal.

Many characteristic-goal relationships are subtler, however, and generic characteristics of devices are not always equivalent to specific features of commercially available assistive technologies. For example, a generic characteristic of all EADLs is turning lights on and off. However, different manufacturers of EADLs may accomplish this function in different ways. Developing recommendations and a plan for implementation should be based on the consideration of device characteristics that have been evaluated by the consumer.

Computer-based expert systems that assist in the decision-making process for assistive technologies are being developed. Depending on the expert system, collection and interpretation of data are incorporated. Expert systems use artificial intelligence to guide the ATP through the assessment and decision-making process. Expert systems attempt to mimic the skills of an ATP by using software programs that are capable of making decisions much like humans do. In assistive technologies, several preliminary systems have been developed. Garrett et al (1990) have developed an expert system called VOCAselect for use in selecting augmentative communication systems for specific consumers. Their system is based on 17 features that are determined during the assessment process. In addition to features related to consumer performance (e.g., input method, vocabulary size), they include physical construction (e.g., portability) and information regarding available support services (e.g., acceptable price range, training availability). These factors are then related to specific features of each available communication device. The expert system matches the specific requirements of the user, on the basis of goals and needs and on assessment of skills, to appropriate devices. By including the weight of factors (e.g., characteristic A is twice as important as characteristic B) and a scale of responses (e.g., priority for speech output is nine out of 10), this type of expert system can focus on specific options even more closely. Garrett et al report that preliminary trials indicate exact agreement in device selection between the expert system and a speech-language pathologist.

Stapelton and Garrett (1995) carried out an evaluation of this system. Respondents to a survey indicated strongly (greater than 79%) that this system would be of value in making recommendations for augmentative communication systems. They also present an example of the use of this program for a specific case. Stapelton et al (1995) extended the VOCAselect concept to the selection of computer adaptations (see Chapter 7). This computer program is similar to VOCAselect, but it is built on characteristics of devices and software used to make computers accessible to individuals who cannot use a keyboard or mouse for entry or the standard screen for output. In operation this software is functionally identical to VOCAselect. Stapelton et al (1995) present an example of the use of this system.

Regardless of whether an expert system is used, the process we have described is highly effective in defining the features of a recommended system. It is important to recognize that the features that are most limiting must be considered first, followed by those that are less restrictive. For example, in an augmentative communication system, the type of symbol system is often the most limiting characteristic. If a consumer requires pictures as a symbol, many devices are eliminated immediately. In contrast, spoken output as a characteristic is not as limiting because most devices use similar speech synthesizers. For each type of assistive technology, it is important for the ATP to identify a set of general characteristics that fit within the categories of Box 4-2. These are presented in later chapters. If the characteristics are generic, then specific features can be selected in sequence to define the final assistive technology system. The major advantage of the assessment methods described here is that they are based first on a consideration of the consumer’s goals and skills and second on a consideration of assistive technology system characteristics. Thus the system is matched to the consumer (within the limits of current technology) rather than the consumer being forced to adapt to the system. Without a structured approach such as the one presented here, however, it is very difficult to meet consumer’s goals.

It is clear that many characteristics of devices should be considered, and the features (and their costs) will differ from one system to the next. In addition to specific features of the device, other important factors include the contexts of use, the amount of training required before the device can be used effectively, cost, availability of a family member or caregiver to support and facilitate the training and implementation of the device, and ease of use of the device.

Training.

Bailey (1989) defines training as “the acquisition of skills, knowledge, and attitudes that will lead to an acceptable level of human performance on a specific activity in a given context” (p. 387), which is referred to as performance-based training. In the field of assistive technology, prior authorization from the funding source to conduct training is usually required. For a funding source to authorize training, an estimate of the amount of time that will be needed is typically required, with the result that training becomes time based rather than performance based. Time-based training is completed within a specified period, regardless of whether the user achieves a level of skill. Without adequate training, there is an increased likelihood that the device will be abandoned. The training process is facilitated if the ATP starts out by developing a set of well-defined, measurable objectives for training. These objectives help focus the training sessions and serve as an indicator for termination of training. It is also important that there be one person affiliated with the consumer who takes on the role of the facilitator and learns the operation of the device and basic concepts so that he or she can assist with the use of the device as needed.

