1195 Sleep-related Hallucinations

Abstract Introduction Sleep-related hallucinations, encompassing visual and auditory experiences pose a complex clinical challenge. Here, we illustrate 2 cases with diverse underlying etiologies. Report of case(s) Case 1: 76-year-old male with 3 months of nocturnal visual hallucinations, occurring 3-5 nights per week. These ranged from familiar and unfamiliar faces and characters reminiscent of movies. Symptoms occurred when waking up in the middle of the night, with difficulty returning to sleep. Polysomnography (PSG) unveiled moderate obstructive sleep apnea (OSA) without findings indicative of parasomnias and no symptoms on the night of PSG. Brain MRI revealed chronic infarcts involving right basal ganglia and bilateral optic radiations. Lesions of structures that commonly cause visual hallucinations (optic lens, retina, thalamus, midbrain) were absent. The frequency of episodes decreased to 1-2 per month after initiating CPAP therapy. Potential mechanism of improvement could be PAP mediated optimization of perfusion to the ischemic penumbra. Case 2: 93-year-old male with an eight-year history of insomnia due to musical hallucinations (MH). Auditory experiences included church and semi-classical music, with 80% being familiar tunes. The patient, a former church choir member, has a history of progressive hearing loss and tinnitus. Brain MRI/MRA revealed chronic periventricular microvascular ischemic changes. Extended EEG showed no evidence of seizures. Audiometry confirmed moderate-severe bilateral sensorineural hearing loss. No response was seen to Levetiracetam, Gabapentin, Donepezil and behavioral therapy. Home sleep study revealed severe OSA. CPAP therapy did not result in improvement of MH. MH improved significantly with Lorazepam. Hypoacusis, psychiatric disorders, focal brain lesions, epilepsy and intoxication are common etiologies for MH. The etiology in this case is very likely due to hypoacusis. The hypothesis is deafferentation resulting in release phenomenon or spontaneous activity in the auditory pathway, manifesting as MH. Conclusion Sleep-related and nocturnal hallucinations warrant a comprehensive evaluation. Differential diagnoses include neurological causes, including stroke, seizure, Multiple Sclerosis, tumor, vascular lesions, and neurodegenerative disorders. Other etiologies include psychiatric disorders, medications, alcohol, otologic and ophthalmic pathologies. It is also reasonable to evaluate for comorbid OSA as appropriate treatment may decrease the frequency of episodes and improve overall sleep in some patients. Support (if any)