Contralateral Occlusion Test (COT): Predicting the degree of conductive hearing loss by the effect of external ear canal occlusion

Bedside testing may decrease turnaround time and improve decision making for a quick qualitative assessment of hearing loss. It was designed a bedside test with tuning forks that can allow the quantitative evaluation of hearing loss in the presence of unilateral conductive hearing loss.

COT showed a better association between hearing loss and the lateralization response using the 512 Hz tuning fork (p = 0.001). The sensitivity of the 512 Hz fork in detecting a PTA of at least 35.6 dB was 94.6% and the specificity was 75.0% for a positive predictive value of 89.7% and a negative predictive value of 85.7%, assuming a pretest prevalence of 69.8%.

The overall accuracy of the COT in predicting the degree of unilateral conductive hearing loss was significant. The COT had significant power in one direction: if lateralization to the affected ear occurred, it was almost certain evidence of a moderate or severe conductive hearing loss.