Evaluation of eardrum laser doppler interferometry as a diagnostic tool.
OBJECTIVE
Laser Doppler interferometry (LDI) of the eardrum allows noncontact optical analysis of its vibrations in response to sound. Although LDI has been widely used in research, it has not yet been introduced into clinical practice as an adjunctive test for otological workup. The aim of this study was to evaluate LDI as a diagnostic tool in the clinical sphere.


METHODS
Prospective.


METHODS
A measurement system was developed based on a commercially available scanning He-Ne laser Doppler interferometer. The study included 129 eardrums of 79 subjects that were divided into 3 groups: 1) normal subjects and 2) patients with sensorineural and 3) conductive hearing loss (HL). All the patients suffering from conductive HL underwent ossiculoplasty, which allowed confirmation of the final diagnosis, and patients were assigned accordingly to the subgroups malleus fixation, incus luxation, and stapes fixation.


RESULTS
The modified LDI system allowed bilateral evaluation of a subject within 30 minutes. No significant difference between normal subjects and patients having sensorineural HL were found. However, it was possible to distinguish between normal subjects and patients with conductive HL. Furthermore, the system had the ability to differentiate between various middle ear diseases. These groups differed statistically significantly in terms of manubrium vibration amplitude and resonance frequency. In malleus fixation significant differences in tympanic membrane movement patterns were found.


CONCLUSIONS
Our LDI is applicable in clinical otological practice and serves as a valuable addition to the routine audiological investigations for preoperative evaluation of the mobility and integrity of the ossicular chain.
Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital of Zürich, Frauenklinikstrasse, CH-8091 Zürich, Switzerland. alex.huber@orl.usz.ch
A M
AM
Huber
C
C
Schwab
T
T
Linder
S J
SJ
Stoeckli
M
M
Ferrazzini
N
N
Dillier
U
U
Fisch
D000328:Adult; D000368:Aged; D005260:Female; D006314:Hearing Loss, Conductive / Q000175:diagnosis* / Q000503:physiopathology; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D007368:Interferometry; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012016:Reference Values; D012680:Sensitivity and Specificity; D014432:Tympanic Membrane / Q000503:physiopathology*