Journal of Gerontological Nursing

DIAGNOSTIC DILEMMA: Cognitive Impairment in the Elderly

Marquis D Foreman, PhD, RN; Regina Grabowski, MS, RN

Abstract

Cognitive impairment is a significant problem for the elderly. Historically, cognitive impairment and aging have been considered synonymous. Current attitudes and thoughts of aging are more enlightened: cognitive impairment is no longer perceived as a "benign" and inevitable concomitant of aging but as a condition that warrants prompt and aggressive action. For this action to be efficacious, the specific nature, or type, of the cognitive impairment must be identified precisely. In other words, it must be determined accurately if the condition is an acute confusional state, dementia, or depression - a distinction that is not always readily apparent.

Acute confusion, also known as delirium, transient cognitive impairment, ICU psychosis, and several other names, is a prevalent condition occurring in as many as 80% of elderly patients hospitalized for acute physical illness (Foreman, 1990). An acute confusional state is a simultaneous disturbance in consciousness, attention, perception, memory, orientation, thinking, psychomotor behavior, and the sleep-wake cycle (Foreman, 1991). These symptoms of acute confusion develop abruptly over a period of hours and tend to fluctuate diurnally.

Acute confusion is associated with increased morbidity (Weddington, 1982), increased intensity of nursing care (Williams, 1986), longer hospitalization (Lipowski, 1983; Weddington, 1982), increased rates of nursing home placement on hospital discharge (Levkoff, 1986; Lipowski, 1983), and increased mortality (Weddington, 1982). All of these factors contribute to the increased per day hospital costs associated with providing care to acute confused older patients. Levkoff and colleagues (1986) estimated that reducing the length of hospitalization by just I day would save Medicare $1 to $2 billion annually.

Dementia is a chronic, insidious, progressive, and permanent form of cognitive impairment. It is an impairment of higher cortical functions, including memory, that is manifested by difficulties in day-to-day functioning, problem solving, and in the control of emotions (Bondareff, 1986). Currently, dementia is estimated to affect 1 to 5 million Americans (Office of Technology Assessment, 1987). It is projected that by the year 2040, dementia will affect 7.4 million Americans (Office of Technology Assessment, 1987). Although dementia has no known cure, in many instances the cognitive decline associated with dementia can be slowed or even halted.

Depression is frequently referred to as pseudodementia and pseudodelirium because of the similarities in the clinical features among delirium, depression, and dementia (Blazer, 1989a). As a mood disturbance consisting of dysphoria, feelings of sadness, pessimism, hopelessness, and loss of interest or pleasure in most activities (American Psychiatric Association, 1987; Staab, 1990), depression is the most frequent psychiatric disorder of old age (Kane, 1984). Of community-residing elders, 2% to 14% have major depression, whereas approximately 15% have mild depression (Blazer, 1989b). It is estimated that 50% of the individuals with dementia (McLean, 1987), and 10% to 20% of individuals residing in acute or long-term care facilities (Blazer, 1989a) have depressive symptoms. Additionally, depression is more prevalent with physical illness and various medications commonly used by the elderly (eg, antihypertensives and sedatives-hypnotics) (Winstead, 1984).

Despite the personal, social, and economic consequences of cognitive impairment, more than half of these persons are not identified as suffering from cognitive impairment (Lucas, 1980; Palmateer, 1985). The antiquated yet negative and fatalistic stereotype that as one becomes older one will experience a diminished capacity for clear thinking is one obstacle to identifying and treating these conditions. However, the nonspecific clinical features, often atypical and variable presentations, and frequent coexistence of these conditions also serve as obstacles to the prompt and accurate identification and diagnosis of these conditions. This article will attempt to help nurses overcome these obstacles and enable the accurate and timely identification of acute confusion, dementia, or depression in older individuals.…

Cognitive impairment is a significant problem for the elderly. Historically, cognitive impairment and aging have been considered synonymous. Current attitudes and thoughts of aging are more enlightened: cognitive impairment is no longer perceived as a "benign" and inevitable concomitant of aging but as a condition that warrants prompt and aggressive action. For this action to be efficacious, the specific nature, or type, of the cognitive impairment must be identified precisely. In other words, it must be determined accurately if the condition is an acute confusional state, dementia, or depression - a distinction that is not always readily apparent.

Acute confusion, also known as delirium, transient cognitive impairment, ICU psychosis, and several other names, is a prevalent condition occurring in as many as 80% of elderly patients hospitalized for acute physical illness (Foreman, 1990). An acute confusional state is a simultaneous disturbance in consciousness, attention, perception, memory, orientation, thinking, psychomotor behavior, and the sleep-wake cycle (Foreman, 1991). These symptoms of acute confusion develop abruptly over a period of hours and tend to fluctuate diurnally.

