Without lifting a finger: A novel approach to detecting sleep stages

Abnormal rapid eye movement (REM) sleep is often symptomatic of chronic disorders, however polysomnography, the gold standard and only validated method to measure REM sleep, is expensive and often impractical. Attempts to develop cost-effective ambulatory systems to measure REM sleep have had limited success. As elevated twitching is often observed during REM sleep in some distal muscles, the aim of this study was to assess the potential for a simple finger-mounted device to measure finger twitches, and thereby differentiate periods of REM and non-REM (NREM) sleep. It was predicted there would be more finger twitching in REM sleep than in NREM sleep, and there would be more finger twitching in late REM sleep than in early REM sleep.