Reliability and validity of the Medical Research Council (MRC) scale and a modified scale for testing muscle strength in patients with radial palsy.

Authors

  • Tatjana Paternostro-Sluga
  • Martina Grim-Stieger
  • Martin Posch
  • Othmar Schuhfried
  • Gerda Vacariu
  • Christian Mittermaier
  • Christian Bittner
  • Veronika Fialka-Moser

DOI:

https://doi.org/10.2340/16501977-0235

Keywords:

manual muscle strength testing, Medical Research Council scale, peripheral nerve lesion, radial palsy.

Abstract

OBJECTIVE: To assess the inter-rater and intra-rater reliability and validity of the original and a modified Medical Research Council scale for testing muscle strength in radial palsy. DESIGN: Prospective, randomized validation study. PATIENTS: Thirty-one patients with peripheral paresis of radial innervated forearm muscles were included. METHODS: Wrist extension, finger extension and grip strength were evaluated by manual muscle testing. Dynamometric measurement of grip strength was performed. Pair-wise weighted kappa coefficients were calculated to determine inter-rater and intra-rater reliability. The 2 scores were compared using the signed-rank test. Spearman's correlation coefficients of the maximal relative force measurements with the median (over-raters) Medical Research Council and modified Medical Research Council scores were calculated to determine validity. RESULTS: Inter-rater agreement of the Medical Research Council scale (finger extension: 0.77; wrist extension: 0.78; grip strength: 0.78) and the modified Medical Research Council scale (finger extension: 0.81; wrist extension: 0.78; grip strength: 0.81) as well as intra-rater agreement of the Medical Research Council scale (finger extension: 0.86; wrist extension: 0.82; grip strength: 0.84) and the modified Medical Research Council scale (finger extension: 0.84, wrist extension: 0.81; grip strength: 0.88) showed almost perfect agreement. Spearman's correlation coefficients of the maximal relative force measurements with the median Medical Research Council and modified Medical Research Council score were both 0.78. CONCLUSION: Medical Research Council and modified Medical Research Council scales are measurements with substantial inter-rater and intra-rater reliability in evaluating forearm muscles.

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Published

2008-07-15

How to Cite

Paternostro-Sluga, T., Grim-Stieger, M., Posch, M., Schuhfried, O., Vacariu, G., Mittermaier, C., Bittner, C., & Fialka-Moser, V. (2008). Reliability and validity of the Medical Research Council (MRC) scale and a modified scale for testing muscle strength in patients with radial palsy. Journal of Rehabilitation Medicine, 40(8), 665–671. https://doi.org/10.2340/16501977-0235

Issue

Section

Case Report