In this study, the deposits of basophilic material on the cupula of the semicircular canals in temporal bones from patients who had aminoglycoside administration within six months prior to death were compared with normal temporal bones. Subjects were divided into two groups. Group I included 24 normal control temporal bones age-matched to group II patients. Group II consisted of 23 temporal bones that had received aminoglycosides within six months prior to death. All temporal bones were examined under light microscopy.

One (4.2 per cent) of 24 temporal bones in group I (normal) showed basophilic deposits. In group II, deposits were observed in 8 (34.8 per cent) of 23 temporal bones. The prevalence of basophilic deposits in group II was significantly higher than group I.

This study demonstrates that within six months after aminoglycoside administration there is an increased prevalence of basophilic deposits on the surface of the cupula. Such changes may be related to the benign paroxysmal positional vertigo (BPPV) seen in some patients who have had aminoglycoside administration.