Slow wave sleep (SWS) distribution across night sleep episode in the elderly

Slow wave sleep (SWS) distribution across night sleep was shown to be diffe rent between infants and young adults. The present research aimed at studyi ng the SWS distribution across night sleep in elderly subjects. Nine health y elderly subjects, 61-71 years old, were submitted to nocturnal polygraphi c sleep recording. Eleven young subjects, 21-23 years old, were the control group. Recordings were visually analyzed according to Rechtschaffen and Ka les rules; the method proposed by Webb and Dreblow was used for scoring SWS . An NREM-REM cycle was defined as a sequence of NREM and REM sleep not int errupted by a waking period longer than 15 minutes. SWS percentage was calc ulated for each successive NREM episode. No significant association between SWS percentage and cycle rank was shown in elderly subjects, whereas a sig nificant association was observed in the young ones. This kind of SWS distr ibution could be interpreted as reflecting the restructuring of internal or ganization of sleep in the elderly. (C) 1998, Editrice Kurtis.