Cognitive Responses and Organic Mental Disorders



Cognitive Responses and Organic Mental Disorders


Gail W. Stuart





The ability to think and reason is unique to human beings. Most people fear the possibility of losing their cognitive abilities of reasoning, remembering, and deciding. These functions allow a person to make sense of experience and interact productively with the environment.


Maladaptive cognitive responses leave the affected person in a state of confusion—unable to understand and learn from experience and unable to relate current to past events or to interact reasonably with the people in one’s life. Maladaptive cognitive responses change the way in which individuals think of themselves and the world in which they find themselves, as well as how the world thinks of and relates to them in return.



Continuum of Cognitive Responses


Adaptive coping responses include decisiveness, intact memory, complete orientation, accurate perception, focused attention, and coherent, logical thought. Learning is any relatively permanent change in behavior that results from experience. Learning involves biological changes in the brain that are affected by external environments (the experience of the world in which one is raised) and internal environments (genetic characteristics, developmental events, neurotransmission).


Memory is the storage and retrieval of past experience. Like learning, it is a neurochemical process mediated by the brain. To exercise judgment, make decisions, or even be oriented to time and place, a person must remember past experiences. Therefore, loss of memory is a particularly frightening symptom.


In some people with brain dysfunction, cognitive responses either do not develop fully or deteriorate once they have developed. In general, maladaptive cognitive responses that occur during childhood are called developmental disabilities or mental retardation. This chapter considers maladaptive



LEARNING FROM A CLINICAL CASE


This case can help you understand some of the issues you will be reading about. Read the case background and then, as you read the chapter, think about your answers to the Case Critical Reasoning Questions. Case outcomes are presented at the end of the chapter.



Case Background


His wife was very worried and needed somewhere confidential where she could sort everything out. Her husband was a legislator and a very popular politician. He had helped the county get money for a big highway project and brought industry to their small town when everyone needed jobs. People believed in him and sought his counsel.


But lately she had noticed a change. It was subtle, but she had lived with the man for 40 years. She noticed it over a period of 9 months or even longer. At times she found him standing in one place in the den like he didn’t quite know what to do next. Previously, he really looked forward to his golfing outings and knew his tee-off times by heart. Everything else was scheduled around those commitments. But lately he seemed to get confused about the times and dates. He made other plans and often had scheduling conflicts. That had never happened before. Last night as he drove home, he hit a curb and blew out a tire. He called her on his cell phone to help him decide what to do. He was very agitated. That had certainly never happened before.


When she approached his doctor, he made light of her concerns. She had always been an anxious, hovering wife, and his doctor said he was sure it was nothing. But she felt very protective. Her husband had had an unblemished political record, and she didn’t want anything to happen to tarnish it this late in his life.


Finally she convinced his doctor to refer him to a neurologist. He was sent to a memory disorders clinic and tested. He returned several months later for a follow-up test and scans. The results showed he had Alzheimer disease, a mild form.



cognitive responses in the adult. Although maladaptive cognitive responses may occur at any age, they are most common in the elderly.


Maladaptive cognitive responses include an inability to make decisions, impaired memory and judgment, disorientation, misperceptions, decreased attention span, and difficulties with logical reasoning. They may be episodic or continuous. Depending on the stressor, the condition may be reversible or it may be a progressive deterioration in functioning. Figure 22-1 presents the continuum of cognitive responses.




Assessment


Behaviors


Maladaptive cognitive responses are seen in people who have the psychiatric diagnoses of delirium, dementia, and amnestic and other cognitive disorders. This chapter focuses primarily on delirium and dementia, because these are the psychiatric categories related to cognitive impairment that nurses encounter most often. Assessment relies heavily on biological findings (see Chapter 5) and on the results of the mental status examination (see Chapter 6). Standardized assessment tools also may be useful.


Cognitive activity depends on intelligence, education, life experience, and culture. These can affect cognitive test scores, but not all rating scales or raters of cognitive function take them into account. The nurse should consider that some measures may have these shortcomings when assessing patients with varied abilities and from varied sociocultural backgrounds.



