On the etiology of synkinesis following facial nerve palsy

Abstract

The authors report on patients with degeneration potentials in electromyography in at least one mimic muscle during the course of their Bell's palsy. In some of these patients, who had synkinesis moving certain mimic muscles, analysis of the distribution of degeneration potentials showed no such potentials in these (but in other) muscles during the course of their paralysis. These findings point to the possibility that not only misdirected axons but also more centrally located structures of the CNS may be involved in the genesis of synkinesis following Bell's palsy.

Electron Microscopical Evidence of Synaptic Reorganization in the Contralateral Motor Cortex of Adult Rats following Facial Nerve Lesion

“…From the clinical point of view it is not only of interest whether synaptic reorganization induces transient or per manent functional changes to explain the above-men tioned clinical phenomena [1][2][3], It should also be an aspect of further investigations whether these changes may be influenced by certain training methods or phar macological therapy e.g. by corticosteroids.…”

“…Brudny et al [2] observed better results of mimic expression after hypoglossal-facial nerve anasto mosis using EMG feedback training during the reinnerva tion period. Laskawi et al [3] found synkinesis in patients that showed no degeneration potentials in the EMG dur ing Bell's palsy. All these clinical phenomena can hardly be explained by an altered mode of peripheral axonal sprouting after nerve lesion.…”