Defining the relationship between cochlear hearing loss and acoustic reflex thresholds.

In this study several methods of defining the relationship between the magnitude of cochlear hearing loss and the acoustic reflex threshold (ART) levels were examined, with a view to defining the appropriate upper limits of ART that would ease clinical applicability and reduce the false positive rate. The 90th percentile, two standard deviations (SD) from the mean, the regression method and an empirical method based on the scatter plots of the ART at each activator frequency were all applied to the results of 99 patients with cochlear and/or peripheral vestibular pathology. The upper limits of ART defined on the basis of the scatter plots provided the most appropriate upper limits for different ranges of hearing loss, with relatively few false positives. A clinical criterion based on the ART levels at adjacent frequencies is proposed, which further reduces the false positive rate and could also prove effective in the differential diagnosis of cochlear from retro-cochlear lesions.