Sleep and Phototherapy

J Clin Sleep Med. 2009 Apr 15;5(2):155-63.

Illuminating rationale and uses for light therapy.

Shirani A, St Louis EK.

Department of Neurology, University of Iowa Hospitals and Clinics, and University of Iowa Carver College of Medicine, Iowa City, IA, USA.

Light therapy is increasingly applied in a variety of sleep medicine and psychiatric conditions including circadian rhythm sleep disorders, seasonal affective disorder, and dementia. This article reviews the neural underpinnings of circadian neurobiology crucial for understanding the influence of light therapy on brain function, common mood and sleep disorders in which light therapy may be effectively used, and applications of light therapy in clinical practice.

J Am Geriatr Soc. 2009 Mar;57(3):441-52. Epub 2009 Jan 29.

Scheduled bright light for treatment of insomnia in older adults.

Friedman L, Zeitzer JM, Kushida C, Zhdanova I, Noda A, Lee T, Schneider B, Guilleminault C, Sheikh J, Yesavage JA.

Department of Psychiatry and Behavioral Sciences, School of Medicine, Stanford University, Stanford, California 94304, USA.

OBJECTIVES: To determine whether bright light can improve sleep in older individuals with insomnia.

DESIGN: Single-blind, placebo-controlled, 12-week, parallel-group randomized design comparing four treatment groups representing a factorial combination of two lighting conditions and two times of light administration.

SETTING: At-home light treatment; eight office therapy sessions.

PARTICIPANTS: Thirty-six women and fifteen men (aged 63.6+/-7.1) meeting primary insomnia criteria recruited from the community.

INTERVENTION: A 12-week program of sleep hygiene and exposure to bright ( approximately 4,000 lux) or dim light ( approximately 65 lux) scheduled daily in the morning or evening for 45 minutes.

MEASUREMENTS: Within-group changes were observed for subjective (sleep logs, questionnaires) and objective (actigraphy, polysomnography) sleep measures after morning or evening bright light. RESULTS: Within-group changes for subjective sleep measures after morning or evening bright light were not significantly different from those observed after exposure to scheduled dim light. Objective sleep changes (actigraphy, polysomnography) after treatment were not significantly different between the bright and dim light groups. Scheduled light exposure was able to shift the circadian phase predictably but was unrelated to changes in objective or subjective sleep measures. A polymorphism in CLOCK predicted morningness but did not moderate the effects of light on sleep. The phase angle between the circadian system (melatonin midpoint) and sleep (darkness) predicted the magnitude of phase delays, but not phase advances, engendered by bright light.

CONCLUSION: Except for one subjective measure, scheduled morning or evening bright light effects were not different from those of scheduled dim light. Thus, support was not found for bright light treatment of older individuals with primary insomnia.

Nippon Rinsho. 2009 Aug;67(8):1611-5.

Bright light therapy

[Article in Japanese]

Kamei Y.

Department of Psychiatry, Kohnodai Hospital, International Medical Center of Japan.

Bright light is a treatment of choice for seasonal affective disorder. Other indications for bright light therapy have also been tested. These include circadian rhythm sleep disorders, early-morning awakening or sleep-maintenance insomnia in elders and behavioral disturbance or insomnia in organic dementia. In these sleep disorders, the pattern of sleep-wake is misaligned with the patient’s circadian system or the external environment, resulting in insomnia. Appropriately-timed exposure to bright light can shift the sleep-wake cycle to earlier or later times, in order to correct for misalignment between the circadian system and the desired sleep-wake schedule. Evidence of the efficacy of bright light was so limited. Further research is needed to determine guidelines for the appropriate timing and safe use of bright light therapy.

Ann Acad Med Singapore. 2008 Aug;37(8):669-76.

Treatment of circadian rhythm sleep disorders with light.

Gooley JJ.

