Tone Decay Test
A diagnostic procedure that assesses the ability to sustain perception of a continuous tone at threshold, with rapid decay suggesting retrocochlear pathology.
Full Definition
The tone decay test, also called the auditory adaptation test, presents a continuous pure tone at or slightly above the patient's threshold to measure how long they can perceive it before the sound appears to fade. Significant tone decay—typically defined as a threshold shift of 30 dB or more within 60 seconds—is associated with retrocochlear conditions such as acoustic neuroma. Various protocols exist, including the Carhart, Rosenberg, and Green procedures, each differing in stimulus intensity increments and timing. Editors should specify which protocol was used and must not conflate tone decay with threshold shift related to noise exposure. This test is now largely supplemented by ABR and imaging but remains referenced in differential diagnosis literature.
Usage
Usage note: Specify the procedural variant (Carhart, Rosenberg, or Green) in clinical documents; failure to do so is a common editorial omission.
In Context
- "The tone decay test revealed a 35 dB shift within 45 seconds at 2,000 Hz, raising suspicion for a retrocochlear lesion." — Neurological audiology report
- "Editors should verify that the specific tone decay protocol is named, as results are not interchangeable across variants." — Audiology report style guide