Use of Light Therapy for Insomnia in the Elderly: Role of Circadian Rhythm Disorders

Purpose of Review: Here, we review the unique mechanisms that underlie insomnia in elderly patients and how it relates to circadian dysfunction in order to provide a practical approach to light therapy in this population. Recent Findings: While the connection between aging and insomnia has long been recognized, postmortem and recent biomarker studies have advanced our understanding of the underlying mechanisms. Most recently, studies utilizing PET tracers have supported an association of sleep disturbance with neurodegenerative changes prior to the onset of cognitive impairment. These changes may result in reduced circadian amplitude and other circadian disturbances. Recent studies added to a body of literature suggest that circadian dysfunction in elderly patients can be targeted with light therapy to improve sleep quality, timing, and duration. Summary: Circadian dysfunction plays an important role in the etiology of insomnia in the elderly. Even in the absence of cognitive decline, neurodegenerative changes in the brain are a common consequence of aging that may contribute to circadian dysfunction and insomnia generally. Light therapy may be a useful tool in addressing the underlying impact of aging on sleep and can be used in varying ways depending on the patient’s unique presentation.