Extracting interaction effect of cognitive task and unwanted cognitive activity in pre-sleep period

Abstract

Abstract-The difficulty of switching off unwanted pre-sleep cognitive activities always causes most people with insomnia unable to fall asleep. Previous studies suggested that manipulating pre-sleep thoughts with cognitive task could change sleep onset latency. The interaction effect of cognitive task and unwanted thoughts is a mixed effect in which each mechanism alone is not completely understood. The present study tries to explore the mixed effect and extract the single effect from it. Seven people with insomnia were investigated and the general cognitive task controlled internally by insomniacs themselves was replaced with an audio task in which the participants have to react distinctively to two different auditory stimuli. The reaction time for which reflected the interaction effect was recorded and then analyzed by the autocorrelation and partial autocorrelation method. A general decline tendency which is called decline effect was observed in the single effect and for most insomniacs the length of the decline effect was around 4 or 5 seconds. In addition, it indicated that such decline effect could be a potential candidate for investing the correlation between cognitive load and interaction effect.