Actigraphic sleep tracking and wearables: Historical context, scientific applications and guidelines, limitations, and considerations for commercial sleep devices

Objective estimation of sleep can utilize a range of technologies. For field-based recordings, the most accepted approach is “actigraphy,” or movement-based estimation of sleep versus wake. Actigraphy is based on technology developed over several decades and has been repeatedly validated against in-lab polysomnography. This chapter reviews the history and technology behind actigraphy, addresses the issues around validation, and describes the chronology of this tool as a way to characterize habitual sleep. In addition, this chapter addresses newer implementations of this technology, including the use of consumer-grade wearables and integration with other approaches to improve measurement (e.g., optical plethysmography). Finally, the chapter provides recommendations for implementation of an actigraphy program and guidelines for understanding actigraphy validation.