title: Pattern Differences of Small Hand Muscle Atrophy in Amyotrophic Lateral Sclerosis and Mimic Disorders.
abstract: BACKGROUND
  Amyotrophic lateral sclerosis (ALS) and some mimic disorders, such as distal-type cervical spondylotic amyotrophy (CSA), Hirayama disease (HD), and spinobulbar muscular atrophy (SBMA) may present with intrinsic hand muscle atrophy. This study aimed to investigate different patterns of small hand muscle involvement in ALS and some mimic disorders.
  
  
  METHODS
  We compared the abductor digiti minimi/abductor pollicis brevis (ADM/APB) compound muscle action potential (CMAP) ratios between 200 ALS patients, 95 patients with distal-type CSA, 88 HD patients, 43 SBMA patients, and 150 normal controls.
  
  
  RESULTS
  The ADM/APB CMAP amplitude ratio was significantly higher in the ALS patients (P < 0.001) than that in the normal controls. The ADM/APB CMAP amplitude ratio was significantly reduced in the patients with distal-type CSA (P < 0.001) and the HD patients (P < 0.001) compared with that in the normal controls. The patients with distal-type CSA had significantly lower APB CMAP amplitude than the HD patients (P = 0.004). The ADM/APB CMAP amplitude ratio was significantly lower in the HD patients (P < 0.001) than that in the patients with distal-type CSA. The ADM/APB CMAP amplitude ratio of the SBMA patients was similar to that of the normal controls (P = 0.862). An absent APB CMAP and an abnormally high ADM/APB CMAP amplitude ratio (≥4.5) were observed exclusively in the ALS patients.
  
  
  CONCLUSIONS
  The different patterns of small hand muscle atrophy between the ALS patients and the patients with mimic disorders presumably reflect distinct pathophysiological mechanisms underlying different disorders, and may aid in distinguishing between ALS and mimic disorders.
authors.forename: Jia
authors.initials: J
authors.lastname: Fang
authors.forename: Ming-Sheng
authors.initials: MS
authors.lastname: Liu
authors.forename: Yu-Zhou
authors.initials: YZ
authors.lastname: Guan
authors.forename: Hua
authors.initials: H
authors.lastname: Du
authors.forename: Ben-Hong
authors.initials: BH
authors.lastname: Li
authors.forename: Bo
authors.initials: B
authors.lastname: Cui
authors.forename: Qing-Yun
authors.initials: QY
authors.lastname: Ding
authors.affiliation: Department of Neurology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Li-Ying
authors.initials: LY
authors.lastname: Cui
mesh_terms: D000200:Action Potentials; D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000473:pathology* / Q000503:physiopathology; D003937:Diagnosis, Differential; D005260:Female; D006225:Hand / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology; D009133:Muscular Atrophy / Q000473:pathology* / Q000503:physiopathology; D012189:Retrospective Studies; D014897:Spinal Muscular Atrophies of Childhood / Q000473:pathology; D055009:Spondylosis / Q000473:pathology