Behaviors Associated With Delirium


Delirium is the behavioral response to widespread disturbances in cerebral metabolism. It should be considered any time there is an acute change in mental status. Although delirium can occur at any age, advanced age is probably the greatest risk factor. It often occurs in hospitalized patients but also can occur after hospitalization and in many cases may result from medications or medical procedures.



Delirium results in disturbances in the following areas:



The patient experiences a reduced awareness of the environment that involves sensory misperceptions and disordered thought (disturbed attention, memory, thinking, orientation) and also disturbances of psychomotor activity and the sleep-wake cycle. These disturbances develop rapidly (over hours to days) and tend to fluctuate over the course of the day, with occasional periods of mental clarity. The disturbances usually worsen at night.


The clinical example that follows illustrates the behavior typical of a patient who is delirious.



CLINICAL EXAMPLE


Ms. S was brought to the emergency department of a general hospital by her parents. This 22-year-old single woman was described as having been in good health until 2 days before admission, when she complained of malaise and a sore throat and stayed home from work. She worked as a secretary in a small office and had a stable employment record. According to her parents, she had an active social life, and there were no significant conflicts at home.


On admission, Ms. S was extremely restless and had a frightened facial expression. Her speech was garbled and incoherent. When approached by an unfamiliar person, she would become agitated, try to climb out of bed, and strike out aimlessly. Occasionally she would slip into a restless sleep. Her temperature on admission was 104° F (40° C), her pulse was 108 beats per minute, and her respirations were 28 per minute. Her skin was hot, dry, and flushed. According to her mother, Ms. S had only a few sips of water in the last 24 hours and had not urinated at all, but she had experienced several episodes of profuse diaphoresis.


Ms. S’s ability to cooperate with a mental status examination was limited. She would respond to her own name by turning her head. When her mother asked her where she was, she said “home,” but she could not say where her home was. She would give only the month when asked for the date and said it was January (the actual date was February 19). She also refused to give the day of the week. A neurological examination was negative for signs of increased intracranial pressure and for localized signs of central nervous system (CNS) disease.


The tentative medical diagnosis was delirium secondary to fever of unknown origin. Symptomatic treatment of the fever, including intravenous fluids, an aspirin suppository, and a cool water mattress, was begun immediately while further diagnostic studies were performed. Nurses caring for Ms. S noticed that she continued to be restless and disoriented and that her speech was still incoherent. They also noticed that she was picking at the bed clothing. Suddenly she became extremely agitated and tried to get out of bed while crying out, “Bugs, get away, get bugs away!” She was brushing and slapping at herself and the bed. As her mother and the nurse talked with her and held her, she gradually became calmer but periodically continued to slap at “the bugs” and needed reassurance and reorientation.


Additional laboratory results became available later in the day. A lumbar puncture was performed, as was magnetic resonance imaging (MRI) of the head; results were normal. Results of a toxicological screening of the blood also were negative. However, the electroencephalogram (EEG) revealed diffuse slowing. In addition, the elevated white blood count and electrolyte imbalance were consistent with severe dehydration. Cultures of Ms. S’s throat and blood were both positive for β-hemolytic streptococci, and intravenous antibiotic therapy was begun at once while other supportive measures were continued.


Ms. S’s mental state improved as the infection gradually came under control and the fever decreased. Her cognitive functioning was completely normal when she was discharged from the hospital, with the exception of amnesia for the time during which she was delirious.



Ms. S demonstrated many behaviors often seen in patients with delirium. These behaviors have a sudden onset and are related to alterations in neurochemical and electrical responses in the brain as a result of the stressor that causes the maladaptive response. Disorientation is generally present and sometimes in all three aspects of time, place, and person. Thought processes are usually disorganized. Judgment is poor, and there is a lack of sound decision-making.


Stimuli may be misinterpreted, resulting in illusions or distortions of reality. An example of such an illusion is the perception that a polka-dot drape is actually covered with cockroaches. Delirious patients may hallucinate. These hallucinations are usually visual and often take the form of animals, reptiles, or insects. They are real to the person experiencing them and are very frightening. Assaultive or destructive behavior may be the patient’s attempt to strike back at a hallucinated image.


