The effect of intranasal instillation of insulin on cognitive function in patients with Alzheimer disease

Objective To investigate the effect of intranasal instillation of insulin with different doses on cognitive function in patients with Alzheimer disease (AD). Methods Sixty-three AD patients were collected. According to the order of doctor's office visiting, they were divided into insulin 1 group (21 cases, intranasal instillation of insulin 20 U, 2 times per day), insulin 2 group (21 cases, intranasal instillation of insulin 40 U, 2 times per day) and placebo group (21 cases, intranasal instillation of physiological saline, 2 times per day). Mini-mental state examination scale (MMSE) and Rivermead behavioural memory test second edition (RBMT Ⅱ) were used to evaluate the improvement of cognitive function after 3 months and 6 months. Results Before treatment, the scores of MMSE and RBMT Ⅱ in insulin 1 group were (20.2 ± 2.3) and (17.2±1.9) scores, in insulin 2 group were (20.7±2.8) and (16.5±1.9) scores. After treatment for 3 months, the scores of MMSE and RBMTⅡ in insulin 1 group were (21.8±3.2) and (19.2±2.0) scores , in insulin 2 group were (21.6±3.5) and (18.1±2.0) scores. The scores of MMSE and RBMTⅡ in insulin 1 group and insulin 2 group significantly improved compared with those before treatment (P <0.05 or <0.01). But the scores of MMSE and RBMT Ⅱ in placebo group were significantly aggravated, (18.9±3.8) scores vs. (20.9±2.5) scores, (15.2±2.1) scores vs. (16.1±2.0) scores,P <0.05. After treatment for 6 months, the scores of MMSE and RBMTⅡ in insulin 1 group were (22.5±3.3) and (20.5±2.0) scores, in insulin 2 group were (22.7±3.1) and(19.8±1.9) scores, and in placebo group were (17.9±4.5) and(14.7±2.0) scores. The scores of MMSE and RBMTⅡ in insulin 1 group and insulin 2 group were significantly better than those in placebo group (P <0.01). Conclusion Intranasal instillation of insulin can improve cognitive disorders in patients with AD. Key words: Insulin; Administration, intranasal; Alzheimer disease; Cognition disorders