Mild traumatic brain injuries (mTBI) or "concussions" are an increasingly prevalent injury in
the investigators 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, the investigators 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.
This study will also have a healthy control (HC)/effect localization arm that will assist in
identifying and mapping the brain systems before and after light exposure so that researchers
may develop further insights into the relationship between concussion, light exposure, sleep,
and brain function. This healthy control arm will also provide brain targets for study in the
analysis of the Main Study Arm.
- 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
- 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
- Any other history of neurological illness, current Diagnostic 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
- 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