Psychomotor Vigilance Task (RTTT)

Volunteers were screened by telephone. After screening, the eligible participants and the general practitioner received a medical questionnaire for the verification of the drug usage. Once enrolled in the study, the subjects attended a training day to familiarize them with the experimental procedures. The actual testing day was one week later and included the tests Risk Taking Test Traffic (RTTT), Trailmaking A and B (TMT-A and TMT-B), Digit Symbol Substitution Task (DSST), Reaction test (RT 1,2 and 3), Determination Test (DT) and Psychomotor vigilance task(PVT).
Participant’s sleep complaints were evaluated using Dutch versions of the Pittsburgh Sleep Quality Index (PSQI) (Buysse et al. 1989) and the Groningen Sleep Quality Scale (GSQS)

24 different traffic situations were displayed to the subjects. The participants were asked to push a button at the moment they would not execute the task of the situation anymore because it became too dangerous. (Hergovich, Arendasy, Sommer, & Bognar, 2007).
Trailmaking A and B (TR A and TR B) The TMT is a pen-on-paper test which provide information about selective- and divided attention and executive functions. The test consists of two parts. In part A the participant was instructed to connect 25 numbers as soon as possible in sequential order by drawing a line. Part B should be carried out in the same way as part A. The only difference is that the targets of part B are not only numbers but also letters and should have to be connected in the following way: 1-A-2-B-3-C etc. The primary outcomes of both parts are the time that a participant needed to complete the task and the number of

The test measures a combination of stress tolerance, divided attention, mental flexibility and reaction time. This was done by providing the participant a number of stimuli on which they had to react in different ways. These stimuli consisted of colored spots, auditory signals and foot signals. The speed of the test presenting stimuli was adapted to the reaction time of the participant. Stress was caused by providing stimuli in which the participant can’t give optimal response. The primary outcome is the median reaction time and correct responses. The duration of the test is approximately 4 minutes.
Psychomotor vigilance task (PVT) The PVT (Dinges and Powell 1985) is based on a visual RT test. The visual stimulus was a counter which turned on at random intervals between 2 and 10 seconds. The subject was required to respond by pressing a button when the counter turned on. In response to the subject’s button press, the counter display stopped. The main performance parameters that are used are the reaction time and number of lapses (= Response Time ≥500 msec). The test duration is 10