Many cognitive tests can differentiate clinical Alzheimer-type dementia from normal cognition
WEDNESDAY, April 29, 2020 (HealthDay News) — Limited tools are available for identifying, diagnosing, and treating cognitive dysfunction from Alzheimer disease, according to three studies published online April 28 in the Annals of Internal Medicine.
Laura S. Hemmy, Ph.D., from the University of Minnesota in Minneapolis, and colleagues conducted a systematic review to summarize evidence on the accuracy and harms of brief cognitive tests for clinical Alzheimer-type dementia (CATD) in older adults with suspected cognitive impairment. Fifty-seven studies met the analysis criteria. The researchers found that many of the brief, single cognitive tests were highly sensitive and specific for differentiating CATD from normal cognition, including standalone tests (clock-drawing test: median sensitivity and specificity, 0.79 and 0.88) and the Mini-Mental State Examination (0.88 and 0.94, respectively). Lower accuracy was seen in distinguishing mild CATD from normal cognition and differentiating CATD from mild cognitive impairment.
Howard A. Fink, M.D., M.P.H., from the University of Minnesota in Minneapolis, and colleagues summarized the evidence on the effect of prescription drugs and supplements for CATD treatment. The researchers found that compared with placebo, cholinesterase inhibitors produced small average improvements in cognition, no difference to small improvements in function, no difference in the likelihood of at least moderate improvement in global clinical impression, and increased withdrawals due to adverse events. In a third study, Fink and colleagues found that amyloid positron emission tomography (PET), 18F-labeled fluorodeoxyglucose PET, and magnetic resonance imaging were highly sensitive for neuropathologic Alzheimer disease in older adults with dementia.
“Physicians have some tools to identify, diagnose, and treat cognitive dysfunction from Alzheimer dementia. However, the tools are blunt and have limited utility,” write the authors of an accompanying editorial.
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