Relation between Frequency of Synkinesis and Electrodiagnositic Findings after Facial Palsy

J Korean Assoc EMG Electrodiagn Med 2007;9(1):8-11.
Published online May 10, 2007.

Abstract

Objectives: The frequency of synkinesis after facial palsy has not been clearly defined. We investigated the development of synkinesis after facial palsy and its relationship to electrodiagnostic findings. Methods: In 43 patients with facial palsy, we performed side-to-side comparison of CMAP by placing the recording electrodes over the nasalis muscle and facial nerve stimulation at stylomastoid fossa to evaluate the degree of axonal loss. In follow up study, we observed whether the synkinetic spread response was found or not during stimulation of supraorbital notch and investigated the relationship between axonal loss and frequency of synkinesis. Results: Electrophysiologically, 26 (60.5%) out of 43 patients showed synkinesis. All of them had more than 40% axonal loss, and had clinical synkinesis except one. It took 144±69 from the onset of facial palsy to the development of synkinesis. With severer axonal loss, the frequency of synkinesis increased (p<0.05). The group of patients who developed synkinesis showed more axonal injury than the group of patients who did not (p<0.05). Conclusion: The severer the axonal loss, the more frequent the development of synkinesis. Therefore, we need to help patients with severe axonal loss prevent the development of synkinesis.

Key Words: Synkinesis, Facial palsy