title: Electrical impedance myography for discriminating traumatic peripheral nerve injury in the upper extremity.
abstract: OBJECTIVE
  To evaluate the potential of electrical impedance myography (EIM), which is sensitive to the changes in muscle structure and physiology, in discriminating traumatic peripheral nerve injury (TPNI) in the upper extremity. To identify factors that primarily influence muscle atrophy secondary to nerve injury.
  
  
  METHODS
  Thirty-nine patients with TPNI underwent EIM measurement and standard electromyography tests for multiple muscles in the upper extremity. The side-to-side differences in EIM parameters were calculated for each subject and compared with the compound motor action potential (CMAP) amplitude, which is a measure of injury severity, and the time since injury.
  
  
  RESULTS
  The reactance and phase values of the affected muscles were consistently lower than those of healthy muscles, with an average side-to-side difference of approximately -50% (p<0.001) and -45% (p<0.001), respectively. The CMAP amplitude, rather than the time since injury, had a greater effect on the side-to-side difference of phase values.
  
  
  CONCLUSIONS
  EIM discriminates TPNI by revealing asymmetries in reactance and phase values. The severity of injury had a larger influence than the time since injury on muscle atrophy secondary to nerve injury.
  
  
  CONCLUSIONS
  These results demonstrate the putative use of EIM in discriminating TPNI and deserves further study.
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Hand Surgery, HuaShan Hospital of Fudan University, Shanghai 200040, China.
authors.forename: Dong
authors.initials: D
authors.lastname: Tian
authors.affiliation: Department of Hand Surgery, HuaShan Hospital of Fudan University, Shanghai 200040, China.
authors.forename: Lingfen
authors.initials: L
authors.lastname: Chen
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
authors.forename: Xiaoqing
authors.initials: X
authors.lastname: Wang
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Jiang
authors.affiliation: State Key Laboratory on Integrated Optoelectronics, Institute of Semiconductors, Chinese Academy of Sciences, Beijing 100083, China. Electronic address: yudeyu@semi.ac.cn.
authors.forename: Yude
authors.initials: Y
authors.lastname: Yu
mesh_terms: D000328:Adult; D000368:Aged; D003937:Diagnosis, Differential; D017097:Electric Impedance; D004576:Electromyography / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009133:Muscular Atrophy / Q000175:diagnosis* / Q000503:physiopathology; D059348:Peripheral Nerve Injuries / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D034941:Upper Extremity / Q000294:innervation* / Q000503:physiopathology
keywords: Hand-held probe; Muscle atrophy; Muscle impedance; Nerve injury