At times, patients with delirium also exhibit a labile affect, changing abruptly from laughter to tearfulness and vice versa for no apparent reason. A loss of usual social behavior also may be noted and may result in acts such as undressing, playing with food, and grabbing at others. Delirious patients tend to act on impulse.


Other behaviors may be specifically related to the cause of the behavioral syndrome. For example, Ms. S’s brain syndrome and the fever and dehydration she experienced were a result of her systemic streptococcal infection. It is very important that observations of behavior be described carefully, because this helps identify the stressor.


Treatment is usually conservative until a specific stressor has been isolated. Although most patients recover, it is possible for the person to develop long-term disabilities or to die as a result of the severity of the stressor.


Delirium is commonly found in hospitalized patients, particularly in intensive care units (ICUs), geriatric psychiatry units, emergency departments, alcohol treatment units, and oncology units (Fricchione et al, 2008; Uguz et al, 2010). In addition, a diagnosis of delirium can be missed because the symptoms are assumed to be caused by depression. If adequate intervention does not take place, delirium may become chronic and irreversible.



Behaviors Associated With Dementia


Dementia is a loss of intellectual abilities that interferes with the patient’s usual social or occupational activities. The loss of intellectual ability includes impairment of memory, judgment, and abstract thought. The patient with dementia does not have the clouding of awareness or the rapid onset that is seen with delirium.


The onset of dementia is usually gradual. It may result in progressive deterioration, or the condition may become stable. Personality changes often occur. They may appear either as a change or as an intensifying of the person’s usual character traits.


In some cases the process of dementia can be reversed, and the person’s intellectual functioning improves if the underlying stressors are identified and treated. However, in many cases dementia involves a continual and irreversible decline in mental function and behavior. Reversible causes of dementia are listed in Box 22-1.



Dementia may occur at any age but most often affects the elderly. This condition results from structural and neurochemical changes in the brain resulting from trauma, infection, cerebrovascular disruptions, substance use, or an unknown cause. The various types of dementia are listed in Table 22-1.



Alzheimer disease (AD) is the most common type of dementia and accounts for approximately 70% of cases of the disease. However, AD is not a normal part of aging.


In the United States, early-onset dementia affects more than one-half million people younger than 65 years of age. In younger adults, early symptoms may be mistaken as stress or depression (Hunt, 2011). Dementia forces individuals to assume dependent roles within their families at a time when they may be primary caretakers themselves. Facts and figures about AD are presented in Box 22-2.




The following clinical example demonstrates the behaviors associated with dementia.



CLINICAL EXAMPLE


Mr. B is a 73-year-old widower who has resided in a retirement home for 3 years. He chose to move to the retirement home after his wife’s death even though his son encouraged him to live with him and his family. Mr. B stated that he did not want to burden his family and would be happier with others of his same age. He did well for the first 18 months. He was an active participant in social groups both in the home and in his church, which he continued to attend regularly. He also visited his son weekly and enjoyed seeing his grandchildren.


About 18 months ago, Mr. B began to seem forgetful. He would ask the same question several times and on occasion prepared for church on a Friday or Saturday. He also became irritable and accused his son of not caring about him and of abandoning him in “that place.” Mr. B spent many hours taking papers from his desk and studying them. When asked what he was doing, he would say, “Attending to my business.”


He began to withdraw from activities and make flimsy excuses to avoid playing his favorite card game, gin rummy. When persuaded to play, he usually quit in frustration because he could not remember which cards had been played. Mr. B was quite anxious at times. He seemed well oriented at times and expressed great concern about the changes he was experiencing, wondering if he was “going crazy.”


