Diagnosing narcolepsy through the simultaneous clinical and electrophysiologic analysis of cataplexy.
OBJECTIVE: To demonstrate the utility of accurate clinical and electroencephalographic characterization of provoked cataplexy spells in the diagnosis of narcolepsy. METHODS: Four individuals, three with suspected and one with known narcolepsy, were clinically assessed during split-screen, video polysomnographic monitoring sessions after cataplectic events were induced by emotional provocation. RESULTS: The subjects experienced a total of nine cataplectic-like events, one occurring spontaneously (sleep paralysis) in association with a hypnagogic hallucination. During all events, the patients appeared to be sleeping with polysomnographic rapid eye movement sleep patterns, but when questioned they were able to give appropriate verbal responses. The diagnosis of narcolepsy was substantiated in all cases using standard overnight polysomnograms and multiple sleep latency tests. CONCLUSION: The diagnosis of narcolepsy can be greatly enhanced by documenting cataplexy with thorough clinical assessment and demonstration of typical rapid eye movement sleep patterns during provoked spells in the course of polysomnographic monitoring sessions.