Attention and Related Functions

Attention is a widely distributed cerebral process that encompasses many interrelated cognitive functions and serves as the gateway of sensory information flow into the brain. At the most basic level, attention requires arousal and alertness. The reticular activating system and associated thalamic nuclei are primarily responsible for this basic level of arousal and alertness. The anterior cingulate gyrus is heavily involved in initiating attention, focusing attentional resources, and developing control. The dorsolateral prefrontal cortex works together with the anterior cingulate in performing the most complex and highest order attentional processes.

After arousal, the hierarchical nature of attention skills that are hypothesized to be successively more complex include sustained, selective, alternating, and divided attention. The ability to sustain attention for increasing lengths of time becomes the first gauge of attentional sophistication. Selective attention is the ability to attend to relevant information while ignoring irrelevant stimuli. Distractibility, a common feature of prefrontal injury, suggests an inability to selectively attend effectively. Alternating attention entails the ability to disengage, switch, and re-engage attention. Divided attention involves simultaneous awareness of 2 or more activities and the ability to switch or alternate attention between those activities. Many neuropsychological tests of attention are multifactorial, requiring aspects, such as motor speed, reaction times, visual and auditory tracking, selective responding, and other capacities. Accurate identification of deficit areas requires careful evaluation of the constituent components of each task.

Orientation, working memory, and processing speed are closely related features of attention. Orientation, the awareness of self in relation to surroundings, requires successful integration of attention, perception, and memory. Questions related to orientation are featured on most mental status examinations. Patients may be asked to state their name, the location, the date, and their circumstance. Orientation is extremely vulnerable to the effects of brain dysfunction. Impaired awareness for time and place is the most common disorientation and typically occurs with widespread cortical involvement, lesions to limbic structures, or damage to the reticular activating system. Impaired orientation is, therefore, strongly suggestive of cerebral dysfunction. Working memory involves immediate awareness of sensory information and the ability to store and manipulate that information temporarily. During working memory processes, information is attended to, organized, manipulated, highlighted, and discarded. Repeating digits forward and backward is the classic test of working memory. Processing speed refers to the rate at which information is perceived and processed and is typically assessed with timed visual motor attentional tasks. It relies heavily on the integrity of cerebral white matter. Working memory and speed of information processing tend to peak in young adulthood and are among the first cognitive abilities to decline with age. Furthermore, measures of working memory and processing speed are 2 of the most sensitive neuropsychological tasks for brain injury of any kind.

In sum, attention is one of the most important cognitive abilities to assess because it serves as a good measure of overall brain functioning. Impaired attention is related to poor safety outcomes in ADLs, driving behavior, medication management, awareness of limitations, decision-making capacity, mobility, and travel away from home. Patients with moderate to severe attentional impairments have difficulty functioning independently and likely require intensive supervision.

Visual Spatial Functioning

Visual spatial functioning is largely a task of the nondominant hemisphere and is interdependent with attentional mechanisms. Visual spatial ability is an integrated perceptual ability that includes visual attention, form recognition, localization of objects in space, visual construction, visual synthesis, and visual organization. Lesions to the right parietal lobe have been associated with impaired understanding of spatial relationships, impaired spatial conceptualization and imagery, visual inattention, tactile inattention, and impaired body awareness. Lesions overlapping into the occipital cortex may give rise to various visual agnosias.

In evaluating visual spatial functioning, it is important to distinguish nondominant hemisphere visual spatial impairment from deficits due to disorders of the eye, oculomotor deficits, and lesions along the primary visual pathway. Neuropsychological measures of visual spatial functioning commonly involve replicating a figure, identifying a spatial relationship, reconfiguring the pieces of an object, locating a hidden object, or recreating a design out of blocks.

