A new light source (Valkee©) does not alter sleep–wake parameters and does not improve mood in phase delayed subjects

• Published in: Sleep and biological rhythms Vol. 14; no. 1; pp. 97 - 105
• Main Authors: Pallesen, Ståle, Nødtvedt, Øystein, Saxvig, Ingvild West, Bjorvatn, Bjørn
• Format: Journal Article
• Language: English
• Published: Tokyo Springer Japan 01.01.2016
• Subjects: Biomedical and Life Sciences; Biomedicine; Health Psychology; Human Physiology; Internal Medicine; Neurology; Neurosciences; Original Article; Psychiatry; Transcranial bright light; Mood; Sleep–wake rhythm; Randomized controlled trial
• ISSN: 1446-9235; 1479-8425
• DOI: 10.1007/s41105-015-0027-5

Not much evidence exists concerning the effects on sleep and mood of transcranial bright light. In this study, 50 students, all with wake-up time 9:00 a.m. or later in weekends/free days, participated in a double-blind placebo-controlled experiment comparing the effects of bright light ( n  = 27; 8.0 lm) and placebo ( n  = 23; 0.1 lm). Data collection consisted of sleep assessment, with both sleep diaries and actigraphy. In addition, the Fatigue Severity Scale and the Profile of Mood States (POMS) were administered. Following 1 week of baseline recording, the therapy was initiated, aiming to phase advance the sleep–wake period. The therapy lasted for 2 weeks and consisted of gradually advancing daily light exposure of 12 min’ transcranial bright light. Subjects in the two conditions did not change differently from baseline to post-treatment on any sleep parameters. A significant condition × time interaction was found for one of six subscales (vigor–activity) of the POMS, suggesting a more favorable development from baseline to post-treatment in the placebo compared to the bright light condition. No differences in terms of side-effects were reported between conditions. It is concluded that transcranial bright light, at times where conventional light therapy has phase-advancing properties, did not influence any sleep parameters differently than placebo. Transcranial bright light was associated with a less favorable development from baseline to post-treatment on one mood parameter compared to placebo.