title: Pattern difference of dissociated hand muscle atrophy in amyotrophic lateral sclerosis and variants.
abstract: BACKGROUND
  Split hand is considered to be a specific feature of amyotrophic lateral sclerosis (ALS).
  
  
  METHODS
  We evaluated the pattern difference of intrinsic hand muscles of upper limb-onset ALS (UL-ALS), upper limb-onset progressive muscular atrophy (UL-PMA), brachial amyotrophic diplegia (BAD), and Hirayama disease (HD) by measuring objective electrophysiological markers.
  
  
  RESULTS
  The abductor digiti minimi (ADM)/abductor pollicis brevis (APB) compound muscle action potential (CMAP) amplitude ratio was significantly higher in UL-ALS than other variants, but a considerable proportion of UL-ALS cases had an amplitude ratio in the range of other variants. Absent APB CMAP and abnormally high ADM/APB CMAP amplitude ratio (≥4) occurred only with UL-ALS. Conversely, an absent ADM CMAP was identified only in UL-PMA and BAD.
  
  
  CONCLUSIONS
  The absolute ADM/APB CMAP amplitude ratio was not specific for ALS; however, several findings from simple electrophysiological measurements may help predict prognosis in patients with motor neuron diseases and may be early diagnostic markers for ALS.
authors: Department of Neurology, Seoul Medical Center, Seoul, Republic of Korea.
authors: Jee-Eun
authors: JE
authors: Kim
authors: Yoon-Ho
authors: YH
authors: Hong
authors: Joon-Hyung
authors: JH
authors: Lee
authors: Suk-Won
authors: SW
authors: Ahn
authors: Sung-Min
authors: SM
authors: Kim
authors: Kyung-Seok
authors: KS
authors: Park
authors: Jung-Joon
authors: JJ
authors: Sung
authors: Kwang-Woo
authors: KW
authors: Lee
authors: Seung-Yong
authors: SY
authors: Seong
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D005260:Female; D006225:Hand / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009133:Muscular Atrophy / Q000175:diagnosis* / Q000453:epidemiology* / Q000503:physiopathology; D012189:Retrospective Studies; D055815:Young Adult
keywords: amyotrophic lateral sclerosis; brachial amyotrophic diplegia, Hirayama disease; progressive muscular atrophy; split hand