A randomized, double-blind, placebo-controlled trial of blue wavelength light exposure on sleep and recovery of brain structure, function, and cognition following mild traumatic brain injury

Document Type

Article

Abstract

Sleep and circadian rhythms are among the most powerful but least understood contributors to cognitive performance and brain health. Here we capitalize on the circadian resetting effect of blue-wavelength light to phase shift the sleep patterns of adult patients (aged 18-48 years) recovering from mild traumatic brain injury (mTBI), with the aim of facilitating recovery of brain structure, connectivity, and cognitive performance. During a randomized, double-blind, placebo-controlled trial of 32 adults with a recent mTBI, we compared 6-weeks of daily 30-min pulses of blue light (peak λ = 469 nm) each morning versus amber placebo light (peak λ = 578 nm) on neurocognitive and neuroimaging outcomes, including gray matter volume (GMV), resting-state functional connectivity, directed connectivity using Granger causality, and white matter integrity using diffusion tensor imaging (DTI). Relative to placebo, morning blue light led to phase-advanced sleep timing, reduced daytime sleepiness, and improved executive functioning, and was associated with increased volume of the posterior thalamus (i.e., pulvinar), greater thalamo-cortical functional connectivity, and increased axonal integrity of these pathways. These findings provide insight into the contributions of the circadian and sleep systems in brain repair and lay the groundwork for interventions targeting the retinohypothalamic system to facilitate injury recovery.

Medical Subject Headings

Actigraphy; Adolescent; Adult; Brain (pathology, physiopathology); Brain Concussion (physiopathology, psychology, therapy); Brain Mapping; Cognition; Double-Blind Method; Female; Humans; Light; Magnetic Resonance Imaging; Male; Middle Aged; Neuropsychological Tests; Phototherapy (methods); Sleep; Treatment Outcome; Young Adult

Publication Date

2-1-2020

Publication Title

Neurobiology of disease

E-ISSN

1095-953X

Volume

134

First Page

104679

PubMed ID

31751607

Digital Object Identifier (DOI)

10.1016/j.nbd.2019.104679

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