Practice Imperfect: Repeated Cognitive Testing Can Obscure Early Signs of Dementia (UC San Diego Health press release):
“Alzheimer’s disease (AD) is a progressive, neurodegenerative condition that often begins with mild cognitive impairment or MCI, making early and repeated assessments of cognitive change crucial to diagnosis and treatment.
But in a paper published online in the journal Alzheimer’s & Dementia: Diagnosis, Assessment & Disease Monitoring, a team of researchers led by scientists at the University of California San Diego School of Medicine found that repeated testing of middle-age men produced a “practice effect” which obscured true cognitive decline and delayed detection of MCI.
“When persons take the same or similar tests repeatedly over time, they simply get better at taking the tests,” said first author Jeremy A. Elman, PhD, a postdoctoral fellow in the lab of senior author William S. Kremen, PhD, professor of psychiatry and co-director with Carol E. Franz, PhD, of the Center for Behavior Genetics of Aging at UC San Diego School of Medicine. “The consequence is that their results may not accurately reflect the reality of their condition.”
Underdiagnosis of mild cognitive impairment: A consequence of ignoring practice effects (Alzheimer’s & Dementia: Diagnostic Assessment & Prognosis). From the abstract:
- Introduction: Longitudinal testing is necessary to accurately measure cognitive change. However, repeated testing is susceptible to practice effects, which may obscure true cognitive decline and delay detection of mild cognitive impairment (MCI).
- Methods: We retested 995 late-middle-aged men in a ?6‑year follow-up of the Vietnam Era Twin Study of Aging. In addition, 170 age-matched replacements were tested for the first time at study wave 2. Group differences were used to calculate practice effects after controlling for attrition effects. MCI diagnoses were generated from practice-adjusted scores.
- Results: There were significant practice effects on most cognitive domains. Conversion to MCI doubled after correcting for practice effects, from 4.5% to 9%…
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