Because of the concern of the retirement home staff, Mr. B was scheduled for a complete physical examination by his family physician and for a psychiatric evaluation by the geriatric psychiatric nurse consultant who came to the retirement home each week. The physical examination found Mr. B to be in generally good health for a man his age. He had a mild hearing loss and slight prostatic hypertrophy. Hypertension had been diagnosed 10 years before this examination but was well controlled by diuretics. A neurological examination revealed normal reflexes, normal muscle strength, a slight intention tremor, normal responses to sensation, normal cranial nerves, and no disturbance of gait. The results of electroencephalography (EEG) were normal, as were those of laboratory studies of blood and urine. Computed tomography (CT) studies of the brain revealed some atrophy of the cerebral cortex.


The mental status examination confirmed the deficits in cognitive functioning observed by the nursing home staff and Mr. B’s son. Mr. B was oriented to person and place but stated the date as April 6, 1958 (the real date was January 21, 2010). He also thought the day of the week was Friday, and it was actually Wednesday. He correctly identified the season of the year as winter. Mr. B was able to state correctly his birth date, the date of his son’s birth, and the year he began to work at his first job.


He spoke at length and with great detail about his exploits as a young man. His vocabulary was excellent, as was his fund of general information. However, he could not repeat the names of three objects after 5 minutes and could not remember what he had eaten for lunch or the last name of the man who shared his room. He became distressed while trying to answer these questions. He was unable to remember the names of the two most recent presidents but could recite the names of the eight presidents before them.


Mr. B’s judgment was somewhat impaired. When asked what he would do if he found a stamped, addressed, sealed envelope, he said he would “read it, then mail it.” His abstract thinking was concrete, as was seen in his difficulty in interpreting proverbs. His attention span and ability to concentrate were normal. His eye-hand coordination was disrupted, as demonstrated by difficulty in copying simple figures. A hand tremor was evident both when he was drawing and when he was signing his name.


Mr. B’s affect was appropriate to the content of the discussion both in quality and in quantity. He appeared depressed when talking about his memory loss but cheerful and proud when describing his grandchildren. No abrupt mood swings were noted. His flow of speech was of a normal rate and volume. The content of his speech was logical and coherent but became somewhat disjointed when he tried to remember and describe recent events.


As a result of the data gathered in the physical and mental status examinations, Mr. B was diagnosed as having dementia not otherwise specified. Over the next several months his condition continued to deteriorate gradually. He became increasingly forgetful and began to confabulate and fabricate stories. He was less conforming to social norms and needed to be reminded about hygiene and appropriate dress. He also became seductive with female residents and staff, making suggestive remarks and occasionally fondling someone.


Visits to his son’s home became impossible as his behavior deteriorated. His memory of the identity of family members was sometimes confused. He would misidentify his daughter-in-law as his wife and his grandson as his son. His conversation increasingly consisted of rambling reminiscences about his life in his youth. His son and health care providers began to discuss plans to move him to the assisted living program associated with his retirement home. Because he was surrounded by caring people, Mr. B continued to live with dignity and respect despite his progressively limited ability to communicate and to take care of himself.


Selected Nursing Diagnoses




The behaviors associated with dementia reflect the brain tissue alterations that are taking place (Table 22-2). Behavioral change occurs slowly in the early and late stages of AD and rapidly in the middle stage. The three stages of AD are listed in Box 22-3.




Cognitive changes are related to the stressors that interfere with the functioning of the cerebral cortex and the hippocampus. Other areas of the brain also are affected, which is one reason for performing a complete medical and neurological examination.


Another reason is that although dementia is often irreversible, progression may sometimes be stopped or slowed by identifying the stressor and treating the underlying dysfunction. For example, the treatment of hypertension may prevent a further occurrence of one large or many small brain hemorrhages, which are possible causes of vascular dementia.


Depression in the elderly is often misinterpreted as dementia and therefore is not treated appropriately. Pseudodementia is a cognitive impairment that occurs secondary to a functional psychiatric disorder such as depression and is characterized by lapses in memory and judgment, poor concentration, and seemingly diminished intellectual capacity. This condition is reversible with appropriate treatment of the depression.


