Contralateral Occlusion Test: The effect of external ear canal occlusion on hearing thresholds

Introduction and goals Bedside testing with tuning forks may decrease turnaround time and improve decision making for a quick qualitative assessment of hearing loss. The purpose of this study was to quantify the effects of ear canal occlusion on hearing, in order to decide which tuning fork frequency is more appropriate to use for quantifying hearing loss with the Contralateral Occlusion Test. Methods Twenty normal-hearing adults (forty ears) underwent sound field pure tone audiometry with and without ear canal occlusion. Each ear was tested with the standard frequencies. The contralateral ear was suppressed with by masking. Ear occlusion was performed by two examiners. Results Participants aged between 21 and 30 years (25.6 ± 3.03 years) showed an increase in hearing thresholds with increasing frequencies from 19.94 dB (250 Hz) to 39.25 dB (2000 Hz). The threshold difference between occluded and unoccluded conditions was statistically significant and increased from 10.69 dB (250 Hz) to 32.12 dB (2000 Hz). There were no statistically significant differences according to gender or between the examiners. Conclusion The occlusion effect increased the hearing thresholds and became more evident with higher frequencies. The occlusion method as performed demonstrated reproducibility. In the Contralateral Occlusion Test, 256 Hz or 512 Hz tuning forks should be used for diagnosis of mild hearing loss, and a 2048 Hz tuning fork should be used for moderate hearing loss. © 2017 Elsevier España, S.L.U. and Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello