Methodological challenges when using actigraphy in research.

Actigraphy has become a valuable clinical and research tool to objectively evaluate sleep, daytime activity, and circadian activity rhythms in healthy individuals as well as persons with primary and comorbid insomnia. However, procedures used for sampling, data processing, and analysis are not consistently reported in the literature. The wide variability in how actigraphy is reported makes it difficult to compare findings across studies. The procedures and reporting methods from 21 studies that used actigraphs to assess sleep and wake in adult patients with cancer are reviewed to highlight the differences in reporting strategies. Patients with cancer were chosen to illustrate the methodological challenges related to procedures and reporting in one population. The aim of this article was to advance standards of information presented in publications to enable comparisons across research studies that use actigraphy. Specific methodological challenges when using actigraphy in research include instrumentation, selection of pertinent variables, sampling, and data processing and analysis. Procedural decisions are outlined and discussed, and suggestions are made for standardized actigraphy information to include in research reports. More consistent procedures and reporting will advance the science of sleep, daytime activity, and circadian activity rhythms and their association with other health-related variables.