Limitations
pain
Several limitations should be noted when interpreting the results of this study. First, the study design did not include a habituation night for both the well-rested and sleep deprivation visits. Lifestyle restrictions demanded that each participant have a stable sleep pattern with a bedtime between 22:00 and 23:00 hours and awakening between 7:00 and 8:00 hours. Although all participants confirmed adherence at the start of each visit, it cannot be ruled out that a few participants had not followed up on these restraints. While the effect of sleep deprivation was detected for most measures, the result of the study could have been optimised by adding a habituation night [Secondly, differences in the interval between the two study visits between subjects may have influenced study outcomes. A 5-day interval was applied between the sleep deprivation visit and the subsequent well-rested visit for one group of participants. In contrast, the other group performed the well-rested and sleep-deprived visits contiguously. This may have led to a difference in familiarisation or learning effect between the two groups. If we had introduced a 5-day interval between the well-rested and the sleep deprivation periods, this potential bias could have been prevented. However, all subjects were trained during the screening period on all study procedures. Therefore, the learning and familiarisation effect during the actual study periods is expected to be small.This study was performed in young, healthy men who were considered experienced drivers. This population was chosen for pragmatic reasons as a second part of the study included determining the effects of sleep deprivation on evoked pain tests, which had to be initially restricted to a male population [The current selection of psychomotor tasks does not cover all cognitive domains which might be influenced by sleep deprivation. Other tests often used in sleep deprivation studies, such as the PVT-192 [