Facial nerve vulnerability in spinal muscular atrophy and motor unit number index (MUNIX) of the orbicularis oculi muscle.

Our results provide neurophysiological evidence of facial nerve and muscle involvement in patients with SMA. CMAP of the facial nerve and MUNIX of orbicularis oculi showed high accuracy in discriminating between the various subtypes of SMA and in quantifying the motor unit loss of the facial nerve. This article is protected by copyright. All rights reserved.