Performance was evaluated with
tests of
auditory vigilance, in which the participants had to respond to a certain sound, or divided
attention tasks, in which the participants had to perform two tasks simultaneously (Roehrs et al. 2000a).
These include a
test of vision; a measure of cognition, language, motor skills, behavior,
attention and emotional reactivity; a
test of cortical
auditory processing and a measure of sleep patterns and daytime physical activity.