Comparing the Morningness-Eveningness Questionnaire and Munich ChronoType Questionnaire to the Dim Light XXXX Onset.

@entity2493 @entity1 @entity25
The dim light @entity2493 onset (DLMO) is the most reliable measure of central circadian timing in @entity1 . However, it is not always possible to measure the DLMO because sample collection has to occur in the hours before usual sleep onset, it requires staff support and considerable @entity1 effort, and it is relatively expensive. Questionnaires that ask @entity1 about the timing of their behavior, such as their sleep, may provide an easier and less expensive estimate of circadian timing. The objective of this analysis was to compare the MEQ score derived from the Morningness-Eveningness Questionnaire (MEQ) and the MSFsc derived from the Munich ChronoType Questionnaire (MCTQ) to the DLMO in the largest sample to date (N = 60). Our hypothesis was that MSFsc would correlate more highly with the DLMO than MEQ score. Our sample of 36 healthy controls and 24 @entity1 with delayed @entity25 ranged in age from 18 to 62 years. All @entity1 slept at times of their own choosing for a week before the assessment of their DLMO. The DLMO correlated significantly with both the MEQ score (r = -0.70, p < 0.001) and MSFsc (r = 0.68, p < 0.001). A linear regression using MEQ, MSFsc, and age to predict the DLMO explained 60% of the DLMO variance. The strongest predictor of the DLMO was MSFsc (beta = 0.51, p = 0.001), followed by MEQ (beta = -0.41, p = 0.004), and age (beta = 0.26, p = 0.013). The beta values for MSFsc and MEQ score were not statistically different from each other. Nonetheless, around a 4-h range in the DLMO was observed at a given MEQ score and a given MSFsc, indicating that neither questionnaire should be exclusively used to time light or exogenous @entity2493 treatment, as this could result in the mistiming of these treatments relative to the DLMO, thereby potentially worsening circadian misalignment.
