Abstract
Objectives:
Evaluate the reability of laser doppler vibrometry (LDV) of the tympanic membrane (TM) and ear canal reflectance (ECR) measurements in the differential diagnosis of partial and complete ossicular discontinuity (OD).
Methods:
Patients, with surgically confirmed partial or complete OD and an intact TM, were recruited from the Otology clinic. Pre-operative possible diagnosis were made by otoscopic examination, audiometry, LDV and ECR. Audiometry, LDV and ECR data in each of the two OD subgroups were evaluated in order to determine their use in differential diagnosis.
Results:
44 patients with surgically confirmed OD with intact TM (27 complete, 17 partial) were included in this study. Audiometry was performed in all cases. There were statistically significant differences in air-bone gap (ABG) between the two subgroups below 1 kHz. LDV was performed in 29 (16 complete, 13 partial). An increase in LDV magnitude and a decrease in phase angle below 1 kHz were greater in the complete OD subgroup, but not significantly. ECR was performed in 11 (5 complete, 6 partial). ECR near 1 kHz was lower than the normal in both OD subgroups and the difference between the two subgroups was significant.
Conclusions:
A difference between the means of ECR measurements suggests a possible clinical utility. On the other hand, subgroup difference in LDV magnitude and phase angle were not significant. A combination of LDV, ECR and audiometry may help differentiate the two conditions. More patient data will enable better evaluation of the diagnostic significance of the observed differences.
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