【Abstract】Objective To investigate the correlation between cognitive function and tear secretion in patients with cognitive impairment. Methods A total of 213 inpatients were recruited in this study in the Department of Neurology at the Sixth Medical Center of Chinese PLA General Hospital from June 2021 to June 2022, including 71 with Alzheimer′s disease (AD), 75 with mild cognitive impairment (MCI), and 67 with normal cognition as controls. The cognitive function was assessed using the mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA). Schirmer test was used to measure tear secretion. SPSS statistics 25.0 was used for data analysis. Depending on data type, comparison between groups was performed using the one-way analysis of variance (ANOVA), Kruskal-Wallis test or χ² test. The correlation of cognitive function with tear secretion was analyzed using Pearson correlation analysis and Spearman′s rank correlation analysis. The receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of the results in tear Schirmer test for cognitive impairment. Results Tear secretion in AD and MCI groups were both lower than control group (P<0.01), the difference being statistically significant. There was no significant difference between the AD and MCI groups (P＞0.05). Analysis showed that results in Schirmer test had positive correlations with MMSE and MoCA scores (r=0.304,0.391;P<0.001 for both), and with each score of MoCA (P＜0.05). The area under curve(AUC) of the Schirmer test for diagnosing AD and MCI was 0.818 (P<0.001) and 0.753 (P<0.001). Conclusion Patients with cognitive impairment have reduced tear secretion, and cognition correlates with tear secretion.

This work was supported by Capital′s Funds for Health Improvement and Research (2020-2-5115).