Steady as she goes! Daily fluctuations in cognitive ability are associated with risk of Alzheimer’s disease

Alzheimer’s disease (AD) is a neurodegenerative disorder that results in progressive loss of cognitive function. It is critical to identify individuals who are at the highest risk of developing AD as early as possible so that appropriate treatment plans can be developed. Neuropsychological tests of psychomotor speed, attention, and memory are frequently used to assess AD risk, and these cognitive functions are usually measured in a single session at regular but wide intervals (e.g., once per year). This assessment paradigm provides only a snapshot of cognitive performance and ignores fluctuationsin performance that may occur from day to day. A large literature indicates that daily variations in cognition are associated with numerous factors, including fatigue, stress, and motivation. In a study recently published in Neuropsychology, Andrew J. Aschenbrenner, Jason Hassenstab, John C. Morris, Carlos Cruchaga, and Joshua J. Jackson investigated whether variability in cognitive performance across distinct testing occasions is associated with risk of AD, defined as possessing a genetic risk factor, the apolipoprotein E (APOE) ε4 allele.