LEWY BODY DEMENTIA INITIALLY PRESENTING AS NARCOLEPSY

Sleep disturbances have been well documented in different types of dementia. These including daytime sleepiness in Alzheimer’s disease, circadian rhythm disorders in Alzheimer disease and REM behavior disorder in Parkinson’s disease. The relationship between Narcolepsy and Lewy Body dementia is not well defined. It has been reported that hypocretin/orexin levels are low in those with Lewy-Body Dementia. Rarely has narcolepsy been reported as the presenting sign of Lewy Body Dementia. A 70-year-old Caucasian male with history of hypertension and stroke presented to clinic two years ago with complaints of falling asleep while driving. His prior in-home sleep study did not show obstructive sleep apnea. Along with persistent daytime sleepiness, he verified instances of cataplexy, sleep talking and hallucinations while sleeping at night. During this same time period, he was being worked up by Neurology for memory difficulties. MRI of brain showed mild chronic small vessel disease and know prior lacunar infarct of his basal ganglia. His blood work was otherwise unremarkable. Given his cataplexic symptoms, MSLT was performed, after repeat Polysomnogram. His polysomnogram again was normal, however, his MSLT showed REM onset sleep consistent with narcolepsy. His symptoms improved with Armodafinil. Over the course of the next year, he was eventually diagnosed with dementia of Lewy Body subtype. Just as REM behavior disorder can precede Parkinson’s disease, narcolepsy presenting in the elderly maybe a precursor to Lewy Body dementia. A larger body of evidence and more investigations are needed to definitively establish this possible relationship.