question: Which could be some of the possible causes of hypersomnia?
answer: Sleep-wake disturbances (SWD) with hypersomnia are common after traumatic brain injury (TBI), with decreased CSF levels of hypocretin-1, a wake-promoting neurotransmitter, in cases of sleep apnea, as well as in up to half the patients with dementia, particularly in vascular dementia, Korsakow syndrome, Parkinson's disease, and depression, where the alteration of sleep architecture may be pronounced, whereas in Alzheimer's disease prominent hypersomnolence or insomnia is typically only found in later stages of the diseases.