Actimetry-Derived 24 h Rest–Activity Rhythm Indices Applied to Predict MCTQ and PSQI

Abstract

The aim of this study was to identify wrist actimetry-based indices associated with the sleep–wake rhythm characteristics of healthy individuals. The study involved 79 healthy subjects of both sexes (age range 15–62 years (mean: 21.5 ± 9.6 years, women: 77.8%)). Each participant provided personal data, filled out two questionnaires, the Munich ChronoType Questionnaire (MCTQ) and the Pittsburgh Sleep Quality Index (PSQI), and wore a wrist actimeter for a week. A significant positive association of the chronotype with the mid-phase of the most active 10 h period (M10t: B = 0.252, p = 0.015), the mid-phase of the least active 5 h period (L5t: B = 0.338, p = 0.005), and the interdaily stability (IS: B = −0.021, p = 0.017) was noted, as well as the sleep duration with the M10t (B = −0.257, p = 0.003), L5t (B = −0.340, p = 0.001), and IS (B = 0.042, p = 0.003). There was a significant association of social jetlag (B = 0.320, p = 0.032) and sleep quality (B = 0.990, p = 0.013) with motor activity in bed, as well as sleep efficiency with the acrophase (B = −0.043, p = 0.007). Nonparametric indices of the 24 h rest–activity rhythm are useful tools for assessing the sleep–wake rhythm of healthy individuals.