Visual attention deficits are among the most commonly impaired aspects of visual spatial functioning and are highly amenable to cognitive rehabilitation. Visual inattention or neglect involves impaired awareness of visual information, almost always to the left side of space, reflecting its common association with right hemisphere lesions. Patients may neglect the left side of their body, disregard people to the left side of space, or even ignore food on the left side of their plate. Visual inattention is tested with line bisection tasks, cancellation tasks, and clock drawing. An impaired clock drawing, with all the numbers lined up on the right side, is a classic sign of visual inattention. Visual inattention is commonly seen in the acute stages of traumatic brain injury or stroke and tends to dissipate quickly. Later neuropsychological testing, however, may reveal residual signs of inattention long after brain injury.

Visual inattention represents one extreme of visual spatial dysfunction, but other, more subtle deficits also have an impact on patient safety. Even mild visual attention deficits are related to accident-prone behavior. For instance, driving and navigation of any kind is heavily dependent on visual attention, depth perception, form recognition, and localization of objects in space. Accidents, falls, getting lost, and taking the wrong medications may also result from poor visual spatial functioning.

Language

Language is a means of processing and transmitting information, organizing sensory perceptions, codifying thoughts, and expressing emotions. The development of language does not require speech or even audition as evidenced by deaf and/or mute individuals who communicate with sign language. Perhaps more than any other cognitive ability, the acquisition of language is influenced by sensitive and critical periods of development. Individuals who do not acquire language during these periods have marked impairments in cognition. The left hemisphere is dominant for language in approximately 95% of right handers and 70% of left handers. Overall, approximately 96% of the population is left hemisphere dominant for language. Therefore, patients with damage to the left hemisphere should always be closely evaluated for language deficits.

Clinical evaluation of language commonly includes observation of spontaneous speech, verbal comprehension, repetition, confrontation naming, verbal fluency, reading, and writing. Assessment includes open-ended questions to evaluate aspects of speech and content, accuracy of command following, repetition of simple phrases, naming of common objects, reading a magazine or newspaper, and writing one’s name. Bedside language examination can detect obvious aphasias but may fail to identify more subtle deficits because many tasks are routine or overlearned. More detailed language testing and aphasia examinations can be done in collaboration with neuropsychologists and speech therapists.

There are many safety concerns related to deficits in language expression and comprehension. Expressive aphasias preclude patients from communicating medical history and current symptoms, making their needs known, and calling for help in emergency situations. Receptive aphasias limit a patient’s ability to understand medical results, care instructions, and medication regimens. Language is a core cognitive ability that is responsible for all verbally mediated information processing. Inner self-talk is central to many attention and executive functions, such as evaluating, planning, organizing, self-awareness, and decision making. When language is impaired, patient safety and independence is compromised in many ADLs.

Memory

Memory is a multifaceted process that requires encoding, storage, and retrieval of sensory information. At its most basic level, memory requires attention to the environment. Working memory represents the initial processing stage of memory as attentional information is transferred to a more immediate storage in the hippocampus. Working memory and immediate memory are commonly referred to as short-term memory. The left hemispheric hippocampus is primarily responsible for immediate verbal memory. Damage may lead to deficits in learning new semantic information. The right hemispheric hippocampus is more responsible for the immediate visual and perceptual components of memory, such as episodic and emotional features. Damage may lead to impaired recall of complex visual and auditory patterns that cannot be easily verbalized. Long-term memories are not stored in the hippocampus but rather distributed throughout the cortex, especially the temporal lobes.

Long-term memory consists of 2 broad aspects of memory, declarative (explicit) and nondeclarative (implicit) memory. Declarative memory is conscious learning and recall of events and facts, of which episodic memory and semantic memory are 2 subtypes. Declarative memory depends on intact functioning of the temporal limbic structures and interconnected cortical regions. Episodic (autobiographic) memory involves recall of verbal and visual information, details of when and where, and information associated with personal experiences and events. Semantic memory is recall of verbally stored facts and knowledge. Well-learned semantic facts are stored in a diffuse cerebral network and tend to be more resistant to aging, damage, and disease. Conversely, episodic memory is more likely to decline with age. Nondeclarative (implicit) memory is memory for skills and habits and unconscious learning and recall more generally. Procedural memory, priming, classical conditioning, and operant conditioning represent nondeclarative memory abilities. Most nondeclarative memory abilities remain intact in normal aging and even the early stages of Alzheimer disease.

