Original Paper

Blink Reflex R2 Recovery Curves in Patients with Facial Palsy within Ten Days after Onset
Naoki Toda^a, Katsuhiko Nakamura^b, Noriaki Takeda<sup>b

a</sup>Department of Otolaryngology, Kochi National Hospital, Kochi, and
^bDepartment of Otolaryngology, University of Tokushima School of Medicine, Tokushima, Japan

Address of Corresponding Author

ORL 2005;67:16-22 (DOI: 10.1159/000083009)

  Key Words

• Facial palsy
• Adaptive response
• Blink reflex
• Recovery curve

  Abstract

The purpose of this study was to investigate the acute changes in blink reflex responses in patients with facial palsy. We used the blink reflex R2 recovery curves as an index of the excitability of the blink reflex neural circuit and evaluated the excitability of the blink reflex within 10 days after onset. Twelve patients with peripheral facial palsy were selected on condition that the degree of facial palsy was so mild that R2 responses of the blink reflex were measurable on the affected side, and they were compared with 12 healthy volunteers. Conditioning and test electrical stimuli were delivered on the affected side of the supraorbital nerve. Ipsilateral R2 response (iR2) of the blink reflex in patients was significantly enhanced at interstimulus intervals (ISIs) between conditioning and test stimuli from 100 to 1,000 ms, in comparison with the control subjects. These findings suggested hyperexcitability of the blink reflex neural circuit in patients with facial palsy. In addition to iR2, contralateral R2 response (cR2) in the patients was also significantly increased at ISIs of 100-1,000 ms to the same extent as the enhancement of iR2. All these findings suggested that the hyperexcitable changes developed in a common pathway of iR2 and cR2, but not in the ipsilateral facial motor neurons. It is suggested that the hyperexcitability of the neural circuit of the blink reflex during an acute period of facial palsy is an adaptive response to compensate for impaired facial motor function.

Copyright © 2005 S. Karger AG, Basel

  Author Contacts

Dr. Naoki Toda
Department of Otolaryngology, Kochi National Hospital
1-2-25 Asakura nishi
Kochi 780-8077 (Japan)
Tel. +81 88 844 3111, Fax +81 88 843 6385, E-Mail mutimaro@d2.dion.ne.jp

  Article Information

Received: November 19, 2003
Accepted after revision: September 9, 2004
Published online: January 4, 2005
Number of Print Pages : 7
Number of Figures : 6, Number of Tables : 1, Number of References : 16