Abstract:ObjectiveTo explore the relationships between serum levels of homocysteine (Hcy) and brain-derived neurotrophic factor (BDNF) and cognitive function in patients of severe obstructive sleep apnea-hypopnea syndrome (OSAHS).MethodsSixty patients with severe OSAHS were randomly selected to evaluate their cognitive function with Montreal cognitive assessment scale (MoCA). According to the evaluation results, they were divided into cognitive impairment group (18 cases) and cognitive normal group (42 cases), and 30 healthy subjects were used as the control group. Their levels of Hcy and BDNF in serum were measured by enzyme-linked immunosorbent assay.ResultsThere were significant differences in MOCA total score, visual space and executive ability, attention, abstraction and delayed recall scores between cognitive impairment group and cognitive normal group and control group (all P < 0.01), but their differences in naming, language ability and orientation scores were insignificant (all P>0.05). The level of serum Hcy in cognitive impairment group (34.12±2.85) was higher than that in cognitive normal group (30.88±2.10), while the level of serum BDNF (9.00±1.67) was lower than that in cognitive normal group (11.64±1.73). The lowest arterial oxygen saturation (LSaO2) and apnea hypopnea index (AHI) in the cognitive impairment group were different from those in the cognitive normal group (P < 0.01). In cognitive impairment group, serum Hcy was negatively correlated with the total score of MOCA (r=-0.880, P=0.000), LSaO2 (r=-0.595, P=0.009) and BDNF (r=-0.818, P=0.000), and positively correlated with AHI (r=0.681, P=0.002). Serum BDNF was positively correlated with the total score of MOCA (r=0.751, P=0.000) and LSaO2 (r=0.521, P=0.026), and negatively with AHI (r=-0.553, P=0.017). The areas under the receiver operator characteristic curve predicted by serum Hcy and BDNF levels were 0.902 and 0.927, respectively.ConclusionThe changes of serum Hcy and BDNF levels in patients with OSAHS are related to the formation of cognitive impairment, and can be used as biomarkers for the early diagnosis and prediction of cognitive impairment.