The tone decay test or the threshold tone decay test or TTDT is a diagnostic tool for auditory fatigue (temporary loss of hearing after sound exposure). The test provides a measure of the ‘decibels of decay’ i.e. the number of decibels above an individual’s absolute hearing threshold that are required for a tone to be heard for 60 seconds.
In normal individuals, such a tone can be heard continuously for 60 seconds. However, a decay between 15 to 20 decibels indicates cochlear hearing loss while a decay of over 25 decibels indicates damage to the vestibulocochlear nerve.
Getting tested early using the right diagnostic tool and by qualified audiologistshas a tremendous positive impact on your response to treatment.