Assessment of verbal memory typically involves recalling varying amounts of words or a story both immediately and after a delay of 5 to 30 minutes. Visual memory tasks require immediate or delayed recall of a picture, spatial arrangement, or design. Early assessment of memory impairment is important because it serves as a baseline from which to compare future findings. Serial assessment is particularly relevant in identifying and staging mild cognitive impairment and dementia. Because memory is so vital to everyday functioning, memory impairment has a significant impact on safety in ADLs, medication adherence, driving, decision-making capacity, and travel away from home.

Executive Functioning

Executive functioning is variously defined, but is generally thought to include the ability to plan, organize, sequence, shift, strategize, execute, inhibit responses, form goals, reason abstractly, monitor thought processes and behavior, perform searches, and allocate resources. Because of the heterogeneity of these functions, many dislike the umbrella term, executive functioning ; however, the term prevails in the common nomenclature. The prefrontal cortex initiates and coordinates cognition and acts as an executive or supervisory system overseeing cognitive processes and operations. Prefrontal systems become very active when a person performs a novel task by integrating information from its 3 main divisions: the dorsolateral, orbitofrontal, and anterior cingulate cortices. The prefrontal cortex is susceptible to injury from head trauma and vascular damage. Damage to the prefrontal cortex does not necessarily lead to executive dysfunction. Furthermore, lesions to areas outside of the prefrontal cortex and the cerebellum can also cause executive-type impairments.

Blumenfeld identifies order, restraint, and initiative as the 3 higher cognitive functions of the prefrontal cortex. Order is processed in the dorsolateral prefrontal cortex and includes abstract reasoning, working memory, perspective taking, planning, insight, sequencing, and temporal organization. Restraint is an orbitofrontal function that entails judgment, foresight, perseverance, delaying gratification, inhibiting socially inappropriate behavior, self-monitoring, and decision making. Initiative involves curiosity, spontaneity, motivation, drive, creativity, shifting cognitive set, mental flexibility, and aspects of personality. Initiative is a function of the anterior cingulate gyrus and interaction of the anterior cingulate and dorsolateral prefrontal cortices. Mateer’s model of executive functioning includes 6 key components, including initiation and drive (starting behavior), response inhibition (stopping behavior), task persistence (maintaining behavior), organization (organizing actions and thoughts), generative thinking (creativity, fluency, and cognitive flexibility), and awareness (monitoring and modifying one’s own behavior).

The executive functions are the most complex and difficult cognitive domain to evaluate and identify. Many individuals with executive impairments perform well on structured tasks, such as IQ tests, but have difficulty with unstructured real world activities. It is, therefore, useful to interview friends or family members regarding executive-type changes in cognition and behavior. Neuropsychological tests of executive functioning measure features, such as complex attention, fluency, novel problem solving, and decision-making ability. No single test, however, effectively captures the broad spectrum of executive disturbance.

Executive functioning may be the strongest of all cognitive domains in the prediction of everyday independent functioning. Executive impairment does more to determine the extent of community reintegration than does damage to any other cognitive system. Many patients with executive impairments demonstrate problems with organization and execution of everyday action, such as errors performing a sequence of action, with the potential for poor safety outcomes. Executive disruption is associated with impairments in ADLs, difficulty organizing medication regimens, motor vehicle accidents, impaired awareness of deficit, decision-making capacity, and decreased independent functioning necessitating supervision.

