Morning bright light therapy for sleep to augment cognitive rehabilitation in Veterans with comorbid traumatic brain injury and post‐traumatic stress disorder: A pilot study

Abstract

Cognitive and memory impairments are often observed in disorders common to US Veterans, specifically traumatic brain injury (TBI) and post-traumatic stress disorder (PTSD). Further, sleep disturbances including excessive daytime sleepiness, insomnia, and circadian rhythm sleep disorders are highly prevalent in Veterans with TBI and/or PTSD. Sleep disturbances themselves impact cognitive function. Few therapeutic strategies exist to improve cognition, particularly in Veterans with comorbid neuropsychiatric trauma. Cognitive rehabilitative therapy is a common approach, but suffers from variable efficacy rates. Given the strong bidirectional relationship between sleep-impairments and cognitive function, we sought to investigate whether administering morning bright light therapy (MBLT) as an adjunctive therapy to improve sleep would improve response to cognitive therapy. A total of n=16 Veterans with mTBI enrolled in VA Neuropsychology based 8-week clinical, group-based cognitive rehabilitative therapy program (3 separate cohorts) were consented and randomized to either receive standard of care (CRT, n=8; 69.7±7.8 years of age; 2 female) or engage in morning bright light therapy (MBLT; 60 minutes every morning to be completed ~2 hours after waking) as an adjunctive therapy (CRT+MBLT, n=8; 63.4±11.1 years of age; 2 female). Self-report questionnaires targeting cognitive function (global, executive function, and memory), sleep, and a variety of other major domains were administered pre- and post-cognitive therapy. Veterans in the CRT+MBLT group self-reported using the lightbox >90% of all days and had a positive experience using the lightbox. Self-reported cognitive function was unchanged in the CRT group, yet significantly improved in those receiving adjunctive MBLT (p=0.004). This lack of change in self-reported cognition was coincident with no change in sleep in the CRT group. Sleep significantly improvement in the CRT+MBLT group (p=0.02). Additionally, depression and neuropsychiatric trauma symptom severity were unchanged in the CRT group, but significantly improved in the CRT+MBLT group (p<0.05). Traditional cognitive therapy shows variable rates of efficacy but may be improved with adjunctive MBLT for sleep. These data support the need for a fully powered randomized controlled clinical trial in Veterans with TBI/PTSD-related cognitive dysfunction. Additional work should also include comprehensive neuropsychological evaluations and objective metrics of sleep (e.g., wrist actigraphy or home-based polysomnography).