Abstract: Objective To explore the effect of modified uvulopalatopharyngoplasty (H-UPPP) in the treatment of obstructive sleep apnea hypopnea syndrome (OSAHS), and to observe the changes of sleep and cognitive function. 
Methods A total of 118 patients with OSAHS were included in the study and divided into observation group (n=59) and control group (n=59) according to different treatment methods. The control group received behavioral treatment, including weight control, quitting smoking and drinking, keeping a lateral position during nighttime sleep, and the observation group received H-UPPP treatment. The clinical efficacy of the two groups was observed at 6 months after treatment, and the sleep conditions ［apnea hypopnea index (AHI), lowest oxygen saturation (LSaO2), snore index (SI), Ep-worth sleepiness scale (ESS) score］ and cognitive function ［Rey-Osterrieth complex figure test (CFT) score, mini-mental state examination (MMSE) score, Montreal cognitive assessment (MoCA) score, event-related potential P300］ of the two groups were compared before and at 6 months after treatment. 
Results The therapeutic effect of observation group was better than that of control group (P＜0.05). At 6 months after treatment, AHI, SI, ESS scores and P300 latency of observation group and control group were lower than those before treatment, while LSaO2, CFT, MMSE, MoCA scores and P300 amplitude were higher than those before treatment (P＜0.05). AHI, SI, ESS scores and P300 latency were lower in the observation group than in the control group, whereas LSaO2, CFT, MMSE, MoCA score and P300 amplitude of observation group were higher than those of control group (P＜0.05). 
Conclusion H-UPPP has a good effect in the treatment of OSAHS patients, which can significantly ameliorate clinical symptoms, improve the degree of cognitive impairment, and has application value in clincial practice.

Key words: obstructive sleep apnea, modified uvulopalatopharyngoplasty, sleep, cognition