P-NU002. Muscle ultrasound is a highly sensitive non-invasive tool to detect fasciculations in limbs, tongue and paraspinal muscles in amyotrophic lateral sclerosis

Abstract

Introduction . Fasciculations are characteristic feature of Amyotrophic Lateral Sclerosis (ALS) and their identification by Muscle Ultrasound (MUS) is an important non-invasive tool and allows studying the major bulk and more inaccessible muscles. This could potentially replace painful Electromyography (EMG) procedure to identify fasciculations. Our aim is to utilize MUS to identify and also detect fasciculations in unaffected muscles in early stages of ALS and correlate with EMG findings. Methods . In 30 cases (7 bulbar and 23 limb onset) with suspected ALS, we performed EMG in 3 muscles (biceps brachii, quadriceps and thoracic paraspinal) and MUS in 9 muscles (biceps, triceps, deltoid, abductor digiti minimi, quadriceps, hamstrings, tibialis anterior, thoracic paraspinal and tongue). MUS was performed using linear transducer (3-13 MHz, Esaote Mylab Gamma Scanner). Fasciculations were observed in each muscle for one minute. Frequency of fasciculations detected by MUS was compared with EMG findings in same muscles. Results . The M:F ratio was 4:1, age of onset was 50.1±12.8 years, age of presentation was 50.9±12.9 years. Duration of illness was 1.21±1.08 years. Of the total muscles studied, 176 muscles showed wasting while 334 were normal. Out of 284 muscles without clinical fasciculations, 206 (72.5%) showed fasciculations on MUS. Of 90 muscles examined by EMG, 20 (40.8%) of 49 muscles without clinical fasciculations showed fasciculations. Out of 23 pure limb onset cases, 16 cases showed extrinsic tongue muscle fasciculations on MUS. Fasciculations as detected by MUS vs. EMG: biceps brachii (90% vs 76.6%), quadriceps (80% vs 50%) and thoracic paraspinal (66.6% vs 40%) Conclusion . MUS is a promising tool in diagnosis of ALS. MUS is more sensitive in detecting fasciculations compared to EMG, can substitute it as it is noninvasive, safer, easily accessible, can access larger muscle areas in shorter examination time. Further, the test can be repeated for any longitudinal/sequential assessments.