Instrumental Activities of Daily Living

ADLs are typically divided into 2 types, basic ADLs (BADLs) and instrumental ADLs (IADLs). BADLs include things related to basic self-care, such as grooming, dressing, feeding, toileting, and bathing. IADLs involve more complex tasks instrumental to successful day-to-day functioning, such as shopping, cooking, money management, medication management, communication skills, handling transportation needs, and community activities. Although physical and cognitive deficits interact to decrease effectiveness in performing ADLs in general, BADLs tend to be more significantly impacted by physical factors and IADLs more significantly affected by cognitive impairments. Furthermore, IADLs are necessary to maintain a household as well as safety and independence and tend to precede impairment in ADLs. The capacity to execute ADLs is typically assessed by physical and occupational therapists, whereas neuropsychologists are commonly asked to collaborate in the prediction of IADL functioning. There is a significant association between neuropsychological test performance and the ability to carry out IADLs. Neuropsychological performance has been associated with IADLs in multiple rehabilitation groups, including individuals with traumatic brain injury, heart transplantation, vascular dementia, Alzheimer disease, HIV, and schizophrenia as well as community-dwelling older adults. There are safety issues inherent in many IADLs related to cooking and leaving appliances on; leaving the house and getting lost or injured; taking medication properly; driving or coordinating transportation; organizing important activities, such as doctor’s appointments or pharmacy visits; and dealing with emergencies.

Executive functioning is often at the core of impairments in IADLs. Patients with brain injury typically fare better when performing routine tasks in familiar environments, without distraction, and in the presence of overlearned situational cues. New environments and novel tasks present safety hazards to those with cognitive impairments. Increased frustration and psychological distress can be disorganizing for patients with brain injury and limiting exposure to stressful environments may reduce potential dangers. Functional impairment and safety concerns increase with degree of cognitive impairment necessitating supervision.

Patient and family educational support is central to reducing safety risks in IADLs. Patients and families must be made aware of IADL limitations to make necessary adjustments in supervision needs or find strategies to compensate for IADL deficits. Cognitive rehabilitation has shown effective in improving executive dysfunction and IADL performance, thereby reducing safety risks. There is substantial evidence to support interventions for attention, memory, social communication skills, executive function, and comprehensive-holistic neuropsychologic rehabilitation after traumatic brain injury. Compensatory strategies, such as memory books, calendars, smart phones, and alarming devices, assist in increasing independence in IADLs. These strategies have greater use with low-risk activities, such as keeping appointments, going shopping, and paying bills. IADLs of higher risk (ie, medication adherence and driving) deserve greater scrutiny in ensuring safety and are discussed in the following sections.

Medication Adherence

Medication adherence is broadly defined as the accurate use of medication. This includes proper administration of medicine in the correct dosage, at the appropriate time, and in agreement with any special instructions. Rates of medication compliance are lower than 50% in most studies and tend to decline over time in almost all chronic diseases. Medication nonadherence is associated with declines in overall health and increased risk of hospitalization, increased morbidity and mortality, and higher health care costs. Approximately 10% of hospital admissions are directly attributable to nonadherence with prescription drug regimens, and 23% of nursing home admissions are seen secondary to poor compliance with medical regimens. Medication nonadherence is particularly prevalent in patients who require compliance, such as those with complex medical problems and geriatric patients. Approximately 90% of patients over age 65 regularly take some form of medication, and inappropriate drug discontinuation occurs in up to 40% of this population. As many as 20% of older adults commit medication errors that potentially have serious health consequences. Nonadherence increases with number of drugs prescribed, number of side effects, and overall complexity of instructions and medication regimen.

A prominent cause of medication nonadherence among older adults is related to memory difficulty. Patients with dementia may have difficulty remembering which medications they are taking, when to take the medications, the names of the medications, and even the reasons for their use. Executive functioning deficits contribute to difficulty in adhering to demanding or complex medication regimens, such as those seen in older adults and in patients with multiple medical problems, HIV/AIDS, and cancer. Patients with executive functioning deficits may even perseverate on medication taking and unintentionally overdose. Poor comprehension of medication instructions and medication regimens may play a role in medication nonadherence. Visual impairments and presentation of written instructions can also affect adherence.

