Impact of exposure to dim artificial light at night during sleep on cognitive function

Abstract

Objective: Artificial light at night can impede sleep quality and can cause sleep disturbances. This study aimed to determine if dim artificial light at night (dALAN) affects cognitive function and motor performance. Methods: A total of 30 healthy young male volunteers aged 21 to 29 years were enrolled in the study. They were randomly divided into two groups depending on light intensity (Group A: 5 lux and Group B: 10 lux). After a quality control process, 23 healthy subjects were included in the study (Group A: 11 subjects, Group B: 12 subjects). Data were gathered from each participant after each night with no light (Night 1) followed by the next night (Night 2) with two different dim light conditions (5 or 10 lux) using a computerized neurocognitive function test (Vienna test). Results: In the cognitrone test, there was a significant difference in the mean time of correct Yes-response (F=9.08, p=0.007) and the mean time of correct No-response (F=7.12, p=0.014) in both Group A (5 lux) and Group B (10 lux) before and after exposure to dALAN. In the vigilance and motor performance series tests, there were no significant differences before and after exposure to dALAN in both groups, and no differences were observed between the groups. Conclusion: We found that dALAN exposure did not have a significant effect on cognition, vigilance, or motor performance; rather, the speed was faster in the cognition test after dALAN exposure.