Sleep disturbance is common in people with multiple sclerosis (MS) and contributes to diminished quality of life. Bright light therapy may be an innovative strategy to reduce sleep disturbance in MS, possibly through its effects on a subtype of retinal ganglion cells that help regulate circadian rhythms and sleep. This pilot study will evaluate whether, in people with MS, bright light therapy reduces sleep disturbance and explore whether light therapy improves function of these cells.

Multiple sclerosis (MS), an inflammatory and neurodegenerative disorder of the central nervous system (CNS), is the most common cause of progressive neurologic dysfunction in early to middle adulthood. People with MS are a markedly high risk for sleep disturbance. Estimates of the lifetime prevalence of sleep disturbance in MS reach 50%; sleep disturbance is also associated with excess MS-associated morbidity and diminished quality of life. Despite the high burden of impaired sleep and its contribution to adverse MS outcomes, effective approaches to treat and ameliorate disturbed sleep in people with MS remain poorly understood. There is unmet need to develop safe and effective rehabilitative alternatives to mitigate sleep disturbance in MS. Prior research supports the use of timed bright light therapy (LT) as one such approach for insomnia and sleepiness in those with sleep disorders or other neurologic diseases. Yet, the safety and potential effectiveness of timed LT have yet to be tested in MS. The goal of the proposed study is to conduct a detailed intervention study testing if timed bright LT in people with MS is 1) safe (primary outcome) and 2) potentially effective for reducing sleep disturbance (specifically, reducing insomnia, fatigue and improving sleep efficiency, quantity and quality as secondary outcomes). The study will also explore whether LT stimulates a novel subtype of retinal ganglion cells which are central to the regulation of circadian rhythms and sleep.

Inclusion Criteria:

• Diagnosis of MS
• Evidence of sleep disturbance
• Stable on immunomodulatory MS therapy or no therapy for at least 6 months prior to study initiation
• Stable on antidepressants for at least 3 months prior to study initiation and no evidence
• Stable on fatigue medication for at least 3 months prior to study initiation
• Willing and able to provide informed consent and follow study procedures.

Exclusion Criteria:

• Evidence of cognitive impairment
• Low risk for sleep disordered breathing
• Other comorbid ophthalmologic disorders (e.g. cataracts, glaucoma, blindness)
• Traveled across two time zones within 90 days of study screening.
• Not participating in shift work
• MS relapse or history of acute optic neuritis within 30 days
• No prior history of bipolar disorder
• No evidence of current depression
• Diagnosis of severe periodic limb movement disorder or severe restless legs syndrome

Individual participant data will not be available to other researchers. Since the study will enroll only 24 individuals, even if stripped of identifiers, it may still be possible to identify participants. Thus, data will not be shared.