Practice effects on cognitive testing and amyloid status

Abstract

AbstractBackgroundPractice effects are improvements in cognitive test scores due to repeated exposure to the same or similar test materials. Reduced practice effects have been reported in older adults with impaired cognition (e.g., Mild Cognitive Impairment, Alzheimer’s disease). However, to our knowledge, practice effects have not been examined in those who are classified as being amyloid positive or negative. Such information could be useful for screening individuals for clinical trials in these conditions.MethodOne hundred fifty‐five older adults with either intact (n = 63) or impaired (n = 92) cognition completed a brief battery of neuropsychological tests twice across one week and an amyloid positron emission tomography (PET) scan. Based on FDA approved prescribing and visual interpretation information, the amyloid PET scan was classified as positive (n = 95) or negative (n = 60). Practice effects across one week were quantified using regression‐based change scores from an independent sample.ResultOn a composite of seven neuropsychological test scores, those who were classified as amyloid positive showed significantly smaller practice effects than those classified as amyloid negative. Similar results were seen on practice effects for 6 of the 7 individuals tests, with smaller practice effects being seen in the amyloid positive participants.ConclusionPractice effects across one week were related to amyloid status in this sample of older adults. As such, these short‐term changes in scores on cognitive tests may be useful for enriching samples for future clinical trials in Alzheimer’s disease.