Split-hand sign in the patients with amyotrophic lateral sclerosis / 中华神经科杂志

ABSTRACT

Objective To investigate the diagnostic value of the split-hand sign in amyotrophic lateral sclerosis ( ALS).Methods Ninety ALS patients, 41 patients with other neuromuscular disorders and 71 normal controls were recruited for conventional nerve conduction study.Compound muscle action potential ( CMAP) amplitude recorded from abductor pollicis brevis ( APB) , abductor digiti minimi ( ADM) and first dorsal interosseous (FDI), CMAP amplitude ratios, CMAP amplitude differences and split-hand index ( SI) were analyzed.Results The APB/ADM CMAP amplitude ratio was significantly lower in the ALS patients (0.44(0.44)) than that in the patients with other neuromuscular disorders (1.31(0.87);z=6.967, P<0.01) and the normal controls (0.99(0.42);z=7.687, P<0.01).The FDI/ADM CMAP amplitude ratio was significantly decreased in the ALS patients ( 0.79 ( 0.46 ) ) compared with that in the normal controls ( 1.23 ( 0.39 ); z =5.899, P <0.01 ).The FDI/ADM CMAP amplitude ratio was comparable between the ALS patients and the patients with other neuromuscular disorders ( 0.93 ( 0.62 );z=1.737,P=0.081).SI was significantly lower in the ALS patients (2.42 (3.14)) than that in the patients with other neuromuscular disorders (10.10(6.54);q=7.947, P<0.05) and the normal controls (17.93(8.32);q=10.827, P<0.05).SI <5.2 can help differentiate ALS from mimic disorders, with a sensitivity of 83.33% and specificity of 96.43%.Conclusions The split-hand sign appears to be a specific feature of ALS.SI robustly differentiates ALS from mimic disorders and potentially facilitates an earlier diagnosis of ALS.