Professor Robert Chen
Editor-in-Chief, Clinical Neurophysiology
Naoum P. Issa, Serdar Aydin, Elena Badillo Goicoechea, Nathan Carberry, Mark A. Garret, Sean Smith, Ali A. Habib, Betty Soliven, Kourosh Rezania
The diagnosis of amyotrophic lateral sclerosis (ALS) requires evidence for both upper motor neuron (UMN) and lower motor neuron (LMN) involvement. While EMG is a well-established diagnostic test to demonstrate LMN involvement, neurophysiological methods to demonstrate UMN involvement are less well established and includes measurement of central motor conduction time and intracortical inhibition using transcranial magnetic stimulation. In this volume of Clinical Neurophysiology, Issa et al. investigated intermuscular coherence (IMC) between lower limb muscles as potential marker of UMN dysfunction in ALS. Coherence between two muscles suggests that they share a common central drive. The authors found that IMC in the 20–40 Hz range was lower in ALS subjects compared to controls. An advantage of this method is that it uses surface EMG and the data can be collected using clinical EMG machines. This technique has the potential to be a method for early diagnosis of ALS.