Temporal branch of facial nerve A normative study of nerve conduction

• Published in: Arquivos de Neuro-Psiquiatria
• Main Authors: Silva, Paula Fabiana Sobral da, Lima, Maria Carolina Martins de, Figueiroa, Jose Natal, Lins, Otavio Gomes
• Other Authors: Inst Med Integral Prof Fernando Figueira IMIP, Universidade Federal de Pernambuco (UFPE), Universidade de São Paulo (USP), Escola Pernambucana Med FBV IMIP, Universidade Federal de São Paulo (UNIFESP)
• Format: Article in Journal/Newspaper
• Language: English
• Published: Assoc Arquivos Neuro- Psiquiatria 2010
• Subjects: electrodiagnosis; facial nerve; facial paralysis; neural conduction; Nervo; DML
• Online Access: https://doi.org/10.1590/S0004-282X2010000400026; http://repositorio.unifesp.br/11600/42751

The temporal branch of the facial nerve is particularly vulnerable to traumatic injuries during surgical procedures. It may also be affected in clinical conditions. Electrodiagnostic studies may add additional information about the type and severity of injuries, thus allowing prognostic inferences. The objective of the present study was to develop and standardize an electrophysiological technique to specifically evaluate the temporal branch of the facial nerve. Method: Healthy volunteers (n=115) underwent stimulation of two points along the nerve trajectory, on both sides of the face. The stimulated points were distal (on the temple, over the temporal branch) and proximal (in retro-auricular region). Activities were recorded on the ipsilateral frontalis muscle. The following variables were studied: amplitude (A), distal motor latency (DML) and conduction velocity (NCV). Results: Differences between the sides were not significant. The proposed reference values were: A >= 0.4 mV, DML <3.9 ms and NCV >= 40 m/s. Variation between hemifaces should account for less than 60% for amplitudes and latency, and should be inferior to 20% for conduction velocity. Conclusion: These measurements are an adequate way for proposing normative values for the electrophysiological evaluation of the temporal branch. Inst Med Integral Prof Fernando Figueira IMIP, Recife, PE, Brazil Hosp Clin UFPE, Recife, PE, Brazil Univ Sao Paulo, Sch Med, FMRP, BR-14049 Ribeirao Preto, SP, Brazil Escola Pernambucana Med FBV IMIP, Recife, PE, Brazil Escola Paulista Med, BR-04023 Sao Paulo, Brazil Univ Fed Pernambuco, Dept Neuropsychiat, Recife, PE, Brazil Escola Paulista Med, BR-04023 Sao Paulo, Brazil Web of Science