24 hour polysomnographic evaluation in a patient with sleeping sickness

A 24 h polysomnographic recording was performed in a patient with sleeping sickness presenting an atypical neurological syndrome. Trypanosoma gambiense was found in a lymph gland puncture and the CSF, and a serologic immunofluorescence test was positive. The scoring technique of the polygraphic traces had to be adapted because of the presence of a permanent EEG delta wave activity during the NREM sleep stages, and the method used by Schwartz and Escande (1970) was applied. REM sleep and wakefulness presented normal polygraphic characteristics. The patient had 8 sleep episodes throughout the recording period, occurring during the daytime and at night, forming the classical diurnal sleepiness and nocturnal restlessness of sleeping sickness. All but one episode represented 1-3 complete REM-NREM sleep cycles. On all occasions, REM latency was short and 2 SOREM episodes were observed. The nychthemeral organization of the stages of vigilance differed from one state to another. Wakefulness and REM sleep had a circadian rhythmicity, while NREM sleep, total sleep time and deep sleep (corresponding to stages 3 and 4) had an ultradian periodicity. The concordance between the higher pressure for wakefulness and lower pressure for sleep around 20.00 h defined the time of occurrence of a 'forbidden zone' for sleep.