Prognostic value of electroneurography using the midline method for predicting the development of synkinesis after peripheral facial palsy

Aishi Okazaki; Haruki Nakano; Shin-Ichi Haginomori; Yusuke Ayani; Yuko Inaka; Akiko Ozaki; Yusuke Kikuoka; Takaki Inui; Ayumi Nakazawa; Shin-Ichi Wada; Ryo Kawata

doi:10.1016/j.anl.2024.02.005

Prognostic value of electroneurography using the midline method for predicting the development of synkinesis after peripheral facial palsy

Auris Nasus Larynx. 2024 Mar 28;51(3):599-604. doi: 10.1016/j.anl.2024.02.005. Online ahead of print.

Authors

Affiliations

¹ Department of Central Clinical Laboratory, Osaka Medical and Pharmaceutical University Hospital, Takatsuki, Japan. Electronic address: aishi.okazaki@ompu.ac.jp.
² Department of Physical and Rehabilitation Medicine, Division of Comprehensive Medicine, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.
³ Department of Otolaryngology - Head and Neck Surgery, Osaka Medical and Pharmaceutical University, Takatsuki, Japan.
⁴ Department of Central Clinical Laboratory, Osaka Medical and Pharmaceutical University Hospital, Takatsuki, Japan.
⁵ Laboratory of Medical Technology III, Faculty of Nutrition, Kobe Gakuin University, Kobe, Japan.

PMID: 38552423
DOI: 10.1016/j.anl.2024.02.005

Abstract

Objective: The prognostic value of electroneurography (ENoG) for predicting the incidence of synkinesis is reportedly about 40 % using the formal standard method (ENoG-SM). However, the prognostic value of ENoG using the newly developed midline method (ENoG-MM) has not been determined. The aim of this study was to demonstrate the optimal prognostic value and advantages of ENoG-MM for predicting the incidence of synkinesis.

Methods: Participants were 573 patients treated for peripheral facial palsy including Bell's palsy or Ramsay Hunt syndrome. We investigated the clinical presence of any oral-ocular or ocular-oral synkinesis from the medical records. ENoG-MM and ENoG-SM were performed 10-14 days after symptom onset. In ENoG-MM, compound muscle action potentials were recorded by placing the anode on the mental protuberance and the cathode on the philtrum. In ENoG-SM, electrodes were placed on the nasolabial fold. Synkinesis was clinically assessed at the end of follow-up or at >1 year after onset. The sensitivity and specificity of ENoG values for predicting the incidence of synkinesis were compared between ENoG-MM and ENoG-SM at every 5 % around 40 % (range, 30-50 %).

Results: At every 5 % of ENoG values around 40 %, ENoG-MM provided higher sensitivity and lower specificity for predicting the incidence of synkinesis compared with ENoG-SM. In particular, when the cut-off value was set at 45 %, sensitivity was 100 % and 95.3 % with ENoG-MM and ENoG-SM, respectively.

Conclusion: In peripheral facial palsy, ENoG-MM offered higher sensitivity than ENoG-SM for predicting synkinesis. ENoG-MM is useful for screening patients at risk of developing synkinesis. In clinical practice, an ENoG-MM cut-off value of 45 % must be the optimal prognostic value because of the 100 % sensitivity.

Keywords: Bell's palsy; Electroneurography; Facial paralysis; Ramsay Hunt syndrome; Synkinesis.