Clinical Review

Cognitive Screening Tools

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As the US population ages, the need grows for clinicians in all settings to be familiar with currently available cognitive screening tools. These tools, though not diagnostic, are useful in the early recognition of cognitive changes and of possible underlying dementia. No single cognitive screening tool is appropriate for use in all settings or with all populations. The components, scoring, and interpretation of the more commonly used cognitive screening tools are described here, with their respective benefits and limitations.


 

As our elderly population continues to grow, the issues of screening for cognitive impairment and early detection of dementia are becoming increasingly important. Cognitive impairment, particularly in individuals who live alone, contributes to loss of independence, decreased quality of life, and increased health care costs.1 There are serious and costly implications of unrecognized dementia, including delayed treatment of reversible conditions, medication noncompliance for comorbid conditions, inaccurate and unreliable reporting by patients, safety concerns, potential catastrophes, and increased risk for victimization.
Clinicians in all settings can expect to care for increasing numbers of older adults—many with various degrees of cognitive difficulties. Such problems, especially if undetected, can significantly impact the ongoing management of both acute and chronic medical problems. In primary care settings, it has been reported, between 50% and 65% of patients found to have cognitive deficits meeting the criteria for dementia did not have a diagnosis of dementia noted in their medical record.2
The annual wellness examination provided for under the Patient Protection and Affordable Care Act3 (PPACA) for Medicare beneficiaries is required to include an assessment of cognitive function,4 but the Centers for Medicare and Medicaid (CMS) have not, to date, recommended any specific screening instrument; examiners are expected to base their assessment on observation and reports from the patient and other informants.5
WHY DO TESTING?
The purpose of cognitive screening tests is to aid the clinician in early detection of cognitive change as a first step toward accurate diagnosis—a process that requires further assessment. Such changes may herald the beginning of a dementia, such as Alzheimer’s disease, or may indicate an increased risk for delirium, such as in the postoperative setting,6 or functional decline with accompanying safety concerns.7 Early identification of cognitive changes provides an opportunity for case finding, crisis avoidance, and identification of patients for earlier intervention and management, including a discussion of goals with the patient, and assurance that advance directives are complete and accurate.
It is well documented that dementia remains underrecognized and may indeed be the “silent epidemic” of this century.8 Current estimates are that the incidence of new cases of Alzheimer’s disease will double by 2050.9 Additionally, improvement in stroke survival rates means that there will likely be increases in vascular and poststroke dementia, as one-third of stroke patients have been found to develop a progressive dementia.10
The early detection of cognitive change offers benefits for both patients and providers. If early detection leads to a diagnosis of dementia (regardless of etiology), this can provide an explanation to patients and families regarding recent changes in function, mood, and behavior. A diagnosis of progressive dementia (eg, Alzheimer’s disease, Lewy body disease, frontotemporal dementia) provides an opportunity for early medication management, review and simplification of ongoing chronic disease management, and prevention of problems commonly associated with mismanagement. More importantly, early diagnosis of dementia enables patients to be more involved in planning for their own future care needs, such as execution of advance directives.
Cognitive screening may also help in identification of the at-risk driver or those who should undergo further assessment for fitness to drive.7
WHO SHOULD BE SCREENED?
There is no clear consensus on who should undergo cognitive screening or how frequently it should be carried out. Screening should be targeted at individuals who are at greatest risk for either progressive dementia or delirium. Advancing age is a known risk factor for dementia, but there is no agreement on a specific age at which to initiate cognitive screening. In patients older than 80, there is a 25% to 50% prevalence of dementia,1,11,12 thus suggesting that cognitive screening should be initiated before this age. Furthermore, clinicians who provide medical care for patients of advanced age must be increasingly attentive to the possible presence of cognitive decline.
Individuals with subjective memory complaints and those with a history of depression have been identified as being at high risk for dementia.13,14 The American Academy of Neurology recommends cognitive screening in any patient in whom cognitive impairment is suspected.15 This usually occurs when a family member or other individual close to the patient (eg, employer, friend) becomes concerned about changes in the patient’s thinking, behavior, or function. Additionally, older individuals who have recently undergone surgery or been hospitalized are a population at high risk for acute cognitive changes and should be considered candidates for mental status screening.16-20

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