Pieter Heeren, Johan Flamaing, Jos Tournoy, Marquis D. Foreman, and Koen Milisen
EDUCATIONAL OBJECTIVES
On completion of this chapter, the reader should be able to:
1. Discuss the importance of assessing cognitive function
2. Describe the methods of assessing cognitive function
3. Compare and contrast the clinical features of delirium, mild cognitive impairment, dementia, and depression
4. Incorporate the assessment of cognitive function into daily practice
OVERVIEW
Cognitive function comprises perception, memory, and thinking—the processes by which a person perceives, recognizes, registers, stores, and uses information (Foreman & Vermeersch, 2004). Although alterations in cognitive functioning are inherent to aging, there are criteria that define pathological conditions, such as delirium, mild cognitive impairment, dementia, and depression (American Psychiatric Association, 2013). These disorders have diverse clinical features and causes, but are all characterized by decline from a previously attained level (Sachdev et al., 2014). Clinicians often fail to detect these disorders in older adults, when only using routine history and standard examination (Burton et al., 2012; Douzenis et al., 2010; Torisson, Minthon, Stavenow, & Londos, 2012). This might have serious consequences that include missed opportunities to treat correctable conditions and minimize or prevent unfavorable outcomes such as functional decline and death (Bradshaw et al., 2013; Torisson et al., 2012). Assessing cognitive functioning is paramount for the early detection of pathological conditions and for monitoring the effectiveness of interventions (McCarten et al., 2012).
BACKGROUND AND STATEMENT OF PROBLEM
Declines in cognitive function are a hallmark of aging (McEvoy, 2001); however, most declines in cognition with aging have no or minor clinical impact and are not pathological. Examples of nonpathological changes include a diminished ability to learn complex information, a delayed response time, and minor loss of recent memory; declines are especially evident with complex tasks or with those requiring multiple steps for completion (McEvoy, 2001).
Pathological conditions of cognitive impairment that are prevalent with aging include delirium, mild cognitive impairment, dementia, and depression (depression can also be present without cognitive impairment; please see Table 6.1 for a comparison of the clinical features. Chapters 15, 16, and 17 describe these conditions more extensively. Several strategies exist to prevent, treat, or slow these conditions (Inouye, Westendorp, & Saczynski, 2014; Langa & Levine, 2014). However, these opportunities exist mainly when and if these conditions are detected early.
TABLE 6.1
A Comparison of the Clinical Features of Delirium, Mild Cognitive Impairment, Dementia, and Depression
Clinicians often fail to evaluate cognitive function when using routine history and standard examination (Burton et al., 2012; Torisson et al., 2012). Hence, early detection of cognitive impairment exists only when cognitive function is assessed (McCarten et al., 2012). Without assessment, these pathological conditions are often un(der)diagnosed (Torisson et al., 2012), and the individuals with these conditions face much greater, accelerated, and long-term cognitive and functional decline and death (Barry, Murphy, & Gill, 2011; Bradshaw et al., 2013). Yet, it is clear that the assessment of cognitive function is a crucial step in a cascade of strategies to prevent, reverse, halt, or minimize cognitive decline.
ASSESSMENT OF THE PROBLEM
Methods for Assessing Cognitive Function
A two-step approach is recommended for determining the nature of impairment (Cordell et al., 2013; Jackson, Naqvi, & Sheehan, 2013; Simmons, Hartmann, & Dejoseph, 2011). The first step is screening for impairment, the second includes a full evaluation, if necessary. Screening is conducted to briefly determine the presence or absence of impairment. If screening results indicate possible impairment, a full evaluation is necessary to make a diagnosis of dementia, delirium, depression, mild cognitive impairment, or some other health problem. The content of a full evaluation varies depending on the patient’s presentation and includes tests to find out the etiologies of impairment and assess its severity (Cordell et al., 2013).
When a diagnosis is made, appropriate reassessment or monitoring is necessary to track cognitive and global functioning over time as a means for following the progression or regression of impairment, especially in response to treatment (Cordell et al., 2013; Shenkin, Russ, Ryan, & MacLullich, 2014).
