Clinical Application of Intensity Difference Limen

Abstract

SISI tests were administered at various sound pressure levels in normal and pathologic subjects. When the inner ear receives an audible signal of 60 dB SFL or greater, a positive SISI score will occur in both normal and sensorineural hearing losses except in those with abnormal Actaptation. A negative SISI score in the absence of a conductive barrier occurs only in abnormally Actapting ears and is probably indicative of supra-threshold Actaptation. Our data indicate that recruiting ears and normal ears perceive intensity increments of equal size at equivalent SPL. In abnormally Actapting ears, as Bekesy separation increases, the increment tends to become larger than normal. Continuous tone Bekesy thresholds measured at the bottom of the first spike increase directly with starting intensity and inversely with attenuation rate. Variations of the SISI test and Békésy audiometry are proposed.