Individual validation of model predictions of sleepiness and sleep hours.

Several mathematical models for prediction of sleepiness have been developed. Few validations on individual levels are available. The present study was designed to provide validation on the individual level of predictions using the Three Process-Model of alertness regulation. Model predictions of sleep timing were also tested. Sixteen shift workers participated in the study. Ratings of sleepiness were made every 2 h across three shifts. The model was used to predict empirical ratings using as input only information of beginning and end of work shifts, as well as using information on sleep from actigraphs (in a separate analysis). The prediction using only information on work shifts correlated r = 0.55 (p < 0.001) with empirical ratings. Predictions were generally within &#x00B1; 1 confidence interval of the ratings. Adding actigraphy sleep data improved predictions marginally. The model predictions of onset and offset of sleep were generally close to the target. It was concluded that model predictions have a rather high validity both with respect to sleepiness and to sleep timing. It is probable that other information on individual differences will further improve predictability. [ABSTRACT FROM AUTHOR]