The roles of the contact heat evoked potential in evaluating the small nerve fibers of cranial and spinal in elderly diabetic patients / 中华老年医学杂志

ABSTRACT

Objective To study the roles of the contact heat evoked potential (CHEP) in evaluating the small nerve fibers of cranial and spinal in elderly diabetic patients,and to analyze the feature of the small fibers in order to provide scientific foundations for early diagnosis of diabetic neuropathy (DN).Methods Totally 50 diabetic patients and 40 healthy subjects were included in this study.The diabetic patients were divided into the normal nerve conduction group (n=17) and the abnormal nerve conduction group (n=33).CHEP was determined and thermal stimuli was given to the area of eyelid,forearm and peroneal.Sensory and motor nerve conduction velocity in the upper and lower limbs were tested in all diabetic patients.Results Compared with the healthy group,the N wave latencies were prolonged and the N-P amplitudes were reduced in the area of eyelid,forearm and peroneal in diabetic patients (all P＜0.01).Compared with the healthy group,the logarithm of N-P amplitudes were reduced in areas of forearm and peroneal [(1.70±0.10) vs.(1.60±0.14),(1.65±0.078) vs.(1.54±0.15),both P＜0.05] and N wave latencies were prolonged in eyelid area [(343.1±18.2) ms vs.(385.4±26.5) ms,P＜0.05] in normal nerve conduction group.Compared to group with normal nerve conduction velocity,the logarithm of N-P amplitudes was reduced in peroneal area [(1.54±0.15) vs.(1.44±0.15),P＜0.05] in abnormal nerve conduction group.Conclusions CHEP can detect the early impairment of the small fibers in elderly diabetic patients.The early smallfiber impairments in diabetic neuropathy may be axon-oriented in spinal nerves and myelin-oriented in cranial nerves.