Instruments to Screen for Cognitive Impairment
Numerous instruments are available to assess cognitive functioning, of which Folstein’s Mini-Mental State Examination (MMSE) is the most frequently recommended and best studied (Folstein, Folstein, & McHugh, 1975; Lin, O’Connor, Rossom, Perdue, & Eckstrom, 2013; Tombaugh & McIntyre, 1992). The MMSE consists of 11 items assessing orientation, attention, memory, concentration, language, and constructional ability. Each question is scored as either correct or incorrect; the total score ranges from 0 to 30 and reflects the number of correct responses. A score less than 24 is often considered demonstrative of impaired cognition.
The performance on the MMSE can be influenced by education (individuals with less than an eighth-grade education commit more errors), language (non-native English speakers commit more errors, which is related to sociocultural differences), verbal ability (the MMSE can only be used with individuals who can respond verbally to questioning), and age (older people do less well; Tombaugh & McIntyre, 1992). Furthermore, it is important to stress that the MMSE is not available for public use without cost (Lin et al., 2013).
The Montreal Cognitive Assessment (MoCA) is a new instrument for detecting and monitoring cognitive impairment (Nasreddine et al., 2005). It assesses the following cognitive domains: attention and concentration, executive functions, memory, language, visuoconstructional skills, conceptual thinking, calculations, and orientation. The total score is 30 points and a score of 26 or above is generally considered normal. Validation studies of the MoCA indicate its performance to be equivalent or superior to that of the MMSE, especially in patients with mild cognitive impairment (Dong et al., 2012; Liew, Feng, Gao, Ng, & Yap, 2015). Permission to use or reproduce the MoCA is required in research and commercial settings.
As the administration times of both the MMSE and the MoCA are quite long (approximately 10−15 minutes for trained users), it is recommended to use a briefer test for screening purposes, such as the Mini-Cog (Borson, Scanlan, Brush, Vitaliano, & Dokmak, 2000), to decide whether it is appropriate to conduct the MMSE or the MoCA. The Mini-Cog is a four-item screening test consisting of a three-item recall and a clock-drawing item; for example, draw the face of a clock, number the clock face, and place the hands on the clock face to indicate a specific time such as 11:10. Although the Mini-Cog is widely used and well known, clinicians might select other brief tools to use in their clinical practice, because there is no optimal tool to detect cognitive impairment in all settings and patient populations (Cordell et al., 2013; Lin et al., 2013).
Most cognitive screenings tests, among the ones mentioned earlier, are initially developed as a measure for global cognitive abilities. Because it is often difficult to make a differential diagnosis (Is the impairment delirium, mild cognitive impairment, dementia or depression, or possibly one superimposed on another?), parallel use of other short instruments, such as the Confusion Assessment Method (CAM; Inouye et al., 1990), the Delirium Observation Screening Scale (DOSS; Detroyer et al., 2014; Schuurmans, Shortridge-Baggett, & Duursma, 2003), or the Geriatric Depression Scale (GDS; Yesavage et al., 1982), can be useful to determine the nature of impairment. See Chapters 15, 16, and 17 for a more detailed discussion about which screening tool to choose per condition.
The 4AT is a recently designed screening instrument for detecting both delirium and (moderate to severe) cognitive impairment (Bellelli et al., 2014). Its key features are: brevity (administered in less than 2 minutes), no special training required, allows for assessment of “untestable” patients, does not require supplemental materials, and incorporates brief cognitive test items. The attention item, in which a patient is asked to tell the months of the year in backward order starting from December, was reported to be very predictive for the presence of delirium (inattention was present in persons who were unable to reach July; O’Regan et al., 2014). The 4AT is free to download and use (www.the4AT.com). Although the first results concerning the 4AT are promising, more research is needed to confirm its validity and reliability (Bellelli et al., 2014; Lees et al., 2013).
It is also recommended that formal cognitive testing be supplemented with information from close relatives (Cordell et al., 2013; Langa & Levine, 2014). This information assists in determining the duration of impairment—which is crucial for making a diagnosis—and can be obtained through history taking or the Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE; Jorm & Jacomb, 1989) and/or the Family Confusion Assessment Method (FAM-CAM; Steis et al., 2012). The Neuropsychiatric Inventory (NPI; Kaufer et al., 2000) and caregiver burden assessments (Adelman, Tmanova, Delgado, Dion, & Lachs, 2014) can also be used to obtain information from relatives.
