Association Between Peripheral Neuropathy And Cognitive Impairment In Individuals Diagnosed With Type 2 Diabetes Mellitus

【Objective】To investigate the relationship between peripheral neuropathy and cognitive impairment in patients with type 2 diabetes.【Methods】Ninety-nine in patients with type 2 diabetes mellitus(T2DM)were collected from the Department of Neurology,Affiliated Hospital of Yunnan University,between December2021 and February 2023.The damage to large peripheral nerve fibers was assessed by nerve conduction(NCS),and the damage to small sympathetic nerve fibers was assessed by skin sympathetic response(SSR).Based on the abnormalities of NCS and SSR,the subjects were divided into two groups: the diabetic peripheral neuropathy(DPN)group(n=65)and the diabetic non-peripheral neuropathy(NDPN)group(n=34).The basic information and clinical biochemical indexes were collected,and the cognitive function of the subjects was assessed by combining the Montreal Cognitive Assessment Scale(Mo CA)and the Simple Mental State Evaluation Scale(MMSE),and the correlation between DPN and cognitive impairment in T2 DM patients was analyzed by logistic regression.【Result】1.The results of NCS and SSR tests in T2 DM patients: the abnormal rates of NCS and SSR tests were 64.6% and 61.6%,and the differences were not statistically significant(P>0.05);the proportion of NCS tests that did not elicit positive waveform in the lower limbs was higher than that in the upper limbs,and the proportion of sensory nerves that did not elicit positive waveform was significantly higher than that of motor nerves,and the differences were statistically significant(P<0.05)2.The occurrence of cognitive impairment in the DPN and NDPN groups: the incidence of cognitive impairment in the DPN group was 72.31%,and the incidence of cognitive impairment in the NDPN group was 23.53%.After adjusting for confounding factors,patients with diabetic peripheral neuropathy(DPN)had a 5.974 times higher risk of cognitive impairment compared to those without DPN,and this difference was statistically significant(OR=6.974,95%CI 2.274-21.392,P=0.001<0.05).3.Mo CA and MMSE scale scores in the DPN group and NDPN group: the total score of Mo CA,visuospatial and executive,abstract,delayed recall,the total score of MMSE,structure,attention,calculation,and memory scores in the DPN group were lower than those in NDPN group,and the differences were statistically significant(P<0.05).4.The effect of abnormal NCS and SSR tests on the occurrence of cognitive impairment: Patients with abnormal NCS had a 7.762-fold increased risk of cognitive impairment compared to those with normal NCS(OR=8.762,95%CI 3.016-25.460,P<0.001),with a statistically significant difference(OR=8.762,95% CI 3.016-25.460,P<0.001);Similarly,the risk of cognitive impairment in subjects with abnormal SSR was4.455 times higher than that in normal subjects(OR=5.455,95%CI 1.862-15.979,P=0.002<0.05),with a statistically significant difference(OR=5.455 95%CI 1.862-15.979P=0.002<0.05)5.The effect of abnormal NCS parameters on the occurrence of cognitive impairment:abnormalities of NCS parameters(SNAP wave amplitude and SCV)in the lower extremities of T2 DM patients were independent factors influencing the occurrence of cognitive impairment,while upper extremity NCS parameters(SNAP wave amplitude,SCV)and extremity motor NCS parameters(compound muscle action potential(CMAP)wave amplitude,terminal motor latency(DML))were not associated with the occurrence of cognitive impairment,and the differences were not statistically significant(P>0.05)6.The effect of SSR wave amplitude and latency abnormalities on the occurrence of cognitive impairment: SSR wave amplitude and latency abnormalities in T2 DM patients were all independent influencing factors on the occurrence of cognitive impairment,and the difference was statistically significant(P<0.05).【Conclusion】1.T2 DM patients are susceptible to diabetic peripheral neuropathy(DPN),which primarily affects the lower limbs and causes sensory nerve damage more frequently than motor nerve damage.Both large and small nerve fibers can be affected.2.DPN is significantly associated with cognitive impairment in patients diagnosed with T2 DM,and it acts as an independent factor that contributes to the development of cognitive dysfunction within this population.3.The greater the severity of peripheral nerve damage in patients with diabetic peripheral neuropathy,the higher their risk for cognitive impairment.4.The risk of cognitive impairment is higher in DPN patients with extensive fibrous nerve damage compared to those with minor sympathetic nerve damage.Additionally,lower extremity involvement of sensory nerves poses a greater risk for cognitive impairment than upper extremity involvement.