Total sleep deprivation effect on disengagement of spatial attention as assessed by saccadic eye movements.

OBJECTIVE Previous research has shown that total sleep deprivation (TSD) of short duration (one night) affects performance to some cognitive tasks subserved by a fronto-parietal network. The aim of our study was to assess the effects of TSD on visuo-spatial attention, which is a cognitive task involving this network. Specifically, the disengagement of spatial attention was investigated with gap and overlap paradigms of saccadic eye movements. METHODS Ten healthy young male subjects performed the two tasks the morning after a normal night and after a TSD night. The study was conducted using a balanced, crossover design. RESULTS TSD significantly increased the gap effect (difference of latency between overlap and gap). CONCLUSIONS This result can be interpreted as an impaired disengagement of attention after TSD. As the peak velocity, which is an indicator of alertness, was not altered by TSD, the impairment in the disengagement of spatial attention does not result from a decrease in alertness. SIGNIFICANCE This study shows that saccadic eye movements enable studying alertness and disengagement of spatial attention simultaneously. The idea that specific brain areas are affected by TSD is confirmed by our results.