Formal screening is not always possible. When a patient is too sick for formal testing (e.g., inattentive or responding unusually or inappropriately to conversation or questioning), naturally occurring observations during daily and routine contacts with the patient (e.g., during bathing, feeding, transferring the patient) can be used to evaluate an individual’s cognitive functioning easily and in a nonthreatening way. The Nurses’ Observation Scale for Cognitive Abilities (NOSCA) was developed and validated to standardize the reporting of these observations (Persoon, Banningh, van de Vrie, Rikkert, & van Achterberg, 2011; Persoon et al., 2012).
When time is scarce, at minimum, it is necessary to establish whether a patient fulfills the criteria for delirium (Inouye et al., 1990), because patients with delirium have the highest risk for severe short-term adverse outcomes (Witlox et al., 2010). Therefore, in expectation of formal screening results, the use of the instruments mentioned earlier should temporarily be substituted by assessment of orientation (to time and place) and attention (e.g., naming of days of the week (no errors should be allowed), or months of the year backward (one error should be allowed), serial sevens (i.e., in subsequently substracting 7 from 100; one error should be allowed for five subtractions), or digit spans backward (i.e., the length of the longest list of digits that a person can recite backward; normally three or more; Inouye et al., 2014). Any suspected or uncertain cases should be handled as delirious until proven otherwise (Inouye et al., 2014).
When screening results indicate impairment, referral to a specialist setting (e.g., memory clinic, neuropsychologist, psychiatrist, advanced practice nurse, etc.) is necessary for more diagnostic workup (i.e., extensive history taking, clinical and neurological examination, extended neuropsychological assessment, brain imaging, blood sampling, etc.). Chapters 15, 16, and 17 describe more extensively how a differential diagnosis can be made.
When to Assess Cognitive Function
As there is insufficient evidence supporting universal screening for cognitive impairment in older patients (Moyer, 2014), screening interventions are usually applied to a smaller group of persons with specific risk factors (i.e., case finding). Recommendations for assessing cognition with standardized and validated tools include: presence of signs, symptoms, or complaints of cognitive impairment (Lin et al., 2013; Moyer, 2014) with behavior that is inappropriate to a situation or unusual for the individual (including functional decline; Foreman & Vermeersch, 2004); when there is no informant to confirm absence of signs or symptoms (Cordell et al., 2013); and before making important treatment decisions as an adjunct to determining an individual’s capacity to consent and capacity to adhere to treatment guidelines (Fletcher, 2007).
When and how frequently cognitive functioning needs to be (re-) assessed is in part a function of the purpose for the assessment, the condition of the patient (e.g., unusual/inappropriate behavior), and the results of prior or current testing. Of course, patients with (suspected) delirium need to be monitored frequently (e.g., every 4–8 hours) because of the possible course and risks of this condition. In case of reassessment after onset of treatment, it is important to know that delirium interventions might only need a few hours before effects can be measured, whereas effects of interventions to improve complaints and signs related to depression or dementia might only be measured after 2 or more weeks, if possible.
Cautions for Assessing Cognitive Function
Various characteristics of the physical environment should be considered to ensure that the results of the cognitive assessment accurately reflect the individual’s abilities and not extraneous factors. Overall, the ideal assessment environment should maximize the comfort and privacy of both the assessor and the individual. The environment should enhance performance by maximizing the individual’s ability to participate in the assessment process (Dellasega, 1998). To accomplish this, the room should be well lit and of comfortable ambient temperature. Lighting must be balanced to be sufficient for the individual to see the examination materials adequately, while not being so bright as to create glare. Also, the environment should be free from distractions that can result from extraneous noise, scattered assessment materials, or brightly colored and/or patterned clothing and flashy jewelry on the assessor (Lezak, Howieson, & Loring, 2004).
It will be vital to prepare the individual for the assessment—explaining what will take place and how long it will take—hence reducing anxiety and creating an emotionally nonthreatening environment and a safe individual−assessor relationship (Engberg & McDowell, 2000). Therefore, it is essential to avoid counterproductive statements that describe the assessment as consisting of “simple,” “silly,” or “stupid” questions. These tend to diminish motivation to perform and heighten anxiety when errors are committed.