Acute confusion is associated with increased morbidity (Weddington, 1982), increased intensity of nursing care (Williams, 1986), longer hospitalization (Lipowski, 1983; Weddington, 1982), increased rates of nursing home placement on hospital discharge (Levkoff, 1986; Lipowski, 1983), and increased mortality (Weddington, 1982). All of these factors contribute to the increased per day hospital costs associated with providing care to acute confused older patients. Levkoff and colleagues (1986) estimated that reducing the length of hospitalization by just I day would save Medicare $1 to $2 billion annually.

Dementia is a chronic, insidious, progressive, and permanent form of cognitive impairment. It is an impairment of higher cortical functions, including memory, that is manifested by difficulties in day-to-day functioning, problem solving, and in the control of emotions (Bondareff, 1986). Currently, dementia is estimated to affect 1 to 5 million Americans (Office of Technology Assessment, 1987). It is projected that by the year 2040, dementia will affect 7.4 million Americans (Office of Technology Assessment, 1987). Although dementia has no known cure, in many instances the cognitive decline associated with dementia can be slowed or even halted.

Depression is frequently referred to as pseudodementia and pseudodelirium because of the similarities in the clinical features among delirium, depression, and dementia (Blazer, 1989a). As a mood disturbance consisting of dysphoria, feelings of sadness, pessimism, hopelessness, and loss of interest or pleasure in most activities (American Psychiatric Association, 1987; Staab, 1990), depression is the most frequent psychiatric disorder of old age (Kane, 1984). Of community-residing elders, 2% to 14% have major depression, whereas approximately 15% have mild depression (Blazer, 1989b). It is estimated that 50% of the individuals with dementia (McLean, 1987), and 10% to 20% of individuals residing in acute or long-term care facilities (Blazer, 1989a) have depressive symptoms. Additionally, depression is more prevalent with physical illness and various medications commonly used by the elderly (eg, antihypertensives and sedatives-hypnotics) (Winstead, 1984).

Despite the personal, social, and economic consequences of cognitive impairment, more than half of these persons are not identified as suffering from cognitive impairment (Lucas, 1980; Palmateer, 1985). The antiquated yet negative and fatalistic stereotype that as one becomes older one will experience a diminished capacity for clear thinking is one obstacle to identifying and treating these conditions. However, the nonspecific clinical features, often atypical and variable presentations, and frequent coexistence of these conditions also serve as obstacles to the prompt and accurate identification and diagnosis of these conditions. This article will attempt to help nurses overcome these obstacles and enable the accurate and timely identification of acute confusion, dementia, or depression in older individuals. The clinical features of these three conditions are compared and contrasted, and recommendations for their detection and identification are offered.

CLINICAL FEATURES

A comparison of the clinical features of acute confusion, dementia, and depression can be found in the Table. A discussion of the major features is given in greater detail below.

Onset

The onset of cognitive impairment should, by definition, differ among the three types and, therefore, facilitate differentiation. By definition, an acute confusional state has an abrupt and overt onset that can be timed and dated. Dementia, on the other hand, has a protracted and insidious onset that typically is difficult to date. It generally takes months or years before close friends or relatives recognize changes in the individual's ability to think and function. Although depression also has a relatively abrupt onset, it is often difficult to date as a result of the somatization of the depressive symptoms (eg, lack of appetite, apathy, and listlessness), which are often overlooked as physical illness. Also, because many of the cognitive features are similar to those of dementia, many elders who think they are in the early stages of dementia are reluctant to bring attention to these symptoms. Thus, evaluation and treatment of these symptoms are delayed. Classically, however, the onset of depression coincides with a specific factor, which facilitates the dating of the onset.

The inherent difficulty with using onset as a means to differentiate among these three conditions is that onset can only be known retrospectively and is strongly influenced by the nature of the etiologic agents. For example, if the etiologic agent is of sufficient acuity and severity (eg, profound and prolonged hypoxia), the onset will be abrupt but the condition will be dementia, not acute confusion. Similarly, with the continuous but negligible loss of serum electrolytes (eg, sodium and potassium) associated with long-term diuretic therapy, the onset will be insidious and the condition acute confusion, not dementia. Thus, although onset classically differs among these conditions, other factors have a profound influence that renders this clinical feature unreliable.

