Deficits in attention performance are associated with insufficiency of slow-wave sleep in insomnia

Objective: Cognitive impairment is associated with insomnia. However, there is a lack of evidence suggesting a link between insomnia and cognitive dysfunction in objective testing. The objectives of our current study were to assess the differences in components of attentional performance between primary insomnia patients and normal-sleeping controls and to examine potential predictors of attention impairment in patients with insomnia. Methods: We studied 36 patients (age 40.39 +/- 12.36 years; 57.1% male) with insomnia and 25 normal sleeping controls (age 39.88 +/- 12.50 years; 52.9% male) who underwent one-night polysomnography followed by Multiple Sleep Latency Test (MSLT) and Attention Network Task (ANT). ANT reflected three attentional networks termed the alerting, orienting, and executive control networks. Results: After controlling for age, gender, body mass index, depression, anxiety, and education levels, patients with insomnia scored higher on the executive control variable of the ANT compared with normal sleeping controls (96.75 +/- 7.60 vs. 57.00 +/- 10.49, p = 0.01). This higher score was independently associated with insufficiency of slow-wave sleep during nighttime sleep (beta = -0.38, p = 0.04). Conclusion: Our findings suggest that insomnia is associated with deficits in executive control of attention and that the underlying mechanism may be insufficiency of slow-wave sleep in chronic insomnia. (C) 2016 Published by Elsevier B.V.