Training oriented toward establishing operational competence is initiated at the delivery and fitting (Pallin, 1991). This phase of training is intended to make it possible for the user of the technology, his or her care providers and family, and any other support person to begin using the assistive technology system. Examples of considerations included in training for operational competency for the consumer are (1) how to turn an electronic device on and off, (2) making adjustments in operational parameters (e.g., adjusting a scanning rate), (3) loading an initial vocabulary in an augmentative communication system, (4) explaining basic maintenance (e.g., battery charging, cleaning), (5) introducing basic functions and how they work (e.g., choosing what to say on a communication device, using an adapted telephone dialer), and (6) basic troubleshooting so that the consumer and others have some strategies to use if problems develop with the system. It is important to present information in small doses to avoid overwhelming the consumer and others, particularly for a complex system. At the initial fitting session it is only necessary to present enough information so that the consumer can begin to use the system. Subsequent training addresses the acquisition of the necessary skills for more advanced operations.

In addition to basic operational competence, it is necessary for the consumer to develop strategies that maximize the effectiveness of the system. To facilitate this, the ATP provides training for strategic competence. The training focuses on the application of the system rather than on basic operation. As this phase of training progresses, the consumer begins to develop his or her own set of strategies. For example, the person using a manual wheelchair will develop strategies for navigating curbs or inclines and the user of an augmentative and alternative communication (AAC) device will develop strategies for communicating in a noisy restaurant.

Performance Aids.

A document or device containing information that an individual uses to assist in the completion of an activity is called a performance aid. By decreasing the amount of information to be remembered, the performance aid reduces the amount of cognitive processing required to complete an activity. With a performance aid, the user does not have to rely as much on long-term memory, which results in reduced errors, increased speed for certain tasks, and a reduced amount of training required. Performance aids do not necessarily have to be written; picture symbols can also be effective for individuals who cannot read. Bailey (1989) describes five quality standards for performance aids: (1) accessibility, (2) accuracy, (3) clarity, (4) completeness and conciseness, and (5) legibility.

Performance aids are commonly used with individuals who have memory deficits as a result of damage to the brain. One type of performance aid is simple step-by-step instructions that assist the user in carrying out a sequence of tasks. For example, Tim is a young man who has sustained a head injury. He uses a computer to complete school assignments but has problems remembering the sequence of steps to get into his computer word processing program. The steps to do this have been simply written and are posted next to his computer. Because Tim also has visual acuity problems, the instructions are printed in large, bold letters. For Tim, this simple performance aid has meant the difference between success and failure in using his computer.

Another type of performance aid assists in remembering several items of information. An example of this type of aid is a printed list of codes with their meanings, which an individual may have stored in his or her augmentative communication system. Often such a list such is attached to the side of the device so the user can view it easily as needed. Sometimes codes and their meanings are built into software programs and presented on the screen each time the user selects a letter.

Written Instructions.

Written instructions should be considered an integral part of the system and be available to the user at the time of the system delivery. Instructions are helpful when step-by-step directions with detailed information are required or when graphic information needs to be presented. Written instructions may be compiled and presented in the form of user manuals, handbooks, or computer software. The ATP must not assume that the instructions provided by the manufacturer are going to be adequate. Written instructions provided by the manufacturer of the system may include too little or too much information or they may be difficult to follow by the user. It is recommended that instructions from the manufacturer be reviewed and supplemented as needed. When the manufacturer’s documentation is overwhelming, the ATP can review the documentation and condense it into a quick reference sheet that provides simplified and frequently used information.

Bailey (1989) provides detailed guidelines for developing the various types of written documents, including software documentation. It is important to remember to keep the audience in mind and to write the instructions for the people who will use them. For example, if the primary person facilitating the performance is the parent, the instructions may be different from those generated if the facilitator is a teacher. In the field of assistive technology, this may mean a new or revised set of instructions for each individual consumer, even for use of the same device.

Functional Independence Measure.

The FIM (Instrument is an example of one functional outcome measure. We have chosen the FIM(as an example because it is widely used in assessing the outcomes of rehabilitation interventions. The FIM(is based on a medical model of assessment that places importance on cure (Smith, 1996). The FIM measures the individual’s performance on 18 items under the categories of self-care, bowel and bladder management, transfers, locomotion, communication, and cognition (Uniform Data System for Medical Rehabilitation, 1997). The scoring of the FIM(is on a seven-point scale. The individual only obtains the full seven points if he or she does not require any assistance or assistive device to perform a function. Thus the FIM(is not directly applicable to assistive device outcome measurement because its maximal score in any category can only be obtained if the person does not use any technology. Use of technology automatically implies that the person is not totally functionally independent. This appraisal of functional independence is inconsistent with the current view that an individual is independent if he or she can manage his or her own life (Smith, 1996). Another concern regarding the FIM(and other tools that measure function is that they do not impart information regarding the impact of assistive devices on the quality of life of the user (Jutai et al, 1996).

Canadian Occupational Performance Measure.