Table

TABLEA Comparison of the Clinical features of Acute Confusion, Dementia, and Depression*

TABLE

A Comparison of the Clinical features of Acute Confusion, Dementia, and Depression*

Table

TABLEA Comparison of the Clinical features of Acute Confusion, Dementia, and Depression*

TABLE

A Comparison of the Clinical features of Acute Confusion, Dementia, and Depression*

Course

The course of an acute confusional state is, by definition, short. The classic characteristic is the fluctuating nature of the symptomatology with a worsening of symptoms and behavior in the evening. Although there are diurnal variations in the symptoms and behavior of depressed individuals, the fluctuations are not as extreme as with an acute confusional state. Typically, symptoms and complaints with depression are worse in the early morning, rather than in the evening as with acute confusion. Also, there may be situational variations in the symptoms associated with depression; eg, in situations of grief. Conversely, the course of the symptomatology associated with dementia, although progressive, is relatively stable over time.

Duration

The duration of an acute confusional state is transient; ie, it is short, lasting hours to at most days. However, reversibility is a function of discovering and treating the underlying causal agents promptly and appropriately. Depression is of intermediate duration, typically lasting a few weeks to months. Yet, because it is frequently difficult to date the onset of depression, duration is confounded. Also, if untreated, depression may become chronic, lasting several years. Although there are reports of slowing or halting the progression of the cognitive decline, dementia is protracted and irreversible. Because duration can only be known retrospectively and is dependent on correctly identifying and treating the causal agents, duration, as with onset, is not a reliable discriminating clinical feature.

Attention

Attention is a relatively new, yet diagnostically useful, clinical feature of these conditions. With depression, attention remains relatively unaffected; the same is true of dementia until the late stages in which there may be attention deficits. Attention deficits are, however, one of the hallmarks of an acute confusional state. An acutely confused individual is unable to sustain or shift attention to various stimuli. Recent work by Foreman and Inouye has shown measures of attention to have the greatest diagnostic utility in differentiating among patients with dementia, depression, and acute confusion.

Orientation

Orientation has been used universally and historically to provide information about an individual's cognitive status. However, if one considers the environment in which older individuals receive health care (eg, hospitals and nursing facilities) and the effects of physical illness, it should not be surprising to find these individuals disoriented to time and place. Yet, nurses rely almost exclusively on the presence of disorientation as a means of identifying cognitive impairment. Although disorientation is necessary for an individual to be considered acutely confused, it is an insufficient indicator. Recent studies have shown disorientation to be nonspecific for identifying acutely confused elders (Foreman, 1991; Inouye, 1990). Additionally, disorientation may or may not be present in dementia and depression, and may merely reflect the condition of the environment rather than the ability of the individual.

Memory

Memory impairment is a feature common to all three conditions, but the nature of the impairment is different. With depression, the individual's complaints of memory loss far exceed the actual loss as evidenced by observations of the individual's behavior and ability to function, and by formal cognitive testing. This is a classic feature of depression. The opposite is true of dementia. Individuals with dementia attempt to conceal their memory loss by developing crutches (eg, mnemonics) or using other strategies to function while deceiving others. Demented individuals frequently resort to confabulation, "the recitation of imaginary experiences to fill in gaps in memory," (Dorland's, 1985). An acutely confused individual has problems with immediate and recent memory, and, therefore, has difficulty learning and using new information. These memory problems may be primary or secondary to attention deficits.

Thinking

Thinking is another useful clinical feature of cognition for differentiating among these three conditions. Acute confusion is associated with disorganized thought; acutely confused individuals are incoherent, illogical, undirected, and unconnected. Demented individuals have difficulty with abstract thinking, and, as a result, the content of thought is impoverished. Otherwise, individuals with dementia think in an organized and connected manner. The ability to think is not impaired in persons with depression; however, their thoughts appear slow and indecisive. The themes of thoughts of depressed individuals reflect hopelessness, helplessness, and self-devaluation.

Perception

Perceptual disturbances (eg, hallucinations and illusions) are a feature of acute confusion and are thought to be projections of personally meaningful thoughts, images, and fantasies (Berensin, 1988). Acutely confused individuals frequently mistake the unfamiliar for the familiar; eg, the nurse becomes a relative or neighbor. Demented individuals rarely have perceptual disturbances, but they may have paranoid thoughts. Depressed individuals do not have perceptual problems; however, in severe cases, perceptual misinterpretations may reflect underlying thoughts of hopelessness, helplessness, or self-deprecation.

Psychomotor Behavior

The psychomotor behavior associated with each of these three conditions is highly variable. Lipowski (1983) described three variants of psychomotor behavior associated with acute confusion: hypokinetic, in which the individual is lethargic and somnolent with minimal body movement; hyperkinetic, in which the individual is agitated, restless, picks at bedclothes, and pulls at tubes; and a mixed variant, in which the individual fluctuates between the hyperkinetic and hypokinetic variants. Typically, a depressed individual has retarded psychomotor movement but not as pronounced as that seen in the hypokinetic variant of acute confusion. The psychomotor behavior of a demented individual is generally normal; however, apraxia may be present.

