Muscle changes in amyotrophic lateral sclerosis: a longitudinal ultrasonography study

Abstract

Objective: We performed a longitudinal study to assess structural muscle changes in amyotrophic lateral sclerosis (ALS) using ultrasonography.

Methods: During a follow-up of 6 months, ultrasonography parameters (muscle thickness, echo intensity and fasciculations) were obtained from 6 muscle groups in 31 ALS patients, together with strength and scores on the revised ALS functional rating scale (ALSFRS-r).

Results: At baseline, we found an increased echo intensity and decreased thickness, and these parameters correlated with lower strength. Moreover, ultrasound abnormalities were also detected in muscles with preserved strength. Longitudinal changes in echo intensity, muscle thickness and fasciculations showed large variations between patients. Rates of change in ultrasound parameters did not correlate with changes in ALSFRS-r or strength.

Conclusion: In patients with ALS ultrasound abnormalities can be found in muscles with preserved strength. The pattern of ultrasonographic muscle changes in ALS is highly variable and shows no evident correlation with functional measures.

Significance: Ultrasonography is not suitable to monitor disease progression in ALS.