Fixed dynamometry is more sensitive than vital capacity or ALS rating scale

Patricia L. Andres, Margaret Peggy Allred, Helen E. Stephens, Mary Proffitt Bunnell, Catherine Siener, Eric A. Macklin, Travis Haines, Robert A. English, Katherine A. Fetterman, Edward J. Kasarskis, Julaine Florence, Zachary Simmons, Merit E. Cudkowicz

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


Introduction: Improved outcome measures are essential to efficiently screen the growing number of potential amyotrophic lateral sclerosis (ALS) therapies. Methods: This longitudinal study of 100 (70 male) participants with ALS compared Accurate Test of Limb Isometric Strength (ATLIS), using a fixed, wireless load cell, with ALS Functional Rating Scale-Revised (ALSFRS-R) and vital capacity (VC). Results: Participants enrolled at 5 U.S. sites. Data were analyzed from 66 participants with complete ATLIS, ALSFRS-R, and VC data over at least 3 visits. Change in ATLIS was less variable both within- and among-person than change in ALSFRS-R or VC. Additionally, participants who had normal ALSFRS-R arm and leg function averaged 12 to 32% below expected strength values measured by ATLIS. Conclusions: ATLIS was more sensitive to change than ALSFRS-R or VC and could decrease sample size requirements by approximately one-third. The ability of ATLIS to detect prefunctional change has potential value in early trials. Muscle Nerve 56: 710–715, 2017.

Original languageEnglish
Pages (from-to)710-715
Number of pages6
JournalMuscle and Nerve
Issue number4
StatePublished - Oct 2017

Bibliographical note

Publisher Copyright:
© 2017 Wiley Periodicals, Inc.


  • ALS
  • longitudinal
  • outcome measure
  • strength
  • vital capacity

ASJC Scopus subject areas

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


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