The Canadian Occupational Performance Measure (COPM) (Law et al, 1998) assesses the client’s perception of the importance of self-identified occupational performance goals and his or her satisfaction with that performance. The measure uses an interview format to identify goals in the areas of self-care, productivity, and leisure. The client rates the importance of each of these goals and their satisfaction. The instrument can be used before and after intervention. It is quite flexible because it allows the user to adapt the instrument for a specific purpose. The user can ask the client to think specifically of self-care, productivity, and leisure activities that he or she wants or needs to do when using a particular type of assistive technology. Miller Polgar and Barlow (2002) used this instrument as an outcome of seating and mobility intervention. Its utility was somewhat limited unless the client was asked to think about goals that specifically involved the use of assistive technology. This instrument has been used with many different client populations. Once the client becomes comfortable with identifying his or her own goals, the COPM is a very useful outcome measure.

Quebec User Evaluation of Satisfaction With Assistive Technology.

Five criteria were used in the development of the Quebec User Evaluation of Satisfaction with Assistive Technology (QUEST) (Demers, Weiss-Lambrou, and Ska, 1996). The first is the recognition that user satisfaction is a multidimensional phenomenon that includes a broad range of variables, each of which can affect the user’s satisfaction with assistive technology. The second criterion relates to the inclusion of three types of variables: those involving the environment (context in the HAAT model), pertinent features of the person’s personality (the human), and the characteristics of the assistive technology itself. The third criterion is the recognition that the user should determine the relative importance of the satisfaction variable. This reflects the highly subjective nature of the user satisfaction measure. The fourth criterion provides for the user to express his or her opinion freely within the constraints of an interview context. Finally, the QUEST was designed to be simple to understand and easy to use by ATPs when evaluating satisfaction. The QUEST requires approximately 30 minutes to administer and is guided by a three-part form.

The first part of the instrument is the general information questionnaire. This form is designed to determine the context in which the user’s satisfaction or dissatisfaction developed. It consists of 18 open-ended questions designed to include the three domains of environment (context [e.g., living arrangements, social supports, funding considerations]), user characteristics (human [e.g., sex, age, nature of disability, types of functional problems]), and assistive technology characteristics (e.g., when the device was acquired, frequency and patterns of use or nonuse, number and types of assistive technologies used).

The second part of the QUEST instrument is an assessment of satisfaction. This includes a set of 27 variables that represents the factors most likely to affect user satisfaction with assistive technologies. Each of the variables represents a specific category, but they are randomly ordered in the presentation to the user. This ensures that the user’s answers are not artificially influenced by the category of the question. Three tasks are used in this part of the evaluation. In the first task, the person is asked the degree of importance that he or she attributes to each variable. Each of the variables is printed on a card. There is a board for classifying the variable from very important (a score of 3) to no importance (0). The evaluator asks the user where he or she would like each card placed and then circles the response on the form. After completing the 27 variables, the user is given an opportunity to add other satisfaction variables that he or she feels are important. This task personalizes the assessment in terms of the individual’s preferences. The second task requires that the evaluator reorganize the variables according to the three categories, and only the variables selected as being quite or very important (scores of 2 or 3) are included. For this task, a six-point scale (0 [very dissatisfied] to 5 [very satisfied]) portrayed on a semicircular dial is used. For each of the variables included from Task 1, the user is asked to indicate his or her satisfaction by moving the dial or instructing the evaluator where to place it. The evaluator then circles the result on the summary form. Finally, the user is asked to express a global satisfaction score for the device. This task, as in Task 1, personalizes the assessment to the individual user. The third and final part of the QUEST requires that the evaluator reorganize the results from Part 2 into the three global categories (environment, person, and assistive technology). Only the values for those variables rated as quite or very important in Task 1 are included. The summary sheet then serves to facilitate the interpretation and use of the data in assessing satisfaction and addressing those areas in which satisfaction is low.

Weiss-Lambrou et al (1999) used the QUEST to determine satisfaction of consumers with seating aids. They describe the application of QUEST to this situation with a group of 24 subjects who used modular seating aids (see Chapter 6). They found that the most important variable (user comfort) was also rated as the least satisfying. This study illustrates the value and importance of a consumer-driven measure of user satisfaction. Weiss-Lambrou et al describe the application of QUEST in this context in detail.

Assistive Technology Abandonment.

One of the most tangible indicators of lack of consumer satisfaction is when the consumer stops using a device although the need for which the device was obtained still exists. This situation is called technology abandonment, and it is useful to look at some of the factors that lead to it. Phillips and Zhao (1993) surveyed more than 200 users of assistive technologies and identified four factors that were significantly related to the abandonment of assistive technologies: (1) failure of providers to take consumers’ opinions into account, (2) easy device procurement, (3) poor device performance, and (4) changes in consumers’ needs or priorities.