Medication adherence is vital to patient health and safety. Increasing adherence involves many factors and application of multiple methods. Factors associated with increased medication adherence include intact cognitive functioning, greater psychological stability, less drug or alcohol abuse, greater familiarity with medication, beliefs about medication effectiveness, few side effects, health literacy, the establishment of routines and regimens, and social support. There are several methods to help increase medication adherence in patients with cognitive impairment. Physicians should provide a thorough explanation of medication instructions at an appropriate cognitive level to patients, inform and bring together a patient’s family and social supports, discuss cost/benefit analyses when appropriate, review side effects, encourage and provide detailed responses to patient questions, have patients repeat verbal instructions, and provide written instructions. They can develop a simplistic medication schedule that matches a patient’s daily routine or specific times of the day that become associated with taking the medication. Pillboxes are an effective external memory aid for patients with impaired memory. These should be kept in the same routinely accessed location, such as by the sink in the bathroom or kitchen. Calendars, erasable boards, and notepads located on a refrigerator with written instructions and daily plans are effective if routinely used. Daily planners, medication charts, pill alarms, and alarms programmed into phones or watches help improve planning, organization, and memory. Limiting the number of medications may increase compliance and reduce medication regimen complexity. Cognitive rehabilitation techniques improve cognitive impairments, and providing education about adherence techniques may be particularly helpful. Discharge education groups for rehabilitation inpatients are effective when medication adherence is discussed and informational materials are distributed. Written instructions in large fonts and simple language may improve comprehension and visual impairments. Medication nonadherence is complex and results from a unique combination of cognitive, emotional, and behavioral factors that dictates subtle tailoring of treatment recommendations to each patient. Therefore, it is important to identify cognitive risk factors associated with nonadherence and recommend multiple methods that are known to increase adherence.

Driving a Motor Vehicle

Cognitive abilities determine driving behavior and safety errors, which in turn predict accidents. Cognitively impaired individuals as a group perform significantly worse than controls on driving measures and the risk of crashes and injury increases with degree of cognitive impairment. Safe driving requires the coordination of motor responsivity, attention, visual perceptual ability, executive functioning, and memory. These abilities are impaired by physical and mental fatigue, drugs and alcohol, advancing age, medical complications, neurologic disorders, and psychiatric disorders. Any disorder affecting vision or perception can have a negative impact on or preclude driving. A certain level of muscular strength and psychomotor reactivity is necessary for safe driving. Patients with sleep disturbances, drowsiness, and fatigue are at increased risk for crashes. Alcohol and drug use increase the risk of automobile accidents exponentially. Furthermore, prescription drugs, such as opiates, anticonvulsants, antidepressants, antihypertensives, antilipemics, hypoglycemic agents, and sedatives, have all been associated with an increased risk of car accidents. To safely operate a motor vehicle requires a higher level of functional ability and integration than any other activity of daily living.

Attention and executive functioning are often cited as the most important cognitive abilities related to driving. Safety issues relate not only to vigilance in rapidly shifting environmental conditions but also to whether or not an individual has the cognitive capacity to recognize slowly changing environmental conditions, such as knowing to watch out for children in a school zone or taking an alternative route if a road is blocked. More specifically, performances on measures of tasks of processing speed, working memory, selective attention, shifting attention, and divided attention have shown a strong relationship to driving performance in patients. Distractibility by electronic devices, competing stimuli, and rapidly shifting environments is particularly treacherous. As attentional complexity and environmental demands increase, the risks for dangerous driver errors and crashes increase. Impaired decision making is another critical factor in driver errors that lead to vehicular crashes. Poor impulse control, such as thrill seeking and aggression, is closely related to decision making and influences driving outcomes. Other emotional and behavioral problems, such as increased stress, depression, anxiety, and psychosis, can have a negative impact on driver performance. Driving safety declines in all forms of memory impairment. Although global positioning system devices assist with navigation, they easily divert attention and are not always accurate. Therefore, routine and alternative routes home should be memorized to prevent getting lost.

