Rinne test: does the tuning fork position affect the sound amplitude at the ear?

Area of Science:

• Audiology
• Otolaryngology
• Medical Acoustics

Background:

• Standard guidelines for the Rinne test recommend parallel tuning fork orientation along the external auditory canal (EAC).
• This is presumed to maximize air-conducted sound amplitude.
• The actual impact of tuning fork orientation on sound amplitude in clinical practice remains uninvestigated.

Purpose of the Study:

• To investigate clinician variability in tuning fork placement during the Rinne test.
• To determine if tuning fork tine orientation (parallel vs. perpendicular to the EAC) affects sound amplitude at the ear.

Main Methods:

• A survey of Canadian Society of Otolaryngology - Head and Neck Surgery members assessed variability in Rinne test performance.
• Sound amplitudes were measured using a KEMAR mannequin with a sound level meter microphone in the ear canal.
• Measurements were taken with tuning fork tines positioned parallel and perpendicular to the EAC.

Main Results:

• Survey results showed significant clinician variability, with 47.4% placing the fork parallel and 44.8% perpendicular to the EAC.
• Parallel orientation of a 512 Hz tuning fork resulted in significantly higher sound pressure levels at the tympanic membrane compared to perpendicular.
• Harmonic frequencies also showed increased amplitude with parallel orientation for both 512 Hz and 256 Hz tuning forks.

Conclusions:

• Clinician practices for tuning fork orientation in the Rinne test are inconsistent.
• Positioning tuning fork tines parallel to the EAC demonstrably increases sound amplitude at the tympanic membrane.