More recent research examined personal and social factors that predict assistive technology abandonment. Pape, Kim, and Weiner (2002) conducted a review of the literature related to assistive technology abandonment to look at how the personal meaning attributed to assistive devices influences their integration into the user’s daily life. They found that psychosocial and cultural variables were primary factors in determining the meaning individuals assigned to assistive technology. In particular, their expectations of how the device would function, the social costs of using the device (i.e., cost/benefit of device use), and an outlook that disability did not define the user as a person were the primary factors that contributed to whether a person integrated assistive technology into his or her life (Pape, Kim, and Weiner, 2002). Reimer-Weiss and Wacker (2000) examined factors that predicated assistive technology use in individuals with disability. They found that the relative advantage of the assistive technology in the user’s life and the user’s involvement in the device selection process were predictors of device use or discontinuance.

Scherer et al (2005) have developed a group of measures that help determine the match between the individual and technology. The Matching Person and Technology assessment is described shortly. A recent study examined the validity of the assumptions that guided the development of this instrument. The results of the study supported these assumptions, specifically that personal characteristics related to mood, self-esteem, self-determination and motivation, and psychosocial characteristics related to friend and family support (as examples) were significant predictors of device use (Scherer et al, 2005). Collectively, the earlier studies of Phillips and Zhao (1993) and the more recent work of Pape et al (2002), Reimer-Weiss and Wacker (2000), and Scherer et al (2005) provide evidence that characteristics of the device, the person, and their environment predict whether the client will use a device or abandon it.

Health-Related Quality of Life.

The concept of health-related quality of life (HRQL) refers to the impact of health services on the overall quality of life of individuals, and it represents the functional effect of an illness and its consequent therapy on an individual as perceived by the person receiving the therapy (Oldridge, 1996). It measures one dimension of quality of life. Others are independence, income, adequate housing, and a safe environment. The definition of HRQL is “the value assigned to duration of life as modified by impairment, functional states, perceptions and social opportunities that are influenced by disease, injury, treatment or policy” (Patrick and Erickson, 1993; quoted by Oldridge, 1996). Rehabilitation in general, and assistive technologies in particular, addresses the long-term effects of disease and injury. Therefore both rehabilitation and assistive technology affect HRQL as defined here. However, as Oldridge points out, there are many instruments that have been developed to measure HRQL. Many of these are medically oriented and unsuited to assistive technology outcomes measurement. However, the general concepts underlying HRQL do have relevance to assistive technology outcomes measurement, and there is a need to develop new instruments that are more sensitive to the impact of assistive technologies on HRQL. Oldridge (1996) describes the types of HRQL measurements, their application, and the underlying principles on which this construct is based.

Psychosocial Impact of Assistive Devices Scale.

To address the need for quality of life–related measures in assessing assistive technology outcomes, Day and Jutai (1996) developed the Psychosocial Impact of Assistive Devices Scale (PIADS). The development of the PIADS was based on information obtained through focus groups on the experiences of users of assistive technology (Day and Jutai, 1996). The initial set of constructs was developed and evaluated by a set of users. The scales were modified to include both positive and negative impacts on quality of life of assistive technology users by defining a scale from −3 (maximal negative impact) to +3 (maximal positive impact). The final version of the PIADS is a 26-item self-rating scale intended to measure the impact of rehabilitative technologies and assistive devices on the quality of life of the users of these products. Three subscales are included in the PIADS. These are competence (the effects of a device on functional independence, performance, and productivity), adaptability (the enabling and liberating effects of a device), and self-esteem (the extent to which a device has affected self-confidence, self-esteem, and emotional well-being). This multidimensional aspect of the PIADS contributes to its reliability and validity as a measure of the psychosocial impact of assistive technologies on the consumer.

The PIADS has been applied to measurement of outcomes with a variety of assistive technologies. The original study focused on eyeglass and contact lens wearers (Day and Jutai, 1996). In subsequent studies it has been demonstrated that the subscales of the PIADS remain consistent over populations and types of disabilities (stroke, amyotrophic lateral sclerosis, cerebral palsy) or types of assistive technologies. For example, Jutai et al (2000) used the PIADS to evaluate the psychosocial impact of EADLs (see Chapter 14). The goal of this study was to determine the perceived benefit of EADLs to the consumer’s quality of life. Two groups were included: users of EADLs and those for whom EADLs were appropriate but who had not yet received them. Users’ perceptions were measured at two points 6 to 9 months apart to determine the stability of the perception of psychosocial impact. Jutai et al found that EADLs produced similar degrees of positive impact on users and positive perceptions of anticipated impact on those without EADLs. The two measures of those using EADLs indicated that the psychosocial impact was stable over the time frame used. This study demonstrated the utility of the PIADS as an instrument for quantifying the psychosocial impact of assistive technologies.

