接触性热痛诱发电位对糖尿病小纤维神经病变的评价作用

Effects of the contact heat evoked potential in evaluating the small fiber impairment of diabetic neuropathy

目的借助接触性热痛诱发电位（CHEP）为糖尿病神经病变的小纤维神经损害寻求一种新的无创客观定量方法。方法选取糖尿病患者46例和健康人40名，应用CHEP刺激器，控制温度52℃，分别刺激所有受试者右侧前臂、手背、小腿皮肤，采用Keypoint．net肌电图仪于Cz点分别记录N波潜伏期及N—P波波幅；同时行右侧上下肢感觉传导测定。结果健康对照组各个刺激部位CHEP的引出率为100％，而糖尿病组46例中前臂7例、手背9例、小腿16例未引出肯定CHEP波形。糖尿病组较对照组N波潜伏期延长，N—P波波幅减低。糖尿病组中25例上肢感觉传导正常，其前臂刺激Cz记录的N—P波波幅较对照组减低[分别为（34．0±12．6）、（48．4±17．5）μV，Z=-3．151，P〈0．01]，N波潜伏期差异无统计学意义；手背刺激CHEP潜伏期较对照组延长[分别为（420．4±27．8）、（407．2±24．6）ms，t=2．015，P=0．048]，波幅减低[分别为（28．2±10．1）、（43．0±16．6）pN，Z=-3．712，P〈0．01]。18例下肢感觉传导正常，其小腿刺激CHEP潜伏期延长[分别为（473．5±46．6）、（448．6±35．0）ms，t=2．219，P=0．031]，波幅减低[（23．8±7．4）、（41．5±18．5）μV，Z=-3．855，P〈0．01]。结论糖尿病患者在早期即有小纤维神经选择性受累，CHEP能够为其提供新的客观定量方法，具有潜在的临床应用价值。

Objective To investigate a non-invasive and objective measure for patients with diabetic small fiber neuropathy by contact heat evoked potential （ CHEP）. Methods CHEP was performed in diabetic patients （ n = 46） and normal subjects （ n = 40）. Thermal stimuli were given at 52 ℃ to 3 body sites： right forearm, right dorsum hand and right peroneal area. CHEP were recorded from Cz. The main components of CHEP were observed. Studies on sensory nerve conduction were performed in all the diabetic patients and the normal subjects. Results In 7 patients there were no recordable CHEP on stimulation of the forearm, and in some cases of dorsum hand （ n = 9） and the leg （ n = 16）. In contrast, CHEP were recordable in all control subjects. The diabetic group had reduced N-P amplitudes and prolonged N-wave latencies. In patients with normal sensory nerve conductions, amplitudes of CHEP were reduced and latencies of CHEP were prolonged. Twenty-five patients had normal sensory nerve conduction for upper limbs, the amplitudes of CHEP being （34.0 ± 12. 6）μV vs （48.4 ±17.5 ）μV, Z = -3. 151, P 〈 0. 01 for the forearm, （28. 2 ±10.1）μVvs （43.0±16.6）μV, Z= -3. 712, P〈0.01 for the dorsum hand with a latency of （420. 4 ±27.8 ） ms vs （ 407.2 ± 24. 6 ） ms, t = 2. 015, P = 0. 048. In 18 patients with normal sensory nerve conductions for lower limbs, the latency of CHEP for the leg was （473.5 ± 46. 6 ） ms vs （448.6±35.0） ms, t=2.219 （P=0.031） and amplitudes （23.8±7.4） μVvs （41.5 ＋18.5） μV, Z = -3. 855 （P 〈 0.01 ）. Conclusion CHEP provides an objective and non-invasive potential clinical utility in the evaluation of diabetic small fiber neuropathy.