In patients with otosclerosis, the Rinne test is used to determine stapes surgery candidacy. The Rinne test is recommended as part of an otological physical exam to detect conductive hearing loss. Anecdotally only two tests, Webber and Rinne, continue to be routinely taught in medical schools and used clinically by otologists and primary care physicians. Historically, up to 20 tuning fork tests were used in the diagnosis of hearing loss.
Placement of the tuning fork tines in parallel as opposed to perpendicular to the EAC results in a higher sound amplitude at the level of the tympanic membrane. ConclusionsĬlinicians vary in their orientation of the tuning fork tines in relation to the EAC when performing the Rinne test. The sound intensity (sound-pressure level) recorded at the tympanic membrane with the 512 Hz tuning fork tines in parallel with as opposed to perpendicular to the EAC was louder by 2.5 dB (95 % CI: 1.35, 3.65 dB p < 0.0001) for the fundamental frequency (512 Hz), and by 4.94 dB (95 % CI: 3.10, 6.78 dB p < 0.0001) and 3.70 dB (95 % CI: 1.62, 5.78 dB p = .001) for the two harmonic (non-fundamental) frequencies (1 and 3.15 kHz), respectively. ResultsĤ7.4 and 44.8 % of 116 survey responders reported placing the fork parallel and perpendicular to the EAC respectively. The amplitudes of the sound delivered to the tympanic membrane with the activated tuning fork tines held in parallel, and perpendicular to, the longitudinal axis of the EAC were measured using a Knowles Electronics Mannequin for Acoustic Research (KEMAR) with the microphone of a sound level meter inserted in the pinna insert. To assess the variability in performing the Rinne test, the Canadian Society of Otolaryngology – Head and Neck Surgery members were surveyed. The present study had two goals: determine if (1) there is clinician variability in tuning fork placement when presenting the air-conduction stimulus during the Rinne test (2) the orientation of the tuning fork tines, parallel versus perpendicular to the EAC, affects the sound amplitude at the ear. Whether the orientation of the tuning fork tines affects the amplitude of the sound signal at the ear in clinical practice has not been previously reported. Guidelines and text-book descriptions of the Rinne test advise orienting the tuning fork tines in parallel with the longitudinal axis of the external auditory canal (EAC), presumably to maximise the amplitude of the air conducted sound signal at the ear.
0 kommentar(er)
