RÉSUMÉ
Objective To evaluate the objective sleep status of patients with chronic insomnia by cardiopulmonary coupling (CPC) technique, and evaluate the characteristics of cognitive dysfunction to explore the correlation between objective sleep and cognitive dysfunction in patients with chronic insomnia. Methods Forty-three patients with chronic insomnia, admitted to our hospital from October 2017 to April 2019, were enrolled in our study;15 age-, gender-and education-matched healthy volunteers were recruited as control group. All subjects followed their daily routine at home and completed CPC examination. Montreal Cognitive Assessment (MoCA), Auditory Vocabulary Learning Test (AVLT), Trail Making Test (TMT) and Stroop Color Word Test were used to evaluate the general and single cognitive functions, respectively. The correlation of objective sleep with cognitive function was analyzed. Results (1) As compared with those in the control group, high frequency coupling (stable sleep) ratio was significantly decreased, low frequency coupling (un-stable sleep) ratio and extremely low frequency coupling (rapid-eye-movement sleep/waking) ratio were significantly increased, and latency of high frequency coupling was significantly prolonged in chronic insomnia group (P<0.05). (2) Chronic insomnia group had significantly lower MoCA total scores than control group (P<0.05), specifically manifested as decrement of visuospatial ability and execution and attention abilities; specific cognitive test showed that chronic insomnia group performed worse in immediate recall, and had delayed recall of AVLT, longer time consumption in TMT-B, smaller number of wired arrival numbers, and longer time consumption in Stroop color word test than the control group, with significant differences (P<0.05). (3) There was a correlation between CPC sleep structure and Cognitive Function Scale scores in patients with chronic insomnia. Conclusion In patients with chronic insomnia, stable sleep is reduced, un-stable sleep and rapid-eye-movement sleep/waking are increased; the impaired cognition domains are visual space and executive function, attention and memory; disturbed sleep structure aggravates the memory and execution impairment of patients with chronic insomnia.