Depression associated with AD is among the most common mood disorders of older adults. Aggression in patients with dementia is strongly linked to the presence of depressive symptoms. Appropriate treatment of the depression may be a way of preventing and managing the physically aggressive behavior. AD behaviors related to delirium, dementia, and depression are compared in Table 22-3.



TABLE 22-3


COMPARISON OF DELIRIUM, DEPRESSION, AND DEMENTIA


























































































PARAMETER DELIRIUM DEPRESSION DEMENTIA
Onset Rapid (hours to days) Rapid (weeks to months) Gradual (years)
Course Wide fluctuations; may continue for weeks if cause is not found May be self-limited or may become chronic without treatment Chronic; slow but continuous decline
Level of consciousness Fluctuates from hyperalert to difficult to arouse Normal Normal
Orientation Patient is disoriented, confused Patient may seem disoriented Patient is disoriented, confused
Affect Fluctuating Sad, depressed, worried, guilty Labile; apathetic in later stages
Attention Always impaired Difficulty concentrating; patient may check and recheck all actions May be intact; patient may focus on one thing for long periods
Sleep Always disturbed Disturbed; excess sleeping or insomnia, especially early-morning waking Usually normal
Behavior Agitated, restless Patient may be fatigued, apathetic; may occasionally be agitated Patient may be agitated or apathetic; may wander
Speech Sparse or rapid; patient may be incoherent Flat, sparse, may have outbursts; understandable Sparse or rapid; repetitive; patient may be incoherent
Memory Impaired, especially for recent events Varies day to day; slow recall; often short-term deficit Impaired, especially for recent events
Cognition Disordered reasoning May seem impaired Disordered reasoning and calculation
Thought content Incoherent, confused, delusional, stereotyped Negative, hypochondriac, thoughts of death, paranoid Disorganized, rich in content, delusional, paranoid
Perception Misinterpretations, illusions, hallucinations Distorted; patient may have auditory hallucinations; negative interpretation of people and events No change
Judgment Poor Poor Poor; socially inappropriate behavior
Insight May be present in lucid moments May be impaired Absent
Performance on mental status examinations Poor but variable; improves during lucid moments and with recovery Memory impaired; calculation, drawing, and following directions usually not impaired; frequent “I don’t know” answers Consistently poor; progressively worsens; patient attempts to answer all questions


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A common behavior related to dementia is disorientation. Time orientation is usually affected first, then place, and finally person. This can be distressing to the patient, who may be aware of this difficulty and embarrassed or frightened by it. This is particularly true if the person’s mental acuity fluctuates. In these instances the person is aware, during clear periods, of the confusion and disorientation experienced at other times.


Memory loss is another prominent characteristic of dementia. Those with declining memory are often not fully aware of their deficits in activities of daily living (ADLs). A mathematically based memory assessment, the MCI Screen, detects early signs of memory impairment caused by AD and related disorders. The MCI Screen helps justify the importance of regular memory assessments in people older than 65 years of age who have no previous diagnosis of memory disorders.


Memory includes several aspects:



All of these are evaluated during a mental status examination (see Chapter 6).


In the last clinical example, Mr. B had trouble remembering the three objects he had heard named 5 minutes before and what he had eaten for lunch, but he gave accurate dates for significant events earlier in his life. Most aging people dwell on the past, but people with recent memory loss have difficulty shifting to the present and at advanced stages may seem to live in the past. This was demonstrated by Mr. B’s misidentification of his grandson and his daughter-in-law.


Another behavior related to memory loss is confabulation. Confabulation is a confused person’s tendency to make up a response to a question when unable to remember the answer. For instance, when Mr. B was asked whether he knew one of the female residents of the home, he replied, “Of course I know her. I used to play gin with her husband.” Actually, the woman’s husband had been dead for many years, and Mr. B had never met him.


Confabulation should not be viewed as lying or as an attempt to deceive but rather as a way of trying to save face in an embarrassing situation. Mr. B is aware that he should know the answer to the question and gives an answer that seems reasonable, not entirely disbelieving it himself.


