The Human Performance Model

The successful use of technology is a product of many interrelated factors. Each factor drives the choices that we need to make. Understanding how these factors interrelate and the effect they have on an individual's performance helps us to filter out ineffective or undesirable AT solutions from the vast milieu of potential devices. Once we have gathered and analyzed the important information, our job is to match the unique set of abilities of the person, the requirements of the tasks they perform regularly, and existing environmental constraints to the characteristics of the available assistive technology devices. The Human Performance Model asks you to gather information about the person, the tasks they must perform, and the environment in which the technology is needed before selecting an AT device. It is imperative that you spend a good deal of time getting to know the person who needs an AT device. This information can come from any number of sources including past records, interviews, observations, and questionnaires.

Here are some things to consider about the person.

1. The Person's Abilities

Knowing about the person's disability is of little use in selecting appropriate AT devices. Yes, the specific areas of a disability that cause the person difficulty helps you to identify goals, but it does not clarify what technology is necessary. The key determiners of which device(s) will help the person comes from a detailed knowledge of the persons abilities. For example, it is more helpful to know that a person can read 24 point type (2x enlargement) than it is to know that they cannot read standard print. The difference between spending your time understanding the disability and identifying abilities is subtle but important.

To understand a person's abilities it is important to gather information about their:

• Sensory abilities - what can they see?, how well can they hear?, can they perceive touch?.
• Cognitive abilities - how does this person think, reason, attend?, are they motivated to work hard or do they give up easily?, how well do they remember information?, can they solve problems?
• Motor - does the person have movement through the full range of motion?, are their movements accurate?, do they have endurance?, how forceful are their movements (particularly pointing)?
• Speech & Language - what kind of receptive and expressive language do they possess?, can they read?, is the person able to interpret gestures or social nuances?, does the person have any idiosyncratic behaviors that communicate messages?
• Social skills - can the person engage in conversational turn taking?, are they aware of non-verbal cues?, what interests does the person have, do they understand the conventions of social etiquette (please, thank you)?

Information about the Person.

1. Preferences/Wants/Needs.
   1. What are your goals (short- and long-term)?
   2. What do you see as your strengths/weaknesses? Preferences (those things that you would enjoy doing or choose to do in your spare time)? Non-preferred activities/items (those things you would avoid if given the choice)?
   3. What do you see as your needs at this time? In the future?
2. Disabilities and Functional Abilities
   1. Tell me a little about how your disability effects your physical abilities, memory and thinking, vision, hearing, and your communication skills.
   2. Is your disability progressive or stable?
   3. If your disability is progressive, what is the short- and long-term outlook?
   4. Tell me a little about your current abilities (what are you able to do physically, thinking and reasoning abilities, vision, hearing, and communication skills)?
3. Prior use of Assistive Technologies.
   1. Have you used assistive devices before? ____ yes ____ no
   2. If yes, what types of AT devices have you used?
   3. Do you still use this device (these devices)?
   4. If no, why are you not using them?
   5. Was the AT successful for you?

2. The Environment

Even when an AT device has all the appropriate elements, the environment may restrict or prevent someone from effectively using a device. Indeed, sometimes the environment is what determines whether a person receives high vs. low technology. The environment refers to a broad array of potential influences in the areas where the person lives, works, and recreates. The physical arrangement of the workstation or home, whether power is readily available, the sophistication of the person's peers or family, and the attitudes of those individuals who will support the person with a disability all contribute significantly to the eventual effectiveness of the AT solution you choose. It is very important that you take the time to thoroughly examine the person's environment(s) and take into account any variables that may inhibit the person's use of an AT device. Once identified, these variables must be accounted for in the AT intervention plan so that abandonment does not occur.

Information about the Environment(s) where the Person may Potentially Use the AT.

1. In what settings would you like to find AT devices to help you?
2. For each environment, describe what types of assistance/support do you current receive (financial, human, etc.), how often is this support available, and who funds this support?
3. If these supports are human, how would you rate their abilities to work with complex technology (those devices that use computers)? Simple devices(typically non-electronic or relatively easy to operate)?
4. Are there any architectural barriers present in these environments (lighting, electricity, space, noise, physical barriers)?
5. Do you envision using the same AT device in all these environments?
6. How do you think others will respond to you when you use an AT device?

3. The Tasks

The tasks a person must perform using an assistive device are the second critical area we must gather detailed information about. For example, knowing that a specific class requires hands on activities or labs, is much more rich than just knowing that the student is in a science class.

All tasks can vary along several dimensions. When considering AT devices, however, it is useful to gather information about three important task properties: the types of tasks the person must perform, the variety of tasks they must perform in a given day, and attributes of each task (how it is done).

• Types - you should be gathering information about the different types of tasks that the person must perform. Typically, these will fall within the traditional categories of mobility, communication, self-help, recreation, computer use, etc. It is also helpful to gather information about the requirements of each task (verbal or reading skills, the ability to move about the work or living area, memory and reasoning skills, visual acuity, demands on the person's attention, and social abilities).
• Variety - it is important to identify the number and frequency of tasks that the person needs the assistance of an AT device. If the person engages in a variety of tasks across time, be alert to the different skills each task requires. Often, task variety exceeds the capability of one device and a system of AT devices must be developed.
• Task Attributes - attend to the frequency, duration, and intensity of each task.
• Frequency - Is this a high or a low frequency task? Does the task occur all day or is it only part of the day? How important is the task to the user?
• Duration - Will the person need to use the device constantly? Is the person comfortable? How does the task duration compare to the person's endurance?
• Intensity - How much effort must the person expend to complete the task? Does the person need to attend throughout the task?

Information about the Tasks the Person must Perform on a Regular Basis.

1. Tell me about the kinds of jobs/tasks that you need to do on a regular basis? (i.e., what kinds of activities do you do daily)
2. Do you have difficulty performing any of these? How important is this task to you?
3. If so, what specifically about the task do you find difficult/impossible?
4. How often do you do this job? (everyday, once per week, occasionally)
5. How long does the task take you to complete?
6. How difficult is the task to perform? Are you tired when you have finished the task?
7. What tasks would you like to be able to do but are unable to perform as a result of your disability?