Effects of Bright Light Therapy in Mild Traumatic Brain Injury

Effects of Bright Light Therapy of Sleep, Cognition, Brain Function, and Neurochemistry in Mild Traumatic Brain Injury

Mild traumatic brain injuries (mTBI) or "concussions" are an increasingly prevalent injury in our society. Patients with post-concussion syndrome have been shown to have deficits on tests of short term memory, divided attention, multi-tasking, information processing speed, and reaction time, as well as alteration in mood and emotional functioning. Many patients have other vague complaints including fatigue, dizziness, irritability, sleep disturbances, and chronic headaches. Furthermore, sleep disruption of one of the most common complaints in patients suffering from traumatic brain injuries, with as many as 40 to 65% of patients with mTBI complaining of insomnia. Sleep problems in these patients are associated with poorer outcome, while resolution of the sleep disturbance is associated with improvement in cognitive functioning.

Despite recent evidence of the correlation between sleep quality and recovery from traumatic brain injury, and the well-established role of sleep in neural plasticity and neurogenesis, there have been virtually no direct studies of the causal effects of sleep on recovery following mTBI. However, it is quite likely that sleep plays a critical role in recovery following brain injury.

A particularly promising non-pharmacologic approach that shows potential in improving/modifying abnormalities of the circadian rhythm and sleep-wake schedule is bright light therapy. For the proposed investigation, we hypothesize that bright light therapy may be helpful in improving the sleep of patients with a recent history of mTBI and may also have other mood elevating effects, both of which should promote positive treatment outcome in these individuals. Bright light therapy may increase the likelihood that they will recover more quickly, benefit more extensively from other forms of therapy, and build emotional and cognitive resilience.

Inclusion Criteria:

• Age range between 18 and 50.
• Subjects must be right handed.
• The primary language of the subjects must be English.
• Subjects have experienced a "concussion" or mTBI within the preceding 18 months, but no sooner that 4 weeks prior to their screening. The occurrence of a concussion or mTBI must be documented by a medical report or other professional witness documentation.
• If documented, Glasgow Coma Scale in the range of 13-15 following the injury.
• Subjects must have complaints of sleep difficulties that emerged or worsened following the most recent head injury.
• At least half of subjects must have evidence of sleep onset insomnia or delayed sleep phase disorder.

Exclusion Criteria:

• Any other history of neurological illness, current Diagnostic and Statistical Manual (DSM-IV) Axis I disorder, lifetime history of psychotic disorder, or head injury with loss of consciousness > 30 minutes
• Complicating medical conditions that may influence the outcome of neuropsychological assessment or functional imaging (e.g., HIV, brain tumor, etc.)
• Mixed or left-handedness
• Abnormal visual acuity that is not corrected by contact lenses
• Contraindicated conditions noted by the manufacture of the light device such as the use of photosynthesizing medications, history of cataract surgery, and pre-existing eye conditions.
• Metal within the body, claustrophobia, or other contraindications for neuroimaging
• Less than 9th grade education
• Excess current alcohol use (more than 2 instances of intake of 5+ drinks (men) when or 4+ drinks (women) when drinking in the past two months, and/or on average drinking > 2 drinks per day (men); > 1 drinks per day (women) during the past two months
• History of alcoholism or substance use disorder
• Significant use of illicit drugs
• History of marijuana use within the past 6 weeks, use of marijuana before the age of 16, and/or use of > 20 marijuana cigarettes throughout the participant's lifetime.
• Subjects who engage in shift-work, night work, or who have substantially desynchronized work-sleep schedules (i.e., sleeping later than 10:00 a.m. more than once a week) will be excluded