[Comparative study of actigraphy and ambulatory polysomnography in the assessment of adaptation to night shift work in nurses].

Night shift work is common in hospitals to assure continuous care. This practice, however, induces difficulties due to changes in the sleep/awake cycle of hospital workers. The aims of the present study were to validate actigraphy in comparison with polysomnography for sleep evaluation and to assess nurses' adaptation to sleep/wake cycles when on a permanent night shift schedule. Actigraphy and ambulatory polysomnography were performed in fifteen night shift nurses employed in hospital on a full time basis, during their work and their rest periods. Our first findings showed that actigraphy gave reliable results compared with polysomnography in evaluation of total sleep time. In addition, it was found that seven of the nurses exhibited, during their work periods, an approximately five-hour delay in the acrophase of their rest/activity rhythm compared with their rest periods. In contrast, five other nurses whose acrophase did not change between work and rest periods, exhibited sleep episodes of more than 100 minutes duration at work. These results confirm data in the literature and show that some nurses cannot adjust the circadian rhythm of their inner biological clock to their nocturnal schedules. Actigraphy seems to be an efficient, low cost and easy method for measuring total sleep time as well as for assessing the inability of nurses to adapt to permanent night shift work.