A modified at-home methodology for measuring dim light melatonin onset timing in healthy adults

The goal of this study was to investigate whether a modified at-home dim light melatonin onset (DLMO) assessment would be comparable to the in-laboratory DLMO assessment. Fifty-five participants underwent the at-home DLMO, while 55 age- and sex-matched participants underwent the in-laboratory DLMO assessment. Each participant underwent 14 d of actigraphy monitoring with sleep diary, one overnight polysomnography (PSG), followed by another night for DLMO assessment, either in the laboratory or at home. The at-home DLMO and the in-laboratory DLMO were correlated to chronotype and habitual sleep wake time. DLMOs, compliance with the sampling time and dim lighting were compared between the two groups. The DLMOs were similar between at-home and in-laboratory assessments (Absolute threshold: 22:14 h at home and 22:30 h at in-laboratory, p = 0.18; Relative threshold: 21:42 h at home and 22:19 h at in-laboratory, p = 0.17). The earlier at-home DLMO and earlier in-laboratory DLMO were both moderately correlated to earlier chronotype and earlier sleep wake time. The compliance with the scheduled sampling time was slightly lower than that in the laboratory, while the compliance with dim lighting was comparable between the at-home group and the in-laboratory group. Our modified at-home assessment of DLMO is a feasible and valid alternative to the in-laboratory assessment.