Last century, patients with human African trypanosomiasis were described as sleepy by day and restless by night, and physicians refered to this condition as sleeping sickness. Such a description could have evoked a disturbance of circadian rhythms. However, it is only in 1989 that the first 24-hour recording was performed by our team in Niamey (Niger) in a patient with sleeping sickness. The patient was a Niger-born farm worker who had contracted the disease near Gagnoa (Cote d'lvoire). Polysomnographic recordings (electroencephalogram, EEG, electrooculogram, electromyogram, electrocardiogram, buccal and nasal airflow, and chest respiratory movements) showed a disappearance of the circadian distribution of sleep and wakefulness, which fended to occur evenly throughout day and night, with a sleep-wake alternation of approximately 80 minutes. Two investigations were conducted thereafter. The first one was done at Daloa (Cote d'lvoire) in 8 patients who were recorded during two 24-hour periods, with and without hourly blood samples the second at Brazzaville (Congo) in 10 patients recorded for 24 hours before and after treatment with melarsoprol. Aii patients were at the stage of early meningoencephalitis. At Daloa, polysomnographic recordings were taken on two 8-channel EEG machines (Alvar Minihuit, and T3-ECEM), as well as on a portable Oxford Medilog 9000 system from the same electrodes. Sleep and wake structure was altered in the most severely sick patient, the EEG trace being loaded with slow waves. Stages 1 and 2, and stages 3 and 4 could not be distinguished from one another. In the other patients, all sleep stages were easily scored. No difference was seen between recordings, regarding blood collection. All patients presented a marked disturbance in the circadian organisation of their sleep-wake cycle, this alteration being proportional to the severity of the disease. A 17-year-old patient presented a 90-minute periodic occurrence of REM sleep throughout the nychthemeron. These results were confirmed in another 10 patients recorded at Brazzaville, using 2 Alvar Minidix and two portable Oxford Medilog 9000 II systems, with continuous blood withdrawal. wrist actimetry was also taken. In parallel with the major circadian disturbance in the sleep-wake cycle observed in the most severely sick patients, wrist actimetry proved to be unable to distinguish between rest and activity episodes. These circadian disturbances were improved after the first melarsoprol treatment. The alteration of the circadian rhythmicity of sleep and wakefulness was not found in 6 healthy volunteers recorded in the same experimental conditions with an intravenous catheter to collect blood every 10 minutes. In conclusion, at the stage of meningoencephalitis, human African trypanosomiasis, sleeping sickness, represents a dysregulation of the circadian rhythm of the sleep-wake cycle, rather than a hypersomnia, which may be related to a functional and reversible alteration of the circadian body clock.
