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Updated: Mar 31, 2026
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Utility of Dissociated Intrinsic Hand Muscle Atrophy in the Diagnosis of Amyotrophic Lateral Sclerosis
Published on: March 4, 2014
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Split-hand phenomenon in amyotrophic lateral sclerosis: A motor unit number index study
Dong-Gun Kim1, Yoon-Ho Hong2, Je-Young Shin3
1Department of Neurology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea.
Muscle & Nerve
|October 29, 2015
Summary
The split-hand sign in amyotrophic lateral sclerosis (ALS) can be detected using electrophysiological markers. The motor unit number index (MUNIX) shows better diagnostic accuracy than compound muscle action potential for identifying this sign in ALS patients.
Area of Science:
- Neurology
- Electrophysiology
- Biomarkers
Background:
- The split-hand phenomenon, characterized by thenar muscle wasting with relative hypothenar sparing, is a clinical sign in amyotrophic lateral sclerosis (ALS).
- Accurate electrophysiological assessment is crucial for diagnosing ALS and its specific clinical signs.
Purpose of the Study:
- To compare the diagnostic performance of two electrophysiological indices for the split-hand sign in ALS.
- To evaluate the utility of the split-hand index derived from compound muscle action potential (SICMAP) versus motor unit number index (SIMUNIX).
Main Methods:
- The study involved 39 ALS patients and 40 healthy controls.
- The split-hand index (SI) was calculated using both CMAP and MUNIX for the abductor policis brevis (APB), first dorsal interosseous (FDI), and abductor digiti minimi (ADM) muscles.
- Receiver-operating characteristic (ROC) curve analysis was employed to assess diagnostic accuracy.
Main Results:
- Both SIMUNIX and SICMAP demonstrated good diagnostic accuracy in differentiating ALS patients from controls.
- SIMUNIX exhibited superior performance compared to SICMAP in identifying the split-hand sign.
Conclusions:
- Both SIMUNIX and SICMAP are valuable electrophysiological markers for the split-hand sign in ALS.
- SIMUNIX is proposed as a more effective electrophysiological marker than SICMAP for the split-hand sign in amyotrophic lateral sclerosis.
Keywords:
MUNIXamyotrophic lateral sclerosiscompound muscle action potentialmotor unit number indexsplit handsplit indexMore Related Videos
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