Unusual Findings in a Bekesy Audiogram

Abstract

Details are presented of a case of acoustic neuroma in which there was a discrepancy between Bekesy sweep-frequency results and those of fixed frequency traces and a tone-decay test. A series of Bekesy fixed frequency traces produced the unexpected findings that frequencies at which adaptation does and does not occur can show bizarre patterns; that the difference between adapting and nonadapting frequencies can be quite small; and that adaptation at a given frequency can vary over a short time. It is suggested that more attention be given to Bekesy fixed frequency tracings when adaptation is not displayed in sweep-frequency tracings.