It is not unlike the situation in which a person meets an acquaintance and cannot recall the other’s name or where they met. The person acts as if these facts are remembered, hoping that the other will offer clues about their identity. Denial of memory loss also may be related to the effect of dementia on the cognitive abilities needed for awareness of the problem.


As AD progresses, patients often develop aphasia, apraxia, agnosia, and amnesia:



These behaviors are related to the effect of the illness on the temporal-parietal-occipital association cortex.


Vocabulary and general information may be less affected by dementia until its late stages, and recall depends on when the information was learned. Facts learned early in life may be recalled well, whereas those learned recently may be quickly forgotten, as seen by Mr. B’s performance in listing the last 10 presidents.


Patients with dementia may have disturbed sleep, which can worsen memory complaints. They can have labile mood swings, particularly if the limbic system has been affected by the disease process. Some deterioration in social skills may be present as well.


Impulsive sexual advances may occur, reflecting decreased inhibition and impaired judgment as well as deterioration in the limbic system. Often this behavior is an attempt to establish interpersonal contact and is a way of asking for caring from others. It is also a way of reinforcing an important part of the person’s identity—a part that becomes less secure as mental functioning declines.


Alterations in sexual functioning associated with AD cause great concern for patients and their partners. Loss of erection ability is a common problem among men with AD, and it is uncertain whether this is physiological or psychological in origin. However, often both the patient and the sexual partner can benefit from continued sexual intimacy.


Restlessness and agitation are other behaviors that occur with dementia. Extreme agitation may occur at night, a phenomenon known as sundowning syndrome. Sundowning syndrome probably results from tiredness at the end of the day combined with fewer orienting stimuli at night, such as planned activities, meals, and contact with people.



Agitation can be caused by physical and medical problems, environmental stresses, sleep problems, and psychiatric disorders. Each should be carefully evaluated and treated. Disorientation can result in fear and agitation in individuals with cognitive impairment.



The following are precipitating factors related to catastrophic reactions:



The term confusion is often used when referring to a person with cognitive impairment. Although widely accepted as nursing and medical jargon, this term has not been specifically defined. It is better to use specific terms when describing a patient’s behavior. Five types of disturbing behaviors characteristic of dementia are summarized in Table 22-4.



Some people with maladaptive cognitive responses function at a level that is lower than would be expected on the basis of objective measurements of their impairment. This functional deficit is called excess disability.


This problem adds to the frustration of the patient and to the burden placed on caregivers. Caregivers may contribute to the development of excess disability by performing activities for the patient rather than coaching and assisting when needed. Functional abilities are lost more rapidly as the patient becomes more passive in self-care routines.


Patients with a cognitive impairment are often referred to a clinical psychologist for psychological testing. This referral should be made only for a specific purpose, because the testing is time-consuming, expensive, and tiring for the patient. Reasons for psychological testing include measuring the extent of the disability, identifying the stressors causing the disruption, understanding the dynamics of the problem, developing guidelines for therapeutic intervention, and obtaining a prognosis for recovery.



Behaviors Associated with Traumatic Brain Injury


Traumatic brain injury, often referred to as TBI, is a disruption of normal brain function that occurs when the skull is struck, suddenly thrust out of position, or penetrated. Most often it is an acute event similar to other injuries. But it differs in important ways from other injuries. Brain injury can affect all aspects of a person’s life, including personality (U.S. Dept. VA/DoD 2009; SAMHSA, 2010; Reeves and Panguluri, 2011).


No two brain injuries are alike, and each injury manifests in a different way. Symptoms may appear right away, or they may not be present until days, weeks, or months after the injury. The person may not even realize that a TBI has occurred.


The initial trauma tears, shears, or destroys brain tissue. These effects cause secondary injury in the brain including internal bleeding, swelling, oxygen deprivation, and neurochemical changes leading to cell death. A TBI can affect a single, specific region of the brain (focal injury), be distributed throughout the brain (diffuse injury), or both.