Jutai et al (1996) discuss the use of instruments such as the PIADS to evaluate the outcomes of service provision in assistive technologies. The importance of quality-of-life outcome measures, in addition to clinical, functional, and user satisfaction assessments, is demonstrated through a series of case studies related to ease of implementation, clear definition of the desired outcomes, ethical considerations, and responsibility to the user of the assistive technology.

Matching Person and Technology Model.

The Matching Person and Technology (MPT) model and assessment instruments have been developed to allow consumers to prioritize their own outcomes in relation to measurable changes in the perceived quality of life as opposed to the absence of disease or sickness or functional ability (Galvin and Scherer, 1996). This instrument has much in common with the QUEST and PIADS. The developers of the QUEST used the MPT as one of the theoretical bases for their work (Demers, Weiss-Lambrou, and Ska, 1996). As in these other measures, the MPT is a multidimensional instrument that taps domains related to overall impact on quality of life. Three domains are included in the MPT (Galvin and Scherer, 1996). The milieu dimension assesses characteristics of the environment and psychosocial setting in which the assistive technology is to be used. The personality dimension focuses on the individual’s personality, temperament, and preferences. Finally, the technology component addresses characteristics of the assistive technology itself. Like the QUEST and PIADS, the MPT is designed to be applied across a wide range of disabilities and assistive technology types. The multidimensional nature of the MPT makes it possible to separate influences of the technology, environment, and personal preferences. For example, a consumer may have characteristics (goals, skills, and abilities) typically associated with assistive technology nonuse as measured by the milieu/environment variable but may appear to be an optimal user according to characteristics identified for personality and technology. In this case the milieu/environment influences may need to be addressed before the consumer can gain maximal benefit and satisfaction from the use of the assistive technology. Galvin and Scherer (1996) describe the MPT instrument and its application in detail. The MPT has been shown to have reliability and validity in determining the factors related to device abandonment and in assessing the impact on quality of life of assistive technology use.

1. Finger, hand, and wrist movement

Present hand range sheet. Locate the sheet with the client’s midline centered on square 8.

The squares are numbered and each corner is lettered as shown. The targets are the corners. Use the sequence: touch the square then 1A/1B/1C/1D and repeat for all squares within the person’s range. Circle locations reached. For children, it may be necessary to use the smaller (foot) range sheet.

Compare your impression of the time required to reach the square (tracking time) to the time required to move among the corners A, B, C, D (select time).

Use the distance table (see Figure 4-5) to fill in the following block.

For each movement requested place a (present) or—(absent) in the appropriate column. Note whether required movement can be initiated (I), controlled (C), and terminated (T).

If adequate arm and hand movement are available, omit the following tasks:

D Range: Foot

E Head control

1. Peripheral

    Instruct the person to keep head and eyes fixed straight forward. Ask the person to indicate when he or she can see your finger or pointer without moving his or her eyes. If the person cannot keep the eyes fixed, provide an object to stare at. Start with your finger or pointer approximately 12 inches from the side of his/her head (at the ear) and move it around the head toward the face. Mark the areas in which the person can see your finger.

2. Tracking

    Using your finger or pointer, have the person track horizontally at the level of the eyes. Begin at the nose and go left/right. To track vertically, begin at the nose and go up/down.

1. Instructions

    Select the stimuli according to the information available. If information is lacking, begin with a more “basic” symbol system (e.g., select pictures over words or letters) and begin with the largest size set. Place the stimuli approximately 18 inches from the subject’s eyes. Determine the method of selection and explain it to the consumer.

    Present two stimuli to the consumer and say, for example, “Please point to (look at) the comb,” or “Is this a comb?” Three trials should be run. If no errors are made, the size of the stimuli should be reduced, with three trials run at each size tested. A more advanced symbol system may then be tested if appropriate. If some errors are made, a more basic symbol system should be tested and the positioning of the stimuli should be reexamined.

2. Data sheet

    Use a plus mark in the choice column to designate a correct response and use a circle to designate an error. Be sure to note a symbol system and stimulus size for all trial groups.

    Optimal symbol type: ___________________________________________

    Optimal size: __________________________________________________

    If you were not able to establish an optimal stimulus, explain why.