Hilger facial nerve stimulator: a 25-year update

Area of Science:

• Otolaryngology
• Neurology
• Clinical Electrophysiology

Background:

• Percutaneous nerve excitability testing with the Hilger facial nerve stimulator has been a standard for 25 years.
• It remains the most common method for prognostication in facial nerve disorders due to its reliability, ease of use, and low cost.

Purpose of the Study:

• To evaluate the prognostic value of facial nerve excitability testing.
• To identify factors influencing nerve stimulation values and recovery.
• To assess intertester reliability of the test.

Main Methods:

• Analysis of 10,243 nerve excitability tests from 865 patients (1966-1974).
• Application of a multiple regression model to assess the impact of age, sex, race, comorbidities (diabetes, hypertension), paralysis severity, herpes zoster diagnosis, testing year, and recovery on stimulation values.
• Prospective evaluation of 25 patients with residual paralysis by two otolaryngologists for intertester reliability.

Main Results:

• Established statistical reliability of the nerve excitability test.
• Identified key demographic and clinical factors affecting nerve stimulation values.
• Provided a table of interpretive results and practical "tips and traps" for clinicians.
• Demonstrated acceptable intertester reliability in a prospective cohort.

Conclusions:

• Facial nerve excitability testing is a statistically reliable and clinically valuable tool for predicting outcomes in facial nerve disorders.
• Understanding influencing factors enhances the interpretation of test results.
• The test offers practical guidance for practitioners managing facial paralysis.