Motor unit number index (MUNIX) versus motor unit number estimation (MUNE): a direct comparison in a longitudinal study of ALS patients

Werner A Boekestein, Helenius J Schelhaas, Michel J A M van Putten, Dick F Stegeman, Machiel J Zwarts, Johannes P. van Dijk

Research output: Contribution to journalArticleAcademicpeer-review

79 Citations (Scopus)

Abstract

OBJECTIVE: To evaluate how the motor unit number index (MUNIX) is related to high-density motor unit number estimation (HD-MUNE) in healthy controls and patients with amyotrophic lateral sclerosis (ALS).

METHODS: Both MUNIX and HD-MUNE were performed on the thenar muscles in 18 ALS patients and 24 healthy controls. Patients were measured at baseline, within 2 weeks, and after 4 and 8 months. Clinical evaluation included Medical Research Council (MRC) scale and the ALS functional rating scale (ALSFRS).

RESULTS: There was a significant positive correlation between MUNE and MUNIX values in ALS patients (r=0.49 at baseline; r=0.56 at 4 months; r=0.56 at 8 months, all p<0.05), but not in healthy controls. After 8 months, both MUNE and MUNIX values of the ALS patients decreased significantly more compared to MRC scale, ALS functional rating scale (ALSFRS) and compound muscle action potential (CMAP) (p<0.05). There was no significant difference in relative decline of MUNIX and HD-MUNE values.

CONCLUSIONS: In ALS patients, MUNIX and HD-MUNE are significantly correlated. MUNIX has an almost equivalent potential in detecting motor neuron loss compared to HD-MUNE.

SIGNIFICANCE: MUNIX could serve as a reliable and sensitive marker for monitoring disease progression in ALS.

Original languageEnglish
Pages (from-to)1644-1649
Number of pages6
JournalClinical Neurophysiology
Volume123
Issue number8
DOIs
Publication statusPublished - Aug 2012
Externally publishedYes

Keywords

  • Action Potentials/physiology
  • Adult
  • Aged
  • Amyotrophic Lateral Sclerosis/pathology
  • Disease Progression
  • Female
  • Humans
  • Longitudinal Studies
  • Male
  • Middle Aged
  • Motor Neurons/pathology
  • Muscle Strength/physiology
  • Muscle, Skeletal/pathology
  • Nerve Degeneration/pathology

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