title: Hypersomnia associated with a focal pontine lesion.
abstract: A 50-year-old woman developed intractable excessive sleepiness after undergoing the surgical removal of a brainstem cholesteatoma. The 24-hour ambulatory monitoring revealed a normal architecture of sleep contents, with 62.7% of the time spent in sleep. Auditory and somatosensory evoked responses showed abnormal patterns. The MRI scan of her brain showed an extensive nonprogressive lesion in the brainstem. We speculate that the problem underlying the patient's hypersomnia is a defect in the ascending reticular activating system (ARAS) rather than in the REM and NREM sleep mechanisms.
authors.affiliation: Evoked Potential Laboratory, Terrebonne General Medical Center, Houma, Louisiana, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Ganji
authors.forename: G S
authors.initials: GS
authors.lastname: Ferriss
authors.forename: J
authors.initials: J
authors.lastname: Rao
authors.forename: J
authors.initials: J
authors.lastname: Furlow
mesh_terms: D002781:Cholesteatoma / Q000503:physiopathology / Q000601:surgery*; D006970:Disorders of Excessive Somnolence / Q000209:etiology* / Q000503:physiopathology; D004292:Dominance, Cerebral / Q000502:physiology; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology; D005073:Evoked Potentials, Somatosensory / Q000502:physiology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D017286:Polysomnography; D011149:Pons / Q000503:physiopathology / Q000601:surgery*; D011930:Reaction Time / Q000502:physiology; D012894:Sleep Stages / Q000502:physiology