Perception

Perception is the interpretation of sensory information received through our eyes, ears, and skin, i.e., what we see, hear, and feel.² Perception is a very basic cognitive skill that is integrated with higher-order cognition to achieve various skills, such as sequencing the steps required to make a bed. Impairments that affect perception limit an individual’s ability to use information from the environment to assist her daily activities. For example, someone with reduced visual acuity may have difficulty perceiving text that is presented on a computer screen. In this case, enlarged letters and auditory feedback may aid her when using a computer for word processing.

Attention

Attention is the ability to focus on a particular task.⁵⁰ For example, selective attention refers to the ability to shift attention between competing tasks, which requires selectively attending to one stimulus while ignoring another.²¹ The characterization of different types of attention provides insight into different areas in which people may have strengths and weaknesses and for which assistive technologies may be able to help.

Attention has been characterized by different levels. Any task can involve more than one type of attention. The first of these is the detection or observation of a particular stimulus or signal (e.g., an object or event occurring in the environment). We can detect a signal in two ways. Vigilance refers to paying close and continuous attention over a prolonged period in order to detect a signal. Sustained attention is similar to vigilance, but there isn’t necessarily a competing stimulus present in sustained attention. Search is the active scanning of the environment to find a particular stimulus or particular features. Vigilance and sustained attention require the person to wait for the signal to appear, and search requires the person to actively seek out a target.

Using selective attention, we filter out distractions and focus on the event we have chosen.³ Variability in our selective attention skills is common, especially when there are distractions. For some individuals, the influence of distractions is such that they are unable to focus on a task when another stimulus (e.g., a conversation) is occurring in the background. For example, individuals with attention deficit disorder have difficulty focusing on the teacher in class. There are other situations in which we are required to devote attention to two or more tasks at the same time using divided attention. One example is listening to a lecture and taking notes. Students need auditory attention and processing skills to understand what the teacher is saying, and additionally require visual and tactile skills to take notes. While the activities of listening to a lecture and taking notes appear to be concurrent, in fact attention is moving quickly between the two tasks.

Memory

Memory draws on past knowledge to use it in the present. Short-term memory refers to storage of information for up to about 20 seconds. Various strategies, such as rehearing the information to be remembered, can be used to maintain information in the short-term memory. For something to be remembered for a longer period of time, it is necessary for it to be transferred to long-term memory. In order for memory to be useful, the input must be perceived, recognized as something that is important to retain, encoded, stored, and then retrieved. Memory impairment can occur at any one of these parts of the process.

Two common ways of retrieving information from memory are recall and recognition. Free recall tasks provide virtually no hints at all, while cued recall tasks add in a small amount of information about the material the participant is supposed to recall.⁵⁰ Recognition tasks provide the target (material to be remembered) along with other material meant to distract the person; for example, recognition is often involved in multiple choice questions.

Orientation

A simple walk down the street during lunch hour provides an abundance of information about a noisy construction site, the smell of flowers, or the number of cars waiting at a stoplight. These things, as well as all the other information that we attend to on a constant basis, help us to orient ourselves. Orientation can be interpreted in different ways, depending on the perspective. To someone who works with an individual with a visual impairment, orientation means moving about the environment. For an individual with a cognitive impairment, the link to movement is not required, but it is often an important part of orientation. There are three types of orientation that are important: person, place and situation, and time.

Our awareness of our own identity and that of others in our environment is called orientation to person.⁴⁹ Orientation to person is commonly affected in disorders such as dementia and traumatic brain injury (TBI), where people forget not only who others are, but also who they are. A simple assistive technology that can aid orientation for a person is a card that lists the person’s address and phone number, which can be presented to a passerby if they become lost.

We are constantly made aware of where we are and where we are going by paying attention to clues such as streets and landmarks, or by knowing that home lies east of where we are. More importantly, the ability to guide ourselves from point A to point B using these clues is called orientation to place.⁴⁹ Assistive technology way-finding devices can aid people who have orientation-to-place limitations.

