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Split‐hand phenomenon in amyotrophic lateral sclerosis: A motor unit number index study
Author(s) -
Kim DongGun,
Hong Yoonho,
Shin Jeyoung,
Park Kee Hong,
Sohn SungYeon,
Lee KwangWoo,
Park Kyung Seok,
Sung JungJoon
Publication year - 2016
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.24958
Subject(s) - amyotrophic lateral sclerosis , compound muscle action potential , motor unit , medicine , snap , electromyography , hand muscles , anatomy , electrophysiology , physical medicine and rehabilitation , disease , computer graphics (images) , computer science
The split‐hand phenomenon refers to preferential wasting of the thenar muscles with relative sparing of the hypothenar muscles in amyotrophic lateral sclerosis (ALS). Methods: We compared the split‐hand index (SI) calculated from the compound muscle action potential (CMAP; SI CMAP ) with that calculated from the motor unit number index (MUNIX; SI MUNIX ). We performed MUNIX on the abductor policis brevis (APB), first dorsal interosseous (FDI), and abductor digiti minimi (ADM) muscles of 39 ALS patients and 40 age‐matched, healthy controls. SI is derived by multiplying the CMAP (or MUNIX) recorded over the APB and FDI and dividing by the CMAP (or MUNIX) recorded over the ADM. Results: Receiver‐operating characteristic curve analysis revealed good diagnostic accuracy for both indices, but better performance of SI MUNIX than SI CMAP . Conclusion: SI MUNIX and SI CMAP were useful in differentiating ALS patients from healthy controls. SI MUNIX appears to be a better electrophysiological marker than SI CMAP for the split‐hand sign of ALS. Muscle Nerve 53 : 885–888, 2016