Diagnostic significance of sensory nerve action potential amplitude in early-stage diabetic neuropathy
- VernacularTitle:感觉神经动作电位波幅在糖尿病神经病中的诊断价值
- Author:
Juan BI
;
Zuneng LU
;
Hong CHU
;
Hongjuan DONG
- Publication Type:Journal Article
- Keywords:
Diabetic neuropathies;
Sural nerve;
Radial nerve;
Neural conduction;
Action potentials
- From:
Chinese Journal of Neurology
2008;41(10):657-660
- CountryChina
- Language:Chinese
-
Abstract:
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 antidromically 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, Vine : 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 Ⅱ (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 (x2 = 9. 212, P = 0. 003). (3) TCSS scores were negatively related to Van (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.