Sleep-Wake Cycle

Individuals who are acutely confused have reversed sleep-wake cycles, being awake at night and somnolent during the day. This reversal in the sleep-wake cycle resulted in acute confusion being referred to as a state of disordered wakefulness (Lipowski, 1983). However, it remains unclear as to whether sleep disturbances are a cause or an effect of the acute confusional state. Demented individuals, on the other hand, tend to experience fragmented sleep; that is, these individuals frequently awake but return to sleep, whereas depressed individuals classically experience early morning awakening (approximately at 4 AM) and cannot return to sleep.

MENTAL STATUS TESTING

Numerous methods are available for evaluating the cognitive ability of patients (Fraser, 1988). The most common method is the mental status questionnaire, the most familiar being Pfeiffer's (1975) Short Portable Mental Status Questionnaire, Folstein's (1975) Mini-Mental State Examination, Jacob's (1977) Cognitive Capacity Screening Examination, and Kiernan and colleagues' (1987) Neurobehavioral Cognitive Screening Examination. For each questionnaire, a score above a specified cut-off signifies that cognitive abilities remain intact; below the cut-off, cognition is impaired. Most directions for the use of mental status questionnaires encourage summing the number of errors to determine a total score. However, scores on mental status questionnaires can be misleading as the severity of the cognitive impairment, level of formal education, fatigue, and characteristics of the testing environment adversely influence performance and thus the total score. For example, patients who are depressed more frequently respond with "I don't know." Depressed individuals lack interest in mental status testing and, therefore, have difficulty completing the testing. As an expression of their lack of interest, depressed individuals will complain of fatigue, of being too ill, or offer a similar complaint to terminate the testing. Conversely, demented individuals, aware of their incorrect responses, seek validation by asking, "Is that right?" As a result, demented individuals take great effort and struggle with finding the correct or appropriate responses. Demented individuals also are known to confabulate; that is, they make up details in life events to fill in the gaps. Acutely confused individuals, on the other hand, are easily distracted by environmental stimuli, have difficulty concentrating on the task at hand, and have little awareness of making mistakes with mental status testing.

RECOMMENDATIONS

The assessment of the cognitive abilities of elderly individuals is essential to their well-being. It is recommended that cognition be assessed routinely so that any change in functioning can be detected promptly; systematically so that every assessment is performed similarly, thereby ensuring that changes reflect the patient's status and not a difference in nurses performing the assessment; and comprehensively so that all aspects of cognition are assessed, thereby providing information for determining the exact condition (Foreman, 1989). To ensure that the assessment is systematic and comprehensive, use of a mental status questionnaire and a behavioral rating scale is recommended (Blass, 1985; Foreman, 1989). It is important to remember that it is not so much which of these instruments is used but that one is used routinely.

Mental status questionnaires are composed of carefully chosen questions to provide information about the various components of cognition (ie, consciousness, attention, memory, orientation, and higher integrative functions). The questionnaires vary in length and combination of questions. Bedside screening variants of the mental status questionnaires have been adapted to provide a practical yet sensitive method to test patients. Although averaging 10 questions in length, these bedside screens are heavily verbal and require that the patient be able to see, hear, and communicate verbally. Deaf, blind, or aphasie patients, or those with poor language skills, may perform poorly even if they are cognitively intact. Furthermore, many of the patients in critical care units are intubated.

Thus, before a mental status questionnaire can be used to test the cognitive status of an intubated patient, the nurse must devise a response mode other than verbal through which the patient can answer. For example, the nurse might determine whether the patient is oriented to time by saying, "I would like you to tell me the day of the week. I will slowly say the days of the week. When I mention the name for this day, please blink your eyes," (Foreman, 1989).

Because much of the behavior associated with impaired cognition is nonverbal, use of a behavioral rating scale is recommended. This is important because behavioral rating scales provide valuable information about the patient's ability to function in the environment (Blass, 1985). A behavioral rating scale is particularly useful for differentiating among acute confusion, dementia, and depression. The scales also have proved useful for grading the severity of the problem (Vermeersch, 1990). (For an in-depth discussion of the instruments available for evaluating cognition and mental status, see Fraser, 1988.)

SUMMARY

An acute confusional state is a primary attention disorder with an acute onset and fluctuating symptomatology. Dementia is an insidious and progressive condition of a primary memory deficit. Depression is a primary mood disorder. These conditions can occur independently or can coexist, but they are associated with significant negative consequences for elderly individuals that can be ameliorated by the prompt and accurate identification of the condition.

REFERENCES

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TABLE

A Comparison of the Clinical features of Acute Confusion, Dementia, and Depression*

TABLE

A Comparison of the Clinical features of Acute Confusion, Dementia, and Depression*

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