Practical Geriatric Assessment

Cognitive Domain

Cognitive Impairment

One of the most common causes for referral to geriatric clinics is cognitive impairment. Cognitive impairment is a widespread problem, affecting one out of eight Americans over the age of 70 years.^[31] However, cognitive impairment is often under-recognized; up to half of the individuals satisfying criteria have never received a diagnosis.^[32] The terminology related to cognitive impairment (classically, dementia) is currently in a state of flux. Importantly, decline in functional status is a critical component in the diagnostic pathways described below. The clinical diagnosis of dementia has been revised in the Diagnostic and Statistical Manual V, where dementia is included under the term 'major neurocognitive disorders'.^[33] Mild cognitive impairment will be included under the term minor neurocognitive disorder. The major difference between minor and major neurocognitive disorder is that the latter requires a decline in independent function.

Alzheimer's disease (AD) is the most common form of dementia. The Alzheimer's Association and the National Institute on Aging have recently convened expert international workgroups that have issued updated guidelines to diagnose AD, as well as mild cognitive impairment related to AD, and preclinical (or presymptomatic) AD.^[34] While AD was classically considered to have memory loss as its most prominent feature, current criteria emphasize a diversity of cognitive functions resulting in functional impairment. Thus, given the diversity of cognitive functions that can be impaired in neurocognitive disorders, the assessment of cognitive function should include multiple facets of cognition instead of just memory. The recognition of impairment in various cognitive functions is critical from both a diagnostic and functional standpoint.

Cognitive Screening. Many short screening exams are available. The Mini-Cog test is a brief cognitive screen that takes 3–4 min to administer, does not have education or language bias and can be performed by nonphysicians.^[35] It consists of a three-item recall and a clock-drawing task, which serves as the distracter. The three-item recall task, given its brevity, is largely a test of attention. The clock-drawing task assesses many cognitive domains including executive function and attention. Many versions of the clock-drawing task itself exist, as well as significant literature on how to score the clock.^[36,37] Figure 3 describes how to score the Mini-Cog test. Patients who fail the Mini-Cog test have a positive screen and should be further assessed.

(Enlarge Image)

Figure 3.

Cognition screening: Mini-Cog scoring.
Data taken from [35].

Cognitive Assessment. Many cognitive assessment tools have been described in the literature. A useful standardized cognitive assessment that draws from several cognitive domains is the Montreal Cognitive Assessment (MoCA).^[38] The MoCA is a 10-min cognitive assessment that assesses visuospatial and executive function, five-item delayed recall, a phonemic fluency task, orientation items, and tasks that evaluate attention, language and abstraction.^[102] The major advantage of the MoCA is its sensitivity for both mild cognitive impairment (90% sensitivity), as well as mild dementia (100% sensitivity).^[38] Disadvantages of the MoCA include language bias (although many translations are available, the tester still needs to be fluent in the patient's language), education bias (has an adjustment factor), and it cannot distinguish among the subtypes of dementia. More comprehensive neuropsychological assessment would be required for distinguishing specific cognitive domain deficits.

Please see Table 1, which presents a comparison of the Mini-Cog test, MoCA and the well-known Mini-Mental Status Examination.

Delirium

Delirium, an acute change in cognition and attention, is a common, morbid and costly syndrome for patients and healthcare systems. Delirious patients are at greater risk of readmission,^[39] institutionalization^[40] and long-term mortality.^[39–42] In geriatric outpatients, the prevalence of delirium is up to 7%.^[43] Since the diagnosis of dementia cannot be made during an episode of delirium, providers must be able to readily recognize delirium. Patients with pre-existing cognitive impairment are at greater risk for delirium. Since a disturbance of attention is the cardinal feature of delirium,^[44] screening and assessment for delirium can be incorporated into the cognitive examination using limited additional testing.

Delirium Screening. A simple screening measure for delirium would include an assessment of attention. Examples of this include naming the days of the week or months of the year backwards. These tasks are culturally and educationally unbiased. If the patient cannot name the days and months backwards, further assessment for delirium should be conducted.

Delirium Assessment. The confusion assessment method is one of the most widely-used algorithms to evaluate patients for delirium.^[45] According to the confusion assessment method, the diagnosis of delirium requires: an acute onset and fluctuating course; deficit of attention; and either disorganized thinking or a disturbance of consciousness.^[45] The confusion assessment method is a reliable, sensitive and specific algorithm for diagnosing delirium compared with expert clinician examination.^[46] It should be noted that patients with delirium may present with hyperactive, hypoactive, and mixed hyper-/hypo-active consciousness subtypes.

Table 1. Comparison of cognitive screening tools.
Characteristics of cognitive screening tools	Mini-Cog	MMSE	MoCA
Language bias		×	×
Education bias		×	×
Copyrighted for clinical use		×
Fast (under 5 min)	×
Assesses executive function	×		×
Detects mild cognitive impairment			×

The Mini-Cog test, MMSE and MoCA are all well-known cognitive screens. We recommend the Mini-Cog test for its rapidity and assessment of executive function, as well as a lack of education or language bias. We recommend the MoCA for a more thorough cognitive assessment given its excellent sensitivity for even mild cognitive impairment.
MMSE: Mini-Mental Status Examination; MoCA: Montreal Cognitive Assessment

Table 2. Some medications to avoid or use with caution in older adults based on the Beers and STOPP criteria.
Medication	Rationale
NSAIDs^†	Risks of gastrointestinal bleeding, peptic ulcer disease and renal dysfunction
Anticholinergics (e.g., first-generation antihistamines, tricyclic antidepressants and bladder antispasmodics)	Anticholinergic side effects including constipation, sedation, falls and confusion
Benzodiazepines	Sedation, confusion, falls and cognitive impairment
Tricyclic antidepressants	Anticholinergic side effects, are also proarrhythmic and may cause orthostatic hypotension
Glyburide	Risk of prolonged hypoglycemia
Metoclopramide, prochlorperazine and promethazine	May worsen parkinsonism
Antipsychotics/neuroleptics	Hypotension, worsening parkinsonism, falls and seizures, increased risk of stroke and mortality in people with dementia

The above medications are listed on both the Beers Criteria and the STOPP criteria as medications to avoid in older adults.
^†Patients may be taking NSAIDs without a prescription; and particular care should be given to inquiring about the use of these medications.
STOPP: Screening tool of older people's potentially inappropriate prescriptions.
Data taken from [61,63,64].