[Narcolepsy and activity monitor]

By means of a wrist accelerometer, motor activity of 14 narcoleptic patients was continuously monitored. The accelerometer registered accelerations exceeding a threshold value of 0.1 gr and stored activity integrated over 3 minutes. After a registration period of 20 days, the data were read out, graphically displayed and compared to the patient's diary. Interruptions of night sleep and some sleep attacks during day correlated closely with the patient's diary. However, sleep attacks of less than about 5 minutes duration were not identified, because they could not be differentiated from normal rest. Except for that, activity monitoring with this accelerometer is a useful and simple method for ambulatory activity recording in narcoleptics.