Split‐hand phenomenon in amyotrophic lateral sclerosis: A motor unit number index study |
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| Authors: | Dong‐Gun Kim MD Je‐young Shin MD Kee Hong Park MD Sung‐Yeon Sohn MD Kwang‐Woo Lee MD Kyung Seok Park MD Jung‐Joon Sung MD |
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| Affiliation: | 1. Department of Neurology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea;2. Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea;3. Department of Neurology, Gyeongsang National University Hospital, Jinju, Korea |
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| Abstract: | Introduction: 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; SICMAP) with that calculated from the motor unit number index (MUNIX; SIMUNIX). 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 SIMUNIX than SICMAP. Conclusion: SIMUNIX and SICMAP were useful in differentiating ALS patients from healthy controls. SIMUNIX appears to be a better electrophysiological marker than SICMAP for the split‐hand sign of ALS. Muscle Nerve 53 : 885–888, 2016 |
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| Keywords: | amyotrophic lateral sclerosis compound muscle action potential MUNIX split hand split index motor unit number index |
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