Cognitive performance during a night without sleep.

Sleep deprivation (SD) is a common condition that affects many people in modern life. It can interfere with cognitive abilities, motor performance, emotions and mood. Numerous studies have shown that both total and partial SD lead to impaired alertness and cognitive functioning. While a body of work has focused on the effect subsequent to SD, cognitive performance efficiency during a night without sleep has been rarely assessed. We describe the results of 6-years recording data in our laboratory. In 12h sleep deprivation (1 night from 21:00. to 09:00) a large sample of young adults has been tested in several cognitive tasks ranging from simple to complex tasks. All findings lead to conclude that: a) during the night without sleep the cognitive system generally works in a right way, allowing subjects to perform the tasks and suggesting a specific pattern of SD adaptation depending on the specific cognitive tasks; b) there is a particular moment in the night, that is at 04:00, where cognitive performance is affected, suggesting a strict association with chronobiological rhythms instead of SD; c) the cognitive performance reaches lower efficiency levels at the end of a night without sleep. Finally, we discuss the results considering the impact of SD on the social life and in particular on the shift workers.