Physical capabilities, cognitive ability, and personality characteristics all contribute to safe driving and are highly individualized. Patients with physical impairments that prevent safe driving should be given assistive devices or discontinue driving. The research literature indicates that patients with moderate to severe cognitive impairment should not drive. It is more common, however, to be faced with decisions about patients with milder cognitive deficits that are more difficult to predict. Cognitive rehabilitation may improve cognitive ability related to driving, particularly if safe driving is one of the goals of the therapy. Specifically, speed of processing training has been associated with reductions in dangerous driving maneuvers. Patients may be referred for more intensive driving testing, such as drive simulators, and/or asked to pass state driving tests for licensure. Although it is prudent to recommend discontinuation of driving when there is any concern for patient safety, allowing a patient with cognitive deficits the opportunity to demonstrate capacity and safety in driving through specialized occupational therapy evaluations and/or behind the wheel evaluations conducted by authorized driving schools allows greater levels of independence.

Impaired Awareness of Deficit

Impaired awareness of deficit is a common result of acquired brain injury, which produces significant barriers to patient recovery and presents unique challenges to rehabilitation clinicians attempting to maximize patient safety. Up to 45% of patients with moderate to severe traumatic brain injury demonstrate awareness deficits. At the most extreme, impaired awareness of deficit manifests as anosagnosia, literally translated to “no knowledge of disease.” Anosagnosia is a surprisingly frequent feature of brain injury. Up to 18% of acute hemiparetic stroke patients show unawareness of their paretic limb. Patients with a limited understanding of the nature, degree, and impact of their impairments may be resistant to therapy and engage in dangerous activities because they do not appreciate their limitations. A generalized impaired awareness is often observed in rehabilitation patients with traumatic brain injury, schizophrenia, and dementia. Focal lesions cause specific types of impaired awareness for motor, sensory, visual, and linguistic deficits. Examples include impaired awareness of hemiparesis and hemiplegia, left inattention, impaired awareness of partial or complete blindness, and impaired awareness of disordered speech.

Impaired awareness is most closely related to executive dysfunction, specifically working memory and self-monitoring deficits. Episodic memory deficits may also be related. Some individuals accurately assess their physical status but are much less reliable in their assessment of their cognitive, emotional, and behavioral skills. Individuals with traumatic brain injury are much less likely to complain of changes in personality, such as impaired judgment, reduced insight, irritability, impulsivity, affective instability, and problems with interpersonal functioning in general.

Impaired awareness of deficit may be attributable to psychological denial, neurologic damage, or some combination of the two. Behavioral signs related to defensive or nondefensive methods of coping help distinguish these patients. Denial is defined here as an adaptive psychological defense mechanism that spares an individual from the emotional pain of acknowledging deficits. When evidence for limitations is brought to the attention of an individual with denial, it is not uncommon for the individual to give momentary recognition followed by an explanation that discounts the feedback. Sentences that begin with “Yes, but…” are common in patients who use denial. When pressed, these individuals may become irritated and agitated. Unawareness due to neurologic injury is usually found with damage to the nondominant prefrontal, insular, and/or parietal cortices. In contrast to individuals with psychological denial, patients with a neurologic basis for their impaired awareness may seem puzzled or show indifference when given feedback about their impairments. In cases of pure anosagnosia, by definition, there is no defensive reaction.

In assessment of awareness deficits, the most common strategies include a patient’s self-report of abilities and disabilities, comparison of a patient’s self-report and other observers’ reports, observing a patient’s response to deficits and limitations, observing a patient’s use of compensatory strategies, and comparing a patient’s prediction of performance with the performance on physical examination and cognitive testing.

Many different approaches have been attempted to increase the level of awareness in individuals with brain injury. These include patient and caregiver education regarding unawareness in the context of brain injury, activities designed to highlight limitations and deficits, exploring discrepancies between patient and observer reports, reviewing medical records, and videotaping individuals with brain injury to provide feedback regarding their behavior. The most important early intervention is development of a therapeutic alliance. In the presence of a trusting therapeutic relationship, an individualized treatment plan that moves from simple awareness tasks to more complex awareness tasks can be developed and implemented. These hierarchically ordered exercises help patients experience errors and changes in their ability to increase their awareness about the nature and degree of these changes. This helps initiate patient discussion integrated with clinician education. The rehabilitation plan is more likely to be successful if it is engaging and interesting to patients. In patients with denial or a combination of denial and organically based impaired awareness, an educational approach may be most appropriate. Coordination of a multidisciplinary team of physical therapists, occupational therapists, neuropsychologists, and speech therapists is necessary in more complex cases, such as anosagnosia for hemiparesis and hemiplegia, blindness, or aphasia. Patients whose beliefs are less rigid may be more responsive to feedback and therefore have a better prognostic profile.

