Monitoring sleep with a smartphone accelerometer

The present pilot study aimed to compare sleep estimation with a smartphone accelerometer to that of an actigraph accelerometer in healthy adults. Thirteen volunteers (four females; mean age 22.97 ± 3.44) simultaneously wore Actiwatch actigraphs and put the smartphone close to the pillow for at least four consecutive overnight recordings. On the whole, the agreement between the two devices was reasonably satisfactory for all sleep parameters considered (Total Sleep Time, Wake After Sleep Onset and Sleep Efficiency) but not for Sleep Onset Latency. To deeply understand the suitability of the smartphone in assessing sleep, future studies should necessarily use polysomnography.