Correlations between MUNIX and adapted multiple point stimulation MUNE methods.

OBJECTIVE

The aim of this study was to evaluate how the motor unit number index (MUNIX) is related to the adapted multiple point stimulation (AMPS) technique.

METHODS

MUNIX and AMPS technique were prospectively performed on thenar muscles in 20 consecutive patients referred to our neurophysiological laboratory with the clinical diagnosis of a possible motoneurone disorder (MND). The clinical and paraclinical assessment confirmed the diagnosis of MND in 13 out of 20 patients, amyotrophic lateral sclerosis (ALS) in 9 (with MND group). In the other 7 patients, there were neither evidence of MND, nor of any peripheral nervous system disease (without MND group).

RESULTS

AMPS and MUNIX data were significantly (p < 0.001) lower in patients with MND than in patients without MND. There was a strong significant positive linear correlation between AMPS and MUNIX values (n = 20; R = 0.83; p < 0.01).

CONCLUSION

Both MUNIX and AMPS methods could serve as a reliable marker to document the motor unit loss.

SIGNIFICANCE: The present paper constitutes one more clue of MUNIX reliability.