Fasciculation in limbs serves as the predictor of ALS progression: an ultrasound study

To explore the predictive effects of fasciculation by ultrasound in amyotrophic lateral sclerosis (ALS) progression.

Sporadic ALS patients were consecutively recruited and followed up 3 to 6 months after the initial visit. Muscle ultrasound examination was conducted at the baseline to detect the severity score of fasciculations on bilateral elbow flexor and extensor, ankle dorsiflexor and plantar flexor of each patient, the sum of which was defined as the total fasciculation score. Baseline and follow-up ALS functional research scale-revised (ALSFRS-R) score and muscle strength were collected. The progression of ALS was reflected by the decline rate of ALSFRS-R score and proportion of muscles with decreased strength.

Among 33 ALS patients who completed the follow-up, the total fasciculation score was positively correlated with the ALSFRS-R progression rate (rho = 0.029, p < 0.001). Patients with low levels of the total fasciculation score had a significantly lower risk of rapid ALSFRS-R progression during follow-up compared to those with high levels of the total fasciculation score (HR 0.132, 95%CI 0.037-0.476). The frequencies of decline in muscle strength at the follow up were 76.32% and 16.54% among muscles with and without high-grade fasciculation (p < 0.001) after exclusion of muscles with 0-1 the medical research council (MRC) levels of strength at the baseline.

The severity of fasciculations was correlated with the rate of decrease in ALSFRS-R score and the decline in muscle strength, which might be used as a biological marker to predict the progression rate of ALS for prognostic judgment or clinical trial grouping.