Role of neuromuscular ultrasound in the evaluation of amyotrophic lateral sclerosis

Abstract Background Amyotrophic lateral sclerosis (ALS) is the commonest presentation of adult motor neuron diseases. Diagnosis can be difficult due to the heterogenous clinical presentation of the disease. Most neuromuscular ultrasound studies focus on imaging the same structures belonging to one or two segments of the neuroaxis. Facial nerve ultrasound has not been well investigated in ALS. This work aims at evaluating the role of neuromuscular ultrasound in diagnosing and monitoring ALS. Sixteen adult male patients diagnosed with clinically definite ALS, as well as twenty age and gender matched control subjects, were recruited. Each patient was given a score according to the ALS functional rating scale-revised edition. Electrophysiological studies and high-resolution ultrasound were performed on the Facial, Median, Ulnar, Tibial and Common peroneal nerves, as well as Masseter, Sternocleidomastoid, Biceps brachii/Brachialis complex, First Dorsal Interosseus, Vastus Intermedius/Rectus Femoris complex, and Tibialis anterior muscles. Results ALS patients demonstrated significantly decreased Facial nerve diameter, Tibial nerve cross sectional area, and thickness of Biceps/Brachialis complex, Tibialis anterior, First Dorsal Interosseus, and Vastus intermedius/Rectus femoris complex. Tibialis anterior thickness and Facial nerve diameter showed the highest sensitivity and specificity in monitoring clinical progression in ALS. Conclusion Neuromuscular ultrasound is a reliable objective tool in diagnosing and monitoring ALS.