Simultaneous evoked CMAP recording and sonography reveal a prolonged electromechanical delay in ALS patients

Alterations in electromechanical coupling have been described in patients with amyotrophic lateral sclerosis (ALS) and may contribute to the pathophysiology of the disease. Regardless of this, few measurements of electromechanical delay (EMD) in ALS patients have been published. In this motor nerve conduction study, 28 patients with ALS were examined for changes in electromechanical coupling time compared to healthy individuals using sonoelectromyography, a novel dual-method approach combining simultaneous evoked compound muscle action potential (CMAP) recording following an ENG protocol with Doppler ultrasound. In the examination of four muscles (the abductor digiti minimi muscle, brachioradialis muscle, tibialis anterior muscle, and rectus femoris muscle) ALS patients exhibited prolonged electromechanical delay times. These results demonstrate alterations in the electromechanical properties of muscle fibers and provide further insight into muscle contractility in ALS. The findings support the advancement and wider utilisation of sonoelectromyography as an innovative tool for assessing muscle function and indicate that EMD could be incorporated into diagnostic and disease monitoring protocols in ALS.