Division of Sleep Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA. jgooley@rics.bwh.harvard.edu

The human circadian system is normally synchronised with the solar day, insuring that alertness and performance peak during daytime hours and consolidated sleep occurs during the night. In circadian rhythm sleep disorders, the pattern of sleep-wake is misaligned with the patient’s circadian system or the external environment, resulting in insomnia, fatigue, and deterioration in performance. Appropriately-timed exposure to bright light can reset the timing of sleep and wake to the desired times, and improve sleep quality and daytime alertness. The efficacy of bright light therapy, however, is dependent on the time-of-day of the circadian cycle that the light is administered. In this article, we examine the physiological basis for bright light therapy, and we discuss the application of light in the treatment of circadian rhythm sleep disorders including advanced and delayed sleep-phase disorder, free-running disorder (nonentrained type), shiftwork disorder and jet lag disorder. We review the laboratory and field studies which have established bright light therapy as an effective treatment for sleep-wake and circadian misalignment, and we also provide guidelines for the appropriate timing and safe use of bright light therapy.

Chronobiol Int. 2009 May;26(4):726-39.

A personal light-treatment device for improving sleep quality in the elderly: dynamics of nocturnal melatonin suppression at two exposure levels.

Figueiro MG, Bierman A, Bullough JD, Rea MS.

Lighting Research Center, Rensselaer Polytechnic Institute, Troy, New York 12180, USA. figuem@rpi.edu

Light treatment has been used as a non-pharmacological tool to help mitigate poor sleep quality frequently found in older people. In order to increase compliance to non-pharmacological light treatments, new, more efficacious light-delivery systems need to be developed. A prototype personal light-treatment device equipped with low brightness blue light-emitting diodes (LEDs) (peak wavelength near 470 nm) was tested for its effectiveness in suppressing nocturnal melatonin, a measure of circadian stimulation. Two levels of corneal irradiance were set to deliver two prescribed doses of circadian light exposure. Eleven older subjects, between 51 and 80 yrs of age who met the selection criteria, were exposed to a high and a low level of light for 90 min on separate nights from the personal light-treatment device. Blood and saliva samples were collected at prescribed times for subsequent melatonin assay. After 1 h of light exposure, the light-induced nocturnal melatonin suppression level was about 35% for the low-light level and about 60% for the high-light level. The higher level of blue light suppressed melatonin more quickly, to a greater extent over the course of the 90 min exposure period, and maintained suppression after 60 min. The constant exposure of the low-light level resulted in a decrease in nocturnal melatonin suppression for the last sampling time, whereas for the high-light level, suppression continued throughout the entire exposure period. The present study performed with healthy adults suggests that the tested personal light-treatment device might be a practical, comfortable, and effective way to deliver light treatment to those suffering from circadian sleep disorders; however, the acceptance and effectiveness of personal light-treatment devices by older people and by other segments of the population suffering from sleep disorders in a real-life situation need to be directly tested.

Ann Acad Med Singapore. 2008 Aug;37(8):669-76.

Treatment of circadian rhythm sleep disorders with light.

Gooley JJ.

Division of Sleep Medicine, Brigham and Women’s Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA. jgooley@rics.bwh.harvard.edu

The human circadian system is normally synchronised with the solar day, insuring that alertness and performance peak during daytime hours and consolidated sleep occurs during the night. In circadian rhythm sleep disorders, the pattern of sleep-wake is misaligned with the patient’s circadian system or the external environment, resulting in insomnia, fatigue, and deterioration in performance. Appropriately-timed exposure to bright light can reset the timing of sleep and wake to the desired times, and improve sleep quality and daytime alertness. The efficacy of bright light therapy, however, is dependent on the time-of-day of the circadian cycle that the light is administered. In this article, we examine the physiological basis for bright light therapy, and we discuss the application of light in the treatment of circadian rhythm sleep disorders including advanced and delayed sleep-phase disorder, free-running disorder (nonentrained type), shiftwork disorder and jet lag disorder. We review the laboratory and field studies which have established bright light therapy as an effective treatment for sleep-wake and circadian misalignment, and we also provide guidelines for the appropriate timing and safe use of bright light therapy.

J Physiol Anthropol. 2007 Mar;26(2):113-21.

Variations in the light-induced suppression of nocturnal melatonin with special reference to variations in the pupillary light reflex in humans.

Yasukouchi A, Hazama T, Kozaki T.

