Subjective and objective quality of sleep.

Relatively few studies have tried to relate subjective sleep quality to objective sleep parameters and most have been carried out in laboratory settings and often with patients and usually only for a single night. The present study used a group of 33 subjects who had sleep polysomnographically recorded in their homes for three nights during a period of several weeks. First a multiple regression analysis was carried out for each night with a 4-item sleep quality index as the dependent variable and conventional sleep parameters as predictors. This yielded a significant beta value for percent Stage 0 for each of the three nights. Sleep efficiency showed a significant correlation with sleep quality for two nights but did not enter the regression. When the night with the best and poorest sleep were compared, the only significant variable became percent SWS. It was suggested that the differing results may have been due to the large age span confusing SWS/quality correlations. [ABSTRACT FROM AUTHOR]