Sleep structure changes following “ecological” cognitive training

Objectives: Past research has consistently shown that pre-sleep learning produces changes in subsequent sleep, but it remains to be clarified whether these include an increase of its quality, expressed by sleep continuity and stability measures. Moreover, studies addressing the relationship between sleep and learning usually employ declarative or procedural tasks separately, neglecting that everyday life learning depends on simultaneous activation of different memory systems. Aim of this research is to assess whether an “ecological” cognitive task intensively administered before a daytime nap would improve objective sleep quality. Methods: Sleep of 37 subjects was polysomnographically recorded in two different experimental conditions: a) CT-, in which a nap was administered at 14:30, with 2-h maximum TIB; b) CT+, in which nap, with same TIB, was preceded by an intensive training session: 18 rounds of a 2-min game whose purpose is forming as many words as possible on a grid with 16 letters, four of which are coloured and multiply total score. Results: Relative to CT-, sleep in CT+ showed a significant increase of Total Sleep Time, Actual Sleep Time, Sleep Efficiency, absolute number of spindles and a significant shortening of sleep latency. Conclusions: In agreement with previous findings, our results suggest that a learning-related factor may be considered in formulating any prediction on sleep characteristics. Also, in light of the importance of non-pharmacological treatment for sleep disorders, this study offers the possibility to explore planned cognitive training as a low-cost strategy to be integrated in behavioral therapies for sleep impairments