Dong-Gun Kim1, Yoon-Ho Hong2, Je-Young Shin3, Kee Hong Park4, Sung-Yeon Sohn3, Kwang-Woo Lee3, Kyung Seok Park1, Jung-Joon Sung2. 1. Department of Neurology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea. 2. Department of Neurology, Seoul Metropolitan Government Boramae Medical Center, Seoul National University College of Medicine, Seoul, Republic of Korea. 3. Department of Neurology, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Republic of Korea. 4. Department of Neurology, Gyeongsang National University Hospital, Jinju, Korea.
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.
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 ALSpatients 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 ALSpatients 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.