Performing the assessment in the presence of others should be avoided when possible, as the other individual may be distracting. If the other is a relative, additional problems may arise. For example, when the individual fails to respond or responds in error, significant others tend to provide the answer, or to say such things as “Now, you know the answer to that,” or “Now, you know that’s wrong.” Because older adults are especially sensitive to any insinuation that they may have some “memory problem,” it is important for the assessor in these cases to stress the importance of the assessment without increasing the individual’s anxiety. An informant questionnaire, like the Informant Questionnaire on Cognitive Decline in the Elderly (like the IQCODE; Jorm & Jacomb, 1989), can be a creative solution to deal with disturbing others.
The assessment can be perceived by the individual as intrusive, intimidating, fatiguing, and offensive; characteristics that can seriously and negatively affect performance. Consequently, an initial period to establish rapport with the individual is recommended (Lezak et al., 2004). This period also allows a determination of the individual’s capacity for assessment, for example, do conditions exist that could alter the performance of the individual or interpretation of results such as sensory decrements? As a consequence, the assessor can alter the testing environment through simple methods, for example, by taking a position across from the individual or a little to the side. In this position, the individual can readily use the assessor’s nonverbal communication as well as read the assessor’s lips. Positioning also is important relative to lighting and glare.
Finally, avoid assessment periods immediately on awakening from sleep (wait at least 30 minutes) and immediately before and after meals or medical procedures (Foreman, Fletcher, Mion, & Trygslad, 2003). In addition, it should be said that even in perfect circumstances and in the absence of pathological conditions, patients may perform poorly on cognitive screening tests for other reasons, including acute illness, sleep deprivation, cultural issues, and so on (Shenkin et al., 2014) Therefore, it is paramount that screening results are reported with the appropriate context in which these were obtained. Otherwise, at a future date, patient charts might falsely reflect chronic impairment (Cordell et al., 2013; Shenkin et al., 2014).
CASE STUDY
Before
Mrs. O, a 72-year-old retired farmer’s wife, was referred to the emergency department (ED), because her primary care provider (PCP) judged her to be slow in responding. For more than 10 weeks, she has been complaining about intolerable pain in her right hip, which could not be managed effectively by the PCP with acetaminophen and tramadol hydrochloride. An x-ray had revealed that the 15-year-old hip prosthesis needed replacement and surgery had been scheduled in the upcoming week. As a result of to this problem, Mrs. O became dependent on her husband for several activities of daily living (bathing, dressing, toileting, and transferring).
In the ED
The triage nurse in the ED reports to his colleague on the observational ward that Mrs. O is a gentle, cooperative lady who needs upgrading of pain therapy in attendance of surgery. As intolerable pain is her main complaint, he administered an intravenous bolus of 5 mg piritramide.
The admitting nurse of the observational unit decides to assess Mrs. O’s cognitive functioning, because her husband reports to be overwhelmed by his wife’s condition. He described that his wife’s cognitive status was known to be problematic—she was diagnosed with mild cognitive impairment a year ago (MMSE: 22/30), but it worsened dramatically since the funeral of her sister 2 weeks ago. He also added that she had been talking nonsense from time to time since then. In brief, there are arguments for the presence of delirium, depression, and dementia, or possibly one superimposed on another.
Some instances later, Mrs. O starts shouting for help. She is agitated, disoriented to time and place, and fails to recite the months of the year backward. Blood test results show that she was experiencing multiple problems: low sodium levels, high creatinine level, and presence of inflammation. It is likely that the intravenous bolus of piritramide triggered or worsened delirium, as it is known that opiates should be administered with caution in people at risk of delirium (Clegg & Young, 2011)—which was probably not considered by the triage nurse, as he did not assess Mrs. O’s cognitive functioning before administering the drug. A transfer to the intensive care unit is necessary owing to tachycardia and surgery needs to be postponed until the aforementioned problems are corrected.
2 Weeks Later
When there were no more arguments for the presence of delirium (e.g., no fluctuating behavior, inattention or disorganized thinking, etc.), Mrs. O’s cognitive functioning (MMSE 21/30) and depressive symptoms (GDS: 2/30) were assessed to evaluate her capacity to adhere to rehabilitation following surgery.
Mrs. O had an uncomplicated postoperative course and regained functional independence after participating in a patient-centered rehabilitation program targeting patients with cognitive impairment.
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