Electrical impedance myography correlates with standard measures of ALS severity

Seward B. Rutkove, James B. Caress, Michael S. Cartwright, Ted M. Burns, Judy Warder, William S. David, Namita Goyal, Nicholas J. Maragakis, Michael Benatar, Khema R. Sharma, Pushpa Narayanaswami, Elizabeth M. Raynor, Mary Lou Watson, Jeremy M. Shefner

Research output: Contribution to journalArticlepeer-review

48 Scopus citations


Introduction: Electrical impedance myography (EIM) can be used to assess amyotrophic lateral sclerosis (ALS) progression. The relationship between EIM values and standard assessment measures, however, is unknown. Methods: EIM 50 kHz phase data from 60 subjects who participated in a longitudinal natural history study of ALS were correlated with handheld dynamometry (HHD), the ALS Functional Rating Scale-Revised (ALSFRS-R) score, and motor unit number estimation (MUNE). Results: Moderate strength correlations between EIM parameters and HHD were observed for both whole-body and individual upper and lower extremity values. Similarly, moderate strength correlations were observed between EIM and ALSFRS-R upper and lower extremity subscores, but not total ALSFRS-R scores. MUNE correlated significantly with single muscle EIM data but not with whole body or upper or lower extremity values. Conclusions: These results support the concept that EIM can serve as a meaningful measure of disease severity in ALS.

Original languageEnglish (US)
Pages (from-to)441-443
Number of pages3
JournalMuscle and Nerve
Issue number3
StatePublished - Mar 2014


  • Amyotrophic lateral sclerosis
  • Biomarkers
  • Electrical impedance myography
  • Handheld dynamometry

ASJC Scopus subject areas

  • Physiology
  • Clinical Neurology
  • Cellular and Molecular Neuroscience
  • Physiology (medical)


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