Decision-Making Capacity

Capacity is a clinical term used in evaluation of an individual’s ability to make decisions in specific areas, including managing financial affairs, entering into contracts, making a will or advanced directive, consenting to medical treatment, participating in research, driving, and living independently or selecting a living situation. A capacity assessment may be performed by any licensed physician but is usually performed by a psychiatrist or psychologist. Capacity is often confused with the term, competency . Competency refers to a legal determination, made by a judge, of an individual’s ability to retain decision-making power regarding a particular activity or set of activities.

Capacity relates to safety in several areas of patient functioning and along the spectrum of treatment continuum. For example, during acute hospital care or acute rehabilitation, capacity may need to be assessed when a patient is asked to consent to medical procedures or agree to take a prescribed medication. At this level of care, capacity may be questioned at time of discharge when making plans about a living situation, the ability to live alone, or the level of supervision needed. Once a patient is living in the community, the ability to drive, manage finances, and enter into contracts is of greater concern.

Outcomes of capacity evaluations can have serious consequences in a patient’s life, especially if it is determined that an individual does not have capacity. For example, patients may be placed in a nursing home against their will. No one wants to restrict individual freedoms, yet there are potential safety consequences when someone who does not have capacity is allowed to go home without adequate supervision.

Capacity is rarely a dichotomous, static clinical finding. It can change over time as a person’s status improves or deteriorates. For example, medical decision-making capacity was found to improve in patients with traumatic brain injury over a period of 6 months. In some situations, capacity is enhanced by compensating for a patient’s sensory impairments (visual or auditory), communication barriers (aphasia, dysarthria, foreign language, and others), or fatigue limitations. The presence of cognitive impairment in itself does not constitute proof of impaired capacity. Capacity is most closely associated, however, with memory, comprehension, and executive functioning.

Decision-making capacity involves assessment of a patient’s ability to understand and appreciate a given decision. Several interrelated factors evaluated in decision making include the ability to communicate a choice, appreciate the consequences of the choice, reason about the choice, provide a rational explanation of the choice, understand the context in which the choice was made, and know the inherent risks, benefits, and alternatives. Capacity to consent to medical care involves assessment of an individual’s ability to understand the significant benefits, risks, and alternatives to proposed care and to make and communicate a health care decision.

The framework for capacity evaluations involves the following: legal standards, functional elements (BADLs and IADLs), diagnosis (temporary vs permanent and prognosis), cognitive underpinnings, psychiatric or emotional factors, values (race, ethnicity, culture, gender, sexual orientation, and religion), risk considerations, and steps to enhance capacity. Capacity is assessed through informal means, such as observing an individual and/or clinical interview with the individual, family, and treatment staff, and by using cognitive tests and functional assessment instruments. Some of the more commonly used capacity instruments include the Adaptive Behavior Assessment System, Aid to Capacity Evaluation, Capacity Assessment Tool, Financial Capacity Instrument, and Independent Living Scale. Formal testing has the advantage of greater inter-rater reliability, but capacity evaluations are best conducted using a combination of informal and formal testing procedures.

Substance Abuse

It is not yet known whether traumatic brain injury itself increases the risk for substance abuse. Research suggests that a younger age, male gender, substance abuse history and psychiatric history are significant factors in determining risk for substance misuse following brain injury. For individuals with a history of substance abuse, there is likely a decline in use for the first year, but many return to their preinjury level of use 28 months after the injury, a factor that can increase the risk for future head injuries. Limited consistent support systems, poor access to health care, difficulty adjusting to functional changes, avoidant coping strategies, and deficits in executive functioning also increase the risk for substance use.

