THE DISTURBANCE OF COGNITIVE-PROCESSES IN NARCOLEPSY

Neuropsychological methods have been applied by different authors to i nvestigate cognitive processes such as attention, information processi ng, memory and psychomotor performance in narcoleptic patients. A revi ew of the results strongly suggests that cognitive processes in narcol eptic patients are not impaired on a functional but only on a temporal level. Providing that short and challenging tasks were used, the perf ormance of narcoleptic patient did not differ significantly from that of healthy subjects. Performance was impaired mainly when a low and mo notonous information input had to be processed, a situation which is t ypical for tests of vigilance. This was supported by this study measur ing critical flicker fusion (CFF) at 15-min intervals for 10 hours in 10 narcoleptic patients and matched healthy controls. While peak perfo rmance did not differ between groups, narcoleptic patients were unable to perform at a steady level through the day. Tiredness and episodes of sleepiness seem to be the main reason for cognitive impairments in narcolepsy.