BALTIMORE—Bright light therapy may improve sleep, cognition, emotion, and brain function following mild traumatic brain injury (TBI), according to research presented at the 27th Annual Meeting of the Associated Professional Sleep Societies.
Results show that six weeks of morning bright light therapy resulted in a marked decrease in subjective daytime sleepiness. This improvement was further associated with improvements in the propensity to fall asleep and nighttime sleep quality. Bright light therapy also affected depressive symptoms.
“Our preliminary data suggest that morning bright light therapy might be helpful to reduce subjective daytime sleepiness and to improve nighttime sleep,” said Mareen Weber, PhD, Instructor in Psychiatry at McLean Hospital/Harvard Medical School in Belmont, Massachusetts. “Importantly, the research also shows changes in brain activation during a demanding cognitive task, suggesting that bright light treatment might yield changes in brain functioning.”
The study group included 18 patients with a documented history of at least one mild TBI and sleep disturbance that either emerged or was aggravated with the most recent injury. Data were gathered using Multiple Sleep Latency Tests (MSLT), actigraphy, and sleep diaries, and all participants underwent MRI and comprehensive psychiatric and neuropsychologic assessments before and after the intervention.
According to the authors, at least 50% of individuals with TBI experience some kind of sleep disturbance following their injury, and sleep has been demonstrated to be essential for brain plasticity and may be important for recovery.
“Improving sleep following mild TBI could prove critical to maximizing recovery from the injury,” said Dr. Weber. “Furthermore, bright light therapy is easy and minimally invasive, requires no medication, and has no known serious side effects.”
Melatonin May Improve Sleep and Cognition at High Altitudes
A new study conducted on North America’s highest mountain peak suggests that melatonin helps improve sleep and cognition at high altitudes.
After taking melatonin, participants fell asleep faster and experienced less wakefulness following sleep onset than after taking a placebo. Furthermore, in comparison with placebo treatment, mean reaction time the day after taking melatonin was significantly improved.
“Surprisingly, climbers in this study who were administered a placebo took approximately 44 minutes to fall asleep,” said Christopher Jung, PhD, Assistant Professor in the Sleep and Chronobiology Lab of the Department of Biological Sciences at the University of Alaska Anchorage. “After taking melatonin, it took them only approximately 20 minutes to fall asleep, and this increase in sleep was likely a significant factor in improving cognitive performance.”
The randomized, placebo-controlled study involved 13 climbers who were evaluated on two consecutive nights at 14,200 feet on Mt. McKinley, which has a summit elevation of 20,320 feet. In the double blind, crossover, within-subjects design, participants took melatonin 90 minutes prior to their chosen bedtime on one night, and they took a placebo at the same time on the other night. Participants slept in their own tents, and a wireless sleep-recording device was used to quantify sleep quality. During the day after the two test nights, cognitive performance was measured using a computerized version of the Stroop test to assess mean reaction time.
According to the authors, high altitude exposure is associated with hypoxia-related sleep disruption and decrements in cognition that can be especially problematic in extreme conditions.
“Many high altitude climates are extreme and dangerous, often requiring split-second decisions to be made during climbing and military operations,” said Dr. Jung. “Based on these results, melatonin is a safe and natural supplement that improves cognitive function and sleep at high altitude.”
Insomnia May Cause Dysfunction in Emotional Brain Circuitry
A new study provides neurobiologic evidence for dysfunction in the neural circuitry underlying emotion regulation in people with insomnia, which may have implications for the risk relationship between insomnia and depression.
“Insomnia has been consistently identified as a risk factor for depression,” said Peter Franzen, PhD, an Assistant Professor of Psychiatry at the University of Pittsburgh School of Medicine. “Alterations in the brain circuitry underlying emotion regulation may be involved in the pathway for depression, and these results suggest a mechanistic role for sleep disturbance in the development of psychiatric disorders.”
The study involved 14 individuals with chronic primary insomnia without other primary psychiatric disorders, as well as 30 good sleepers who served as a control group. Participants underwent an fMRI scan during an emotion regulation task in which they were shown negative or neutral pictures. They were asked to passively view the images or to decrease their emotional responses using cognitive reappraisal, a voluntary emotion regulation strategy in which a person interprets the meaning depicted in the picture to feel less negative.