Premorbid substance abuse history is linked to aggressive behaviors up to 6 months after a traumatic brain injury. Alcohol or drug use at any point postinjury can be harmful and compound the effects of a traumatic brain injury, especially during the first several years when the brain is recovering. Individuals with brain injury may have a lower tolerance to substances due to the presence of fewer neurons to absorb the alcohol or drug and postinjury prescription medications interfering with alcohol/drug absorption. Substance use inhibits new connections between neurons, complicates existing medical conditions, and interacts with prescription medications to create new medical problems. Drug use can exacerbate problems with cognition and increase the risk for seizures and falls that can lead to a subsequent trauma and additional brain damage. It is, therefore, important to recommend abstinence from alcohol and illicit drugs after any acquired brain injury. It is also essential for all clinical staff to inquire about alcohol and drug use, past and present, for several years after a brain injury. Those who are abusing substances or at risk for substance abuse may benefit from support groups and psychotherapeutic interventions. Inpatient treatment may be necessary in more extreme cases.

Suicide

The experience of traumatic brain injury and the related cause often precipitates a complex series of medical, cognitive, and emotional experiences leading to an impaired ability to cope. Persons with traumatic brain injury carry a 4-fold greater risk of committing suicide than the general population. Individuals with brain damage frequently have co-occurring conditions that increase the risk of attempted or completed suicide, such as chronic disease, chronic pain, substance abuse, and psychiatric disorders. Curry outlined several critical suicide risk factors in depression, including a history of suicide attempts, acute suicidal ideation, severe hopelessness, attraction to death, family history of suicide, acute overuse of alcohol, and loss/separations. The highest risk group was found to have suicidal ideation, intent, a plan, a means to lethality, and the fewest inhibitors (reasons not to complete the act). It is, therefore, imperative to assess the risk level of suicidality/homicidality by asking a patient about thoughts of suicidality/homicidality, any potential plans of action, and access to lethal means. Patients with increased risk for suicide may need to be treated in an inpatient psychiatric setting to ensure safety.

Falls

Falls are the second most common source of traumatic brain injury in any age group, behind motor vehicle accidents, and the most common cause of traumatic brain injury in the elderly. Up to three-quarters of older adults with cognitive impairments or dementia fall each year and the number of falls increases with degree of dementia severity. Fatalities as a result of fall-related traumatic brain injury are most common in those over age 75. Disorders affecting the frontal lobe, subcortical structures, and cerebellum are associated with an increased risk of falls.

Falls occur because of an interaction of environmental factors, medical problems, and cognitive impairment. Miller and colleagues describe 4 common issues that have been implicated in increased risk for falls in the elderly. These include postural hypotension, gait and balance instability, polypharmacy, and the use of sedative medications. Sedative use impairs attention and is a major risk factor for falls. Hyperactive symptoms are an additional risk factor associated with falls. The role of visual perceptual disturbances is apparent in falls. Impairments in attention, memory, and executive functioning have also been linked to falls. Processing speed is linked to various indices of mobility as well as falls in older adults. Depression also increases the risk for falls in older adults.

Interventions to improve cognitive function may be helpful in reducing falls among older adults. Educational efforts can be beneficial in preventing falls. The Brain Injury Association of America suggests that physical conditioning, review of medications, use of comfortable and gripping shoes, and modification of the environment reduce falls in older adults. Modification examples include reducing waxed or slippery floors, decreasing potential hazards in the bathtub or shower, removing loose rugs, removing or altering sharp furniture and potential snags, and increasing the amount of light in and outside the house. One study showed that modification of the environment decreased falls by 60% annually.

Wandering

Individuals with cognitive impairment are at a higher risk for harm due to wandering, which occurs as a result of disorientation, confusion, and memory dysfunction. The Alzheimer’s Association estimates that 60% of individuals with Alzheimer disease wander and become lost at some point. These incidents may result in injury or death due to hyperthermia, drowning, and dehydration. Wandering can be reduced using behavioral measures and environmental modifications. Behavioral measures include supervision, keeping a person oriented, and avoiding complicated tasks and changes in routine. Environmental modifications include keeping the house layout consistent and familiar, setting boundaries of travel, and controlling exits.