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.