P-NU006. Longitudinal evaluation of fasciculation through ultrasonography in amyotrophic lateral sclerosis

Introduction. Muscle fasciculation in amyotrophic lateral sclerosis (ALS) is typically evaluated through needle electromyography. In recent years, ultrasound has been increasingly used to detect fasciculation particularly as this procedure is non-invasive. We aimed to longitudinally evaluate muscle fasciculation in ALS patients through neuromuscular ultrasound. Methods. ALS patients fulfilling the revised El-Escorial and Awaji criteria presenting to University Malaya Medical Centre were consecutively recruited. Neuromuscular ultrasound was performed at 6-monthly intervals. Two sets of 30-second recordings were obtained from three cervical region muscles (biceps brachii, brachioradialis, first dorsal interosseus) and two lumbosacral region muscles (vastus medialis, tibialis anterior). Fasciculation was considered present when there were ≥ two involuntary contractions. These findings were correlated with disease duration and the revised ALS Functional Rating Scale (ALSFRS-R). Results. A total of 40 patients were recruited. The diagnosis of ALS was definite in 42.5%, probable in 40.0% and possible in 17.5%. The mean onset age was 56.5±8.8 years. Most patients were limb-onset ALS (77.5%). The mean ALSFRS-R was 33.7±9.7 (baseline) and 28.3±11.0 (6 months). At baseline, 17/40 (42.5%) patients had fasciculations in one region, 19/40 (47.5%) in two regions while 4/40 (10.0%) had none. At 6 months, the regions affected remained unchanged in 21 (52.5%) patients. In eight (20.0%) patients, fasciculation was further detected in additional region/s. In five (12.5%) patients, fasciculation could no longer be detected. The disease duration was negatively correlated with the number of muscles with fasciculation detected (R=-0.319 p=0.045 at baseline, R=-0.361 p=0.020 at 6 months). There was, however, no correlation between ALSFRS-R and the number of muscles with fasciculation. Conclusion. Our findings support the role of neuromuscular ultrasound as a diagnostic tool in detecting fasciculation in ALS. However, its role as a prognostic biomarker remains less clear as fasciculation can be less frequently detected with progressive motor neurons loss.