Orientation to time is what permits us to know it is lunch time and that we can go on our daily walk.⁴⁹ For individuals who have difficulty reading standard clocks, there are assistive technologies that provide a sense of when events are to occur and the amount of time that must elapse before the event occurs. Orientation to time is broader than simply the time of day; often the question for an individual is “What day is it?” It also involves orientation to things such as time of year (e.g., certain holidays, which are cues for behaviors and activities).

Knowledge Representation

Knowledge representations help us relate to things, ideas, and events. The mental representation of facts (e.g., “gravity makes things fall”), objects (e.g., our house or car), and skills (e.g., how to wash our hands) is also related to memory. Declarative memory is what allows us to know what an object is (e.g., a ball). Procedural memory allows us to correctly remember a sequence of operations necessary for performance of a task or procedure (e.g., tying a shoe). Both of these can be important in the application of assistive devices to aid cognitive function.

Grouping like items together is important in representing knowledge. Categorization is the basis for ordering and organizing objects based on their characteristics and how they relate to each other. Categorizing of clothes could identify the type of clothing (e.g., socks, pants, or skirts) or the color or the style or many other features. Once we have decided on a set of categories, the objects, concepts, or thoughts can be organized into defined categories by sorting, the second step of organizing. If the objects, concepts, or thoughts to be organized have a numerical relationship, then the sorting task is called sequencing (i.e., placing the items in the correct numerical order). Sequencing could refer to the steps required to set the table, make a bed, or take a bus to work. Assistive technologies exist that can help individuals who have difficulty sequencing.

Problem Solving

Problem solving is the process of working through details of a problem to reach a solution. In the hierarchy of Box 10-1, the first step in problem solving is identification of the problem. If a person has difficulty identifying problems, various devices such as ones that prompt or cue may help.* Judgment is the ability to make sound decisions and recognize the consequences of decisions taken or actions performed. Decision making is the cognitive process of selecting a course of action from defined alternatives. Two types of reasoning are deductive reasoning and inductive reasoning. Deductive reasoning is a process by which an individual tries to draw a logically certain and specific conclusion from a set of general propositions. For example, when using an assistive device that requires touching a screen location (a button) to create an action, the statements “All buttons make something happen when you push them” and “This is a button” lead to the conclusion, “Something will happen if this button is pushed.” Inductive reasoning is a process by which an individual tries to reach a probable general conclusion based on a set of specific facts or observations. This conclusion is likely to be true, based on past experience, but there is no guarantee that it will absolutely be true.²⁶ In assistive technology design the existence of various types of reasoning implies that the steps required for operation of a device must be logical and intuitive from the user’s point of view, not just from the designer’s point of view. For example, a navigational aid designed for someone with intellectual disabilities needs to present information via voice in simple direct commands (e.g., “go to the white building”) rather than in more abstract general terms (e.g., “turn right 45 degrees and walk 20 meters, then turn right 30 degrees”).

Planning is the process of anticipating future events so as to formulate a course of action to achieve a desired outcome. A person’s ability to perform these tasks may be impacted by congenital conditions affecting brain development or by injury or disease. For these individuals, the best approach is often to reduce the number of alternative solutions, make the options clear, and reduce the reliance on anticipation of future consequences of decisions.

Once a problem solution has been derived, the next step in problem solving involves confirming the successful conclusion of the task. The problem solver must evaluate the outcome of his or her actions and determine whether the task has ended successfully, or whether it requires continuation or repetition (called iteration). Generalization is the carry-over of knowledge or skills from one kind of task or one particular context to another kind of task or another context. Knowledge is most likely to be generalized when the conditions under which the knowledge is to be used are very similar to those under which the knowledge was acquired.²⁶

