The development of synkinesis after facial nerve paralysis

in this study, the development of clinical synkinesis after facial nerve pa ralysis (FP) and its relationship to electrophysiological findings were inv estigated. Thirty-four patients who were examined within the first 5 days a fter onset of FP and who could also be followed up for at least 4 months we re included in the study. Electrophysiological investigations consisted of: (1) recording of the direct responses by facial nerve stimulation at the s tylomastoid fossa; (2) recording of the 'synkinetic spread' of the supraorb ital nerve reflex to the lower facial muscles; (3) recording of the 'latera l spread responses' by stimulating the mandible and zygomatic branches of t he facial nerve. Clinical synkinesis developed in 14 of 18 patients (78%) w ith a direct response ratio (DRr) of less than 40%, Among the 16 patients w ith a DRr of 40% or more, synkinesis was observed in 3 cases (18.7%) only. The DRr provided reliable information concerning the development of synkine sis, Forty percent seemed to be a reasonable limit to distinguish the high- risk group for the development of clinical synkinesis. Copyright (C) 2000 S . Karger AG, Basel.