Department of Physiological Anthropology, Faculty of Design, Kyushu University, Fukuoka, Japan. yasukouc@design.kyushu-u.ac.jp

The purpose of the present study was to elucidate the existence of individual differences of pupil response to light stimulation, and to confirm the reproducibility of this phenomenon. Furthermore, the relationship between the individual differences in nocturnal melatonin suppression induced by lighting and the individual differences of pupillary light response (PLR) was examined. The pupil diameter and salivary melatonin content of 20 male students were measured at the same period of time (00:00-02:30 hr) on different days, accordingly. Illumination (530 nm) produced by a monochromatic light-emitting diode (LED) was employed as the light stimulation: pupil diameter was measured with 4 different levels of illuminance of 1, 3, 30 and 600 lux and melatonin levels were measured at 30 and 600 lux (respective controls were taken at 0 lux). Oral temperature, blood pressure and subjective index of sleepiness were taken in experiments where melatonin levels were measured. Changes of the pupil diameter in response to light were expressed as PLR and light-induced melatonin suppression was expressed as a control-adjusted melatonin suppression score (control-adjusted MSS), which was compared to the melatonin level measured at 0 lux. In the PLR, the coefficients of variation obtained at 30 lux or less were large (51.5, 45.0, 28.4 and 6.2% at 1, 3, 30 and 600 lux, respectively). Correlations of illuminance of any combination at 30 lux or less were statistically significant at less than 1% level (1 vs. 3 lux: r=0.68; 1 vs. 30 lux: r=0.64; 3 vs. 30 lux: r=0.73), which showed the reproducibility of individual differences. The control-adjusted MSS at 600 lux (-1.14+/-1.16) was significantly (p<0.05) lower than that registered at 30 lux (-0.22+/-2.12). PLR values measured at 30 and 600 lux were then correlated with control-adjusted MSS; neither indicated a significant linear relationship. However, the control-adjusted MSS showed around 0 under any of the illuminance conditions in subjects with high PLR. In control-adjusted MSS of low values (i.e., melatonin secretions were easily suppressed), subjects indicated typically low PLR. In subjects with low control-adjusted MSS (n=3), characteristic changes in the autonomic nervous system, such as body temperature and blood pressure, were noted in subjects exposed to low illuminance of 30 lux. The fact that the relationship between PLR and control-adjusted MSS portray a similar pattern even under different luminance conditions suggests that MSS may not be affected in those with high PLR at low illuminance, regardless of the illuminance condition.

Clin Endocrinol (Oxf). 1998 Jan;48(1):73-9.

Bright light exposure and pituitary hormone secretion.

Kostoglou-Athanassiou I, Treacher DF, Wheeler MJ, Forsling ML.

Department of Gynaecology, St Thomas’ Hospital, UMDS, London, UK.

OBJECTIVE: Exposure to bright light inhibits melatonin secretion in man. As the relationship between melatonin and pituitary function remains controversial, we investigated the effect of altering the melatonin rhythm by bright light during the early hours of darkness on pituitary hormone secretion in man.

DESIGN: The investigation took the form of a randomized controlled clinical trial.

SUBJECTS: Ten adult healthy male volunteers, who were non-smokers and aged 21-33 years, were studied on two occasions: once during exposure to bright light from 2000 h to 0200 h and once during exposure to normal room lighting over the same period. On each day of the study, the subjects were allowed to sleep after lights were switched off at 0200 h. Observations were also performed when subjects were exposed to normal room lighting from 2000 h to 2400 h, thereafter being allowed to sleep. On each study day the subjects undertook their normal duties but refrained from taking heavy exercise and drinking alcohol. MEASUREMENTS: Serum cortisol, GH and PRL, plasma vasopressin, oxytocin, melatonin, sodium, potassium and osmolality and packed cell volume were measured over 24 hours.

RESULTS: Bright light delayed the nocturnal melatonin peak by 2 hours and resulted in a decrease in cortisol concentrations. Growth hormone levels decreased but subsequently there was a significantly greater nocturnal increase. The PRL peak was delayed and nocturnal vasopressin concentrations were lower in both the studies where subjects were exposed to a modified sleep schedule.

CONCLUSION: Exposure to bright light during the early hours of darkness delays the nocturnal melatonin peak and alters cortisol, GH, PRL and nocturnal vasopressin secretion, while modification of the sleep pattern decreases vasopressin concentrations and alters its nocturnal peak.