Sleep structure and autonomic nervous function in patients with chronic insomnia combined with obstructive sleep apnea and their correlation with neuropsychological characteristics

Abstract

Objective To investigate the sleep structure and autonomic nervous function of patients with chronic insomnia combined with obstructive sleep apnea (OSA) and analyze their correlation with neuropsychological characteristics. Methods A total of 91 patients with chronic insomnia admitted to Tianjin Medical University General Hospital and Airpot Hospital from September 2019 to June 2021 were included. They were divided into simple chronic insomnia group (insomnia group, n = 46) and chronic insomnia combined with OSA group (comorbidity group, n = 45) according to whether combined with OSA. And 22 volunteers matched in sex, age and education were recruited as the control group. Sleep structure and autonomic nervous function were analyzed by PSM⁃100A sleep breathing monitoring. Subjective sleep quality was assessed by Pittsburgh Sleep Quality Index (PSQI), Epworth Sleepiness Scale (ESS) and Insomnia Severity Index (ISI). Meanwhile, neuropsychological tests were performed. Results 1) Sleep structure: total sleep time (TST; P = 0.003, 0.002), sleep efficiency (P = 0.000, 0.019), proportion of rapid eye movement (REM; P = 0.000, 0.015), mean arterial oxygen saturation (SaO2; P = 0.000, 0.000), minimum SaO2 (P = 0.000, 0.019) in the comorbidity group were lower than those in control group and insomnia group; while the wake times (P = 0.028, 0.033) and sleep apnea hypopnea index (AHI; P = 0.000, 0.000) were higher than those in control group and insomnia group. 2) Autonomic nervous function: the low frequency coupling (LFC; P = 0.000, 0.006) and LFC/high frequency coupling (HFC) ratio (P = 0.000, 0.009) in comorbidity group and insomnia group were higher than those in control group, while HFC (P = 0.000, 0.006) and PNN50 (P = 0.000, 0.047) were lower than those in control group. 3) Neuropsychological test: the comorbidity group had a lower Mini⁃Mental State Examination (MMSE) score than the control group (P = 0.000) and insomnia group (P = 0.002), and the insomnia group had a lower MMSE score than the control group (P = 0.008). In terms of memory, Auditory Verbal Learning Test (AVLT)⁃short delayed recall, long delayed recall and recognition score were lower in the comorbidity group than those in the control group (P = 0.004, 0.000, 0.000) and insomnia group (P = 0.017, 0.000, 0.000). The AVLT⁃immediate recall score in comorbidity group was lower than that in control group (P = 0.000), and the AVLT⁃immediate recall, long delayed recall and recognition score in insomnia group was lower than those in control group (P = 0.035, 0.005, 0.020). In terms of visuospatial ability, the correct number of Benton's Judgment of Line Orientation (JLO) was less in comorbidity group than in control group (P = 0.000) and insomnia group (P = 0.000), and the correct number of JLO in insomnia group was less than that in control group (P = 0.017). In terms of attention, the number of correct number of Digit Span Test (DST) backward, DST downback and Symbol Digit Modalities Test (SDMT) in comorbidity group was less than that in control group (P = 0.000, 0.000, 0.000) and insomnia group (P = 0.000, 0.000, 0.003). The correct number of DST backward and SDMT in insomnia group was less than those in control group (P = 0.003, 0.003). In terms of executive function, the correct numbers of Stroop Color⁃Word Test (SCWT)⁃A, SCWT⁃B and SCWT⁃C in the comorbidity group were less than those in the control group (P = 0.000, 0.000, 0.000) and insomnia group (P = 0.004, 0.025, 0.044). The correct numbers of SCWT⁃A, SCWT⁃B and SCWT⁃C in insomnia group were less than those in control group (P = 0.003, 0.007, 0.011). In terms of anxiety and depression, the scores of Hamilton Anxiety Scale (HAMA) and Hamilton Depression Scale (HAMD) in the comorbidity group were higher than those in control group (P = 0.000, 0.000) and insomnia group (P = 0.000, 0.000), and the scores of HAMA and HAMD in insomnia group were also higher than those in control group (P = 0.000, 0.000). 4) The correlation of sleep structure and autonomic nervous function with neuropsy hological characteristics: the TST in comorborbity group was positively correlated with the correct number of DST downback (r = 0.325, P = 0.031); the proportion of REM was positively correlated with AVLT⁃immediate recall (r = 0.302, P = 0.047), short delayed recall (r = 0.299, P = 0.049), long delayed recall (r = 0.480, P = 0.001) score, and the correct number of SCWT⁃A (r = 0.311, P = 0.040). AHI was negatively correlated with JLO (r = ⁃ 0.432, P = 0.003), the correct number of DST downback (r = ⁃ 0.370, P = 0.013), SDMT (r = ⁃ 0.449, P = 0.002), and positively correlated with HAMA (r = 0.407, P = 0.006) and HAMD (r = 0.446, P = 0.013) score. The average SaO2 was positively correlated with the correct number of DST (r = 0.397, P = 0.008), and negatively correlated with HAMA (r = ⁃ 0.370, P = 0.013) and HAMD (r = ⁃ 0.351, P = 0.020) score. The minimum SaO2 was positively correlated with the correct number of JLO (r = 0.473, P = 0.001). LFC was positively correlated with HAMA (r = 0.428, P = 0.004) and HAMD (r = 0.337, P = 0.025) score. HFC was negatively correlated with HAMA (r = ⁃ 0.428, P = 0.004) and HAMD (r = ⁃ 0.337, P = 0.025) score. The LFC/HFC ratio was positively correlated with HAMA (r = 0.415, P = 0.005) and HAMD (r = 0.308, P = 0.042) score. Conclusions Patients with chronic insomnia combined with OSA have disturbed sleep structure, autonomic imbalance and cognitive decompensation, and disturbed sleep structure and autonomic nervous function may be potential mechanisms for cognitive decompensation and mood abnormalities.

DOI: 10.3969/j.issn.1672⁃6731.2023.08.008