Diagnostic significance of ulnar/median compound muscle action potentials amplitude ratio in motor neuron disorders
10.3760/cma.j.issn.1006-7876.2013.05.005
- VernacularTitle:尺神经与正中神经复合肌肉动作电位波幅比值在运动神经元病变中的诊断价值
- Author:
Wenhua WANG
;
Ying LUO
;
Yanchun XIE
;
Hong CHU
;
Hongjuan DONG
;
Zheman XIAO
;
Zuneng LU
- Publication Type:Journal Article
- Keywords:
Amyotrophic lateral sclerosis;
Action potentials;
Ulnar nerve;
Median nerve
- From:
Chinese Journal of Neurology
2013;(5):304-307
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate prospectively the diagnostic significance of ulnar/median nerve amplitude ratio in motor neuron disorders.Methods Patients referral to our department between May 2009 and February 2012,due to muscle weakness,inflexible,cramps and atrophy,were consecutively enrolled.Conventional nerve conduction studies of 4 extremities (using surface electrodes) and needle electromyography were performed in all patients with fixed examiner.The compound muscle action potentials (CMAP) were recorded from abductor digiti minimi (ADM) and abductor pollicis brevis (APB) with stimulation of ulnar and median nerve at wrist,respectively.Moreover,the ratio of CMAP amplitude between ADM and APB (ADM/APB) was calculated in the patients who met the diagnostic criteria for definite amyotrophic lateral sclerosis (ALS) and Hirayama disease (HD).The patients with Guillain-Barré syndrome (GBS) and other popyneuropathies (PN) were served as case-controls,and 34 healthy volunteers (aged (45.7 ± 16.3) years) as normal-controls.Results (1) There were 78 cases with ALS,25 HD,51 GBS and 140 other PN,with the mean age(years) of 54.7 ± 11.6,17.6 ± 2.2,41.3 ± 18.4 and 57.1 ± 14.3,respectively.(2) ADM/APB in the ALS subgroup was 2.28 ±2.87 (0.12-22.38),HD0.66±0.36 (0.05-1.34),GBS 1.42 ± 1.33 (0.25-9.85),other PN 1.36 ± 1.48 (0.08-14.44) and normal-controls 1.07 ± 0.28 (0.61-1.64,F =6.872,P =0.000),respectively.(3) The areas under receiver operator characteristic curve in patients with ALS was 0.830 (s-x =0.039) and HD 0.691 (sx =0.039,P =0.000) ; the diagnostic sensitivity and specificity for ALS patients were 36.7％ and 93.3％,respectively,with cutoff value of ADM/APB =2; and the diagnostic sensitivity and specificity for HD patients were 53.6％ and 89.0％,respectively,with cutoff value of ADM/APB =0.7.Conclusions The ulnar/median CMAP amplitude ratio increases in ALS,but decreases in HD,which may be served as a relatively specific electrophysiological index.ADM/APB amplitude ratio ＞ 2.0 is suggested to be a diagnostic parameter for ALS and ＜ 0.7 for HD.
