Association between the Munich Chronotype Questionnaire and Wrist Actigraphy

Chronotype refers to individuals’ preferences for timing of sleep and wakefulness. It can be quantifed by measuring the midpoint time between the start and end of sleep during free days. Measuring chronotype is helpful to diagnose circadian rhythm sleep-wake disorders. Te Munich Chronotype Questionnaire (MCTQ) is a self-reported measure of chronotype that calculates the midpoint of sleep on free days based on self-reported bed and wake times. Self-reports of sleep are prone to bias. Te objective was to examine the agreement between the MCTQ-derived midpoint and an objective measure obtained using wrist actigraphy. Te sleep of 115 participants aged 18–34 (mean = 24, SD = 4.6) was monitored with actigraphy for 4 to 6 consecutive nights. Te corrected midpoint of sleep on free days was derived from sleep start and end times on both free days and scheduled days. Te corrected midpoint of sleep on free days as measured by the MCTQ was 4:56 (SD = 1 : 16) and by actigraphy was 4:51 (SD = 1 : 23).Tey were not signifcantly diferent (p(87) = 0.66, p = 0.51). A strong correlation was found between these two measurements (p (88) = 0.73, p < 0.001).Te 95% limits of agreement were between −1:37:19 and 2:14:38. MCTQ and actigraphy provide similar results for the corrected midpoint of sleep on free days.