感觉神经动作电位波幅在糖尿病神经病中的诊断价值

Diagnostic significance of sensory nerve action potential amplitude in early-stage diabetic neuropathy

目的探讨感觉神经动作电位（SNAP）波幅及其比值在糖尿病神经病中的诊断价值。方法病例组为91例2型糖尿病患者，根据多伦多临床评分系统（TCSS）分为亚组一（无神经症状体征者51例）、二（轻度神经病变者30例）、三（重度神经病变者10例）；对照组为年龄、性别相匹配的健康对照39名。记录正中、桡浅、腓肠神经的SNAP，测量其传导速度（Vm、Vr、Vs）及波幅（Am、Ar、As），并计算腓肠-桡浅神经波幅比值（SRAR）、正中-桡浅神经波幅比值（MRAR）。结果①与对照组比较，亚组三传导速度（m／s，Vm：46．2±7．3，Vr：45．8±6．9，Vs：30．3±9．5）减慢和波幅（μV，Am：15．4±10．5，Ar：16．6±9．8，As：5．9±6．3）减低（P均〈0．05）；亚组二Vs（46．2±4．7）减慢（P=0．002）；亚组一Am（54．5±10．2）、As（13．8±5．6）和亚组二Am（33．0±14．6）、As（10．7±5．5）均减低（P均〈0．05），亚组二As更低（Z=-3．22，P=0．001）；亚组一仅SRAR（0．432±0．112）减小，亚组二MRAR（1．008±0．225）及SRAR（0．330±0．102）均减小（P均〈0．05），亚组二SRAR更小（t=-3．86，P=0．005）。②异常率：亚组一Am最高（26．0％），亚组二As最高（41．4％），As与SRAR联合其异常率（68．9％）显著高于As（Χ^2=9．212，P=0．003）。③TCSS评分与Vs（r=-0．583）、Am（r=-0．406）、A8（r=-0．620）及SRAR（r=-0．527）负相关（P均〈0．05）；SRAR（r=-0．455）及MRAR（r=-0．319）均与病程呈负相关（P均〈0．05）。结论轻度或早期糖尿病神经病，SNAP波幅较传导速度灵敏度更高；感觉传导各参数主要受病程的影响，SRAR与神经损害程度相关。

Objective To investigate the diagnostic significance of sensory nerve action protential （SNAP） on diabetic neuropathy （DN）, through measuring amplitude and amplitude ratio. Methods There were 91 patients with type 2 diabetes involing 51 cases without neurologic symptom/sign as subgroup Ⅰ , 30 cases with mild neuropathy as subgroup Ⅱ and 10 cases with severe neuropathy as subgroup Ⅲ, according to Toronto clinical scoring system （TCSS）. Thirty-nine healthy volunteers with age- and gender-matched were served as controls. SNAP were mltidromically recorded using surface electrodes. The observed parameters were as follows： conduction velocity and amplitude of median, radial and sural nerve, shorten for Vine, Vra and Vsu and Ame, Ara and Asu, respectively ; sural/radial nerve amplitude ratio （SRAR） and median/ radial nerve amplitude ratio （ MRAR ） . Results （ 1 ） As compared with the controls （ P 〈 0.05 ）, conduction velocity （m/s, Vme ： 46. 2 ± 7.3, Vra： 45.8 ± 6. 9, Vsu： 30. 3 ± 9. 5） and amplitude （μV, Am ： 15.4± 10. 5, Ar ： 16. 6± 9. 8, As ： 5.9± 6. 3） decreased significantly in subgroup Ⅲ ; Vsu （46. 2 ± 4. 7） significantly slowed in subgroup Ⅱ （ P = 0. 002 ） ; both Ame （34. 5 ± 10. 2, 33.0 ± 14. 6 ） and Asu （13.8± 5.6, 10.7 ± 5.5 ） decreased significantly in both subgroup Ⅰ and Ⅱ respectively, with Asu decreasing more significantly in subgroup Ⅲ （ Z = - 3.22, P = 0. 001 ） ; SRAR （ 0. 432 ± 0. 112 ） was significantly smaller only in subgroup Ⅰ , both SRAR （0. 330 ± 0. 102 ） and MRAR （ 1. 008 ± 0. 225 ） were significantly smaller in subgroup Ⅱ. SRAR decreased more significantly in subgroup Ⅱ （ t = - 3.86, P = 0. 003 ）. （2） The abnormal rate of Ame was the highest in subgroup Ⅰ （26. 0% ）, and Asu in subgroup Ⅱ （41.4%） ; while that of combination of Asu and SRAR （68.9%） was significantly higher than that of Asu alone （Χ^2 = 9. 212, P = 0. 003）. （3） TCSS scores were negatively related to Vsu （r = -0. 583）, Ame （ r = - 0. 406）, Asu （ r = - 0. 620） and SRAR （ r = - 0. 527, all P 〈 0.05 ）, and there was no significant correlation of TCSS scores with MRAR in subgroup Ⅱ; both SRAR （r = -0.435） and MRAR （ r = - 0. 319） were negatively related to the diabetic duration （ both P 〈 0. 05 ）. Conclusions In mild or early DN, SNAP amplitude is more sensitive than conduction velocity, combination of SRAR and Vsu may be serve as a useful indication for early diagnosis. In the DN patient, diabetic duration has more influence on the measurement of sensory NCS, and SRAR is related to the severity of neuropathy.