Treating Sleep Wake Cycle Disturbances in Basal Ganglia Neurodegenerative Disorder Subjects With Ramelteon- A Double Blind, Placebo Controlled Trial

Huntington's disease (HD) is a progressively degenerative brain disorder, which results in a loss of mental and physical abilities. It is genetically determined and people carrying the HD gene invariably develop the clinical disorder at some point in their lives. HD symptoms consist of neuropsychiatric changes and motor movements. Once present, the symptoms are progressive in nature and eventually fatal. Currently there is no cure for HD.

Like HD, Parkinson's Disease (PD) and Dementia with Lewy Bodies (DLB) are also neurodegenerative disorders affecting the basal ganglia. PD and DLB are synucleinopathies - i.e., they are associated with dysfunction of the protein alpha-synuclein. Unlike HD, PD and DLB are not inherited in an autosomal dominant manner.

Sleep/wake cycles in HD, PD and DLB. HD patients, especially those in moderate to severe stages of the disease, frequently complain of difficulty falling and staying asleep. Little is known about the phenomenology and pathophysiology of sleep disturbances in HD. The few studies that have addressed this issue of sleep in HD have found disturbances in sleep architecture and sleep/wake cycles. Overall, the literature on sleep and other circadian disturbances in HD is very limited. If sleep/wake cycle disturbances in HD have pathophysiological mechanisms similar to other neurodegenerative disorders, then Ramelteon, a hypnotic agent and melatonin receptor agonist, may be beneficial in sleep/wake cycle disturbances in HD.

Sleep disruptions and circadian sleep disruptions are integral to the clinical presentation of both PD and DLB. As is true in HD, sleep disturbances in PD and DLB cause severe disruption to the patients and their caregivers' lives. In PD, sleep dysfunction occurs in approximately two thirds of patients. Sleep problems range from difficulty with sleep initiation, sleep fragmentation, disturbance of circadian rhythm, REM sleep behavior disorder (RBD), to excessive daytime sleepiness. Frequent nighttime awakening and sleep disruption are the most common sleep problems in PD. In DLB, REM sleep behavior disorder (RBD) occurs years to decades before the onset of dementia. Importantly, melatonin is one of the main treatments used for RBD. Therefore, a melatonin agonist such as Ramelteon is a natural choice for the treatment of circadian sleep disturbances in PD and DLB.

Activity monitors (actigraphs) have been used as an alternative to polysomnography (PSG). Actigraphs are small electronic motion sensors that detect movements in three axes and provide information about the subjects' activity levels over periods of days to weeks. Using validated algorithms to infer wakefulness and sleep, investigators can draw conclusions about the individuals' sleep/wake cycle patterns from their activity patterns.