The effects of bright light treatment via ear canals on quality of sleep and depressive mood among overworked employees: A randomized-controlled clinical trial
Affiliations: [a] Department of Basic Nursing and Health Science, Ehime University Graduate School of Medicine, Toon, Ehime, Japan
| [b] Department of Public Health, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan
| [c] Special Course of Food and Health Science, Department of Bioscience Graduate School of Agriculture, Ehime University, Matsuyama, Ehime, Japan
| [d]
Human Factors Research Institute, Japan Foundation for Environmental Health Sciences, Minato-ku, Tokyo, Japan
Correspondence:
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Address for correspondence: Tetsu Kinoshita, Department of Basic Nursing and Health Science, Ehime University Graduate School of Medicine, Shitsukawa, Toon-city, Ehime, 791-0295, Japan. Tel.: +81 89 960 5437; E-mail: tetsu.prospective@gmail.com.
Abstract: BACKGROUND:Many overworked employees need tools to improve their depressive mood or sleep disorder. In Finland, a new device of bright light therapy was developed. OBJECTIVE:Our objective was to evaluate the effect of bright light treatment via ear canals on improving the depressive mood and sleep disorder. METHODS:We conducted a randomized, controlled, crossover designed, open-label trial. We examined 27 participants aged 23–52 years, assigned to either Early treatment or Later treatment groups. The Early treatment group used the device on weekdays for the first 4 weeks, followed by a 4-week observation period. The Later treatment group had an observation period for the first 4 weeks, followed by device treatment for the subsequent 4 weeks. Every Friday, the participants were asked to answer questionnaires: A Self-rating Depression Scale (SDS), an Athens Insomnia Scale (AIS), and a Profile of Mood States (POMS) Brief Form. RESULTS:While no significant effect was found on the SDS following treatment (p = 0.16), the AIS showed a significant improvement (p = 0.004), and the scores for the Depression (D) and Vigor (V) of POMs decreased significantly (p = 0.045, p = 0.006, respectively). CONCLUSIONS:Bright light treatment via ear canals may improve sleep quality and depressive mood.