On average, an estimated 1.7 million TBIs occur each year in the United States; 52,000 of those experiencing TBI die, 275,000 are hospitalized, and 1.365 million—almost 80%—are treated and released from emergency departments. In every age group, TBI rates are higher for males than for females. Among the age groups that have the highest proportions of TBI are adolescents (aged 15-19 years) and older adults (≥75 years). Sports-related TBIs alone are estimated at between 1.6 million and 3.8 million each year.


For service members in Iraq or Afghanistan, the main TBI risk has been from an improvised explosive device (IED) such as a roadside bomb. Helmets and body armor provide some protection against penetrating head injury and, to a lesser extent, against head-impact events. However, the brain remains vulnerable to the effects of blast waves from IEDs. Gunshot wounds as well as combat- or training-related falls and motor vehicle crashes are other causes of service-related TBI (Snell and Halter, 2010). See Chapter 39 for a discussion of the mental health needs of the military and their families.


TBI is classified into three categories: mild, moderate and severe.



• Mild—A brain injury can be classified as mild if loss of consciousness and/or confusion and disorientation lasts less than 30 minutes. About 75% of all TBIs are mild. Concussion is often used interchangeably with mild TBI. Whereas magnetic resonance imaging (MRI) and computed tomography (CT) scans are often normal, the individual has cognitive problems such as headache, difficulty thinking, memory problems, attention deficits, mood swings, and frustration. These injuries are often overlooked and can be difficult to diagnose.


• Moderate—Moderate brain injury is related to loss of consciousness for more than 30 minutes and less than 24 hours. There may be amnesia for 1 to 7 days related to the injury. Brain imaging may or may not reveal abnormalities.


• Severe—Severe brain injury is associated with loss of consciousness for longer than 24 hours. There is often objective evidence of brain injury on brain scans and neurological examinations. The deficits range from impairment of higher-level cognitive functions to comatose states. Survivors may have limited function of arms or legs, abnormal speech or language, loss of thinking ability, and emotional problems.


The common effects of TBI are listed in Box 22-4. The level and duration of the effects vary from person to person. These effects can be confused with symptoms of other psychiatric disorders.



After TBI, a person is at risk for a range of psychiatric disorders, including depression, generalized anxiety disorder, panic disorder, agoraphobia, and posttraumatic stress disorder (Bryant et al, 2010). About half of all people with TBI also experience chronic pain. These comorbid psychiatric illnesses predict poorer health outcomes and poorer quality of life (Bombardier et al, 2010; Reeves and Panguluri, 2011).



Many people with TBI make a full recovery, but others have long-lasting cognitive and behavioral changes that limit their ability to work and live a functional and productive life. It is estimated that 2% of the population have chronic disabilities resulting from TBI. Multiple TBIs are cumulative in the damage that can occur, so mild cases can become severe.



Predisposing Factors


Maladaptive cognitive responses are usually caused by a biological disruption in the functioning of the central nervous system (CNS). The CNS requires a continuous supply of nutrients, including oxygen, in order to function. Any interference with the provision of supplies to the brain or with the removal of waste products will cause functional disruptions in cognition.



Aging


In 2030, almost one in five U.S. residents, including all of the so-called baby boomers, will be 65 years of age and older. This age group is projected to increase to 88.5 million in 2050, more than doubling the number in 2008. Similarly, the 85 and older population is expected to more than triple, from 5.4 million to 19 million between 2008 and 2050 (U.S. Census Bureau, 2008).


Although aging itself predisposes a person to maladaptive cognitive responses, the loss of mental abilities is not automatically associated with aging. Although a cumulative degeneration of brain tissue is associated with aging, it is not extensive enough to be particularly noticeable in most people.


As people age normally, their cognitive functions slow down but remain intact. If other stressors are added, the person may experience difficulty. Exposure to a toxic chemical or heavy metal, disease, or injury may result in maladaptive cognitive responses, which disrupt normal cognitive responses at any age. However, advanced age is one of the risk factors for dementia associated with AD.



Neurobiological


AD is the most prevalent cause of maladaptive cognitive responses. Intensive research has focused on identifying its causes, characteristics, and treatment (Holcomb, 2008). Investigators have found that characteristic alterations occur in brain tissue of people with AD:


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