Wrist actigraphy for measuring sleep in intervention studies with Alzheimer's disease patients: application, usefulness, and challenges

Sleep disorders are common in patients with Alzheimer's disease (AD). An important aspect of intervention studies in patients with sleep disorders is the choice of assessment strategy. This paper presents a literature review concerning assessment strategies for measuring sleep in intervention studies with AD patients, with a focus on actigraphy. Thirty-seven articles were selected for this review, having analysis of sleep/nocturnal rhythm disturbances by actigraphy as the primary or secondary outcome. The advantages and limitations of actigraphy were discussed vis-à-vis polysomnography and subjective interventions. The following methodological aspects were addressed: impact of experimental design and patient setting, inclusion and exclusion criteria, placement of the actigraphy device, adherence to the regimen, duration of recordings and the choice of sleep parameters. Our analyses suggest that the methods used in intervention studies encompassing sleep disorders and dementia could be improved by increasing accuracy of diagnosis, categorization of sleep disturbances, adherence to actigraphy, and by clearly defining the variables and endpoints in each study. Also, controlling variables that could interfere with sleep and describing the data processing and analysis might improve interpretation of results.