Vigilance Performance and Autonomic Function in Narcolepsy: Effects of Central Stimulants

Twenty female narcoleptic patients treated with central stimulants (CS) were studied during vigilance tests and psychophysiological recordings of autonomic functions, after 3 days off CS, and during CS treatment. Results were compared with healthy female subjects. Narcoleptics were lower in Critical Flicker Fusion (CFF), but did not differ in choice reaction time or continuous vernier visual acuity. CS improved CFF in the narcoleptic group. Narcoleptics had lower skin conductance (SC) level, but did not differ from normals in SC spontaneous fluctuations or heart rate. CS did not affect SC level or heart rate in the narcoleptic group, but counteracted the decrease in SC spontaneous fluctuations normally seen over a monotonous experimental session. CS reduced lowfrequency tremor and increased high-frequency tremor in the narcoleptic group. Comparison with anxiety and psychosomatic patients was also performed. The results of the vigilance tests suggested a specific disturbance of time resolution of stimulus input in narcoleptics, not related to lowered arousal, but alleviated by CS. The psychophysiological findings suggested that narcoleptic patients have a lowered habitual arousal as well as a marked tendency to decreases in phasic arousal. Central stimulants appear to improve only the latter.