Language and Learning

Language is fundamental to cognitive task representation. Through language and the process of exchanging information, we can express our thoughts, needs, and ideas. Language is a method of communication and is composed of rules (grammar) and symbols, expressed by gestures, sounds, or writing. When teaching a skill or task, language is used to portray the desired outcome. Learning is the process by which knowledge, skills or attitudes are acquired and it can be attained through study, experience or teaching. In Figure 10-1 we have placed learning at the end of the hierarchy because we believe it builds upon the previously mentioned skills, like building blocks. General learning refers to the basic ability to acquire the knowledge, skills, or attitudes that are necessary for the more specific types of learning: mathematics, reading, and writing. The ability of someone to learn and comprehend in each of these categories helps define both the features the assistive technology must have as well as the skills the person needs in order to use it. Examples of AT for learning are discussed in Chapters 11.

Intellectual disability is typically defined as a disability where one has a below-average score on an intelligence or mental ability test as well as a limitation in functional skills.⁴⁷ These functional skills include (but are not limited to) communication, self-care, and social interaction. The terms developmental disability, cognitive disability, and mental retardation are often used to describe individuals with intellectual disabilities. Intellectual disability can range in severity from mild to severe.

The word dementia comes from the Latin de mens which means “from the mind.” Dementia is best defined as a syndrome, or a pattern of clinical symptoms and signs, which can be defined by the following three points: (1) a decline of cognitive capacity with some effect on day-to-day functioning; (2) impairment in multiple areas of cognition (global); and (3) a normal level of consciousness.³⁹ Dementia is distinguished from congenital cognitive disorders (such as intellectual disability, learning disabilities, etc.) by its age of onset and its degenerative component. It is also important to note that although it affects multiple areas of cognition, not all areas are affected.

Rabins, Lyketsos, and Steele (2006)³⁹ define the “Three pillars of dementia care.” The first is to treat the disease, which helps identify current needs as well as future necessities as the disorder progresses. The second is treatment of the symptoms. By treating the symptoms, the patient’s quality of life will improve in the cognitive, functional, and behavioral domains. Medications and technology are the two main ways to accomplish this task. Third, patient support is important and leads to ensuring that the patient’s needs are met and the quality of life is improved as much as possible.

Stroke

A stroke, or cerebral vascular accident (CVA), is an incidence of irregular blood flow within the brain causing an interruption in brain function. A stroke may arise from a lack of blood flow to the brain (known as an ischemic stroke) or from ruptured blood vessels in the brain (a hemorrhagic stroke).²⁵ The neurological damage incurred as the result of a stroke produces symptoms that directly correspond to the injured area within the brain.³⁸ A CVA causes acute damage to the brain; there are no degenerative effects after the onset of injury. As with TBI, persons who have sustained a stroke often have a recovery period where portions of the brain learn to compensate for damaged areas. Typical cognitive and behavioral difficulties associated with stroke are shown in Table 10-7. Most recovery (as observed by the return to activities of daily living) occurs within 6 months after onset.⁸ The majority of persons with CVA are able to return home following their initial hospitalization period. A summary of discharge locations following hospitalization for stroke is shown in Table 10-8. These data suggest that the number of people returning home following a CVA is increasing, which might be attributed to improvements to hospital care at the onset of stroke. Children may have a more pronounced recovery than adults, as their brains have a greater degree of plasticity. Also, women may display greater recovery of lost language skill than men, as the language centers of the brain are larger in women than in men.⁸

Table 10-7

List of Typical Cognitive and Behavioral Difficulties after Stroke

Type of Difficulty	Examples
Cognitive	Visual neglect, hemianopsia
	Apraxia
	Language problems (i.e., aphasia, dysarthria)
	Perceptual deficits (i.e., figure-ground impairment, disorientation)
	Impaired alertness, attention disorders
	Memory problems, both short-term and long-term
	Perseveration
	Decreased executive function
Behavioral	Impaired judgment
	Impulsiveness
	Emotional lability
	Confabulation
	Poor initiation
	Mood alterations
	Depression

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