APPLICATION

Objective Threshold Estimation

Building an objective audiogram in awake adults and older children who cannot give reliable behavioural responses.

What the cortical response shows

  • In cooperative listeners cortical thresholds sit within about 5–10 dB of behavioural thresholds, with a small predictable correction.[6]
0100200300400latency (ms)30 dB above thresholdNear threshold
As stimulus level falls toward threshold the response shrinks and its latency lengthens; the lowest level with a repeatable response estimates threshold.

Why the cortical response here

  • Cortical audiometry uses frequency-specific tonal stimuli without the rate and timing compromises of the ABR, and reflects processing all the way to the cortex.[5]

How it changes management

  • Because it needs an awake, cooperative patient, CERA suits older children and adults; for sleeping infants, ABR and the auditory steady-state response lead, and the methods are often considered together.[7]

TEACHING POINT

Run frequency by frequency, the lowest level with a repeatable cortical response builds an objective audiogram close to the behavioural one — in an awake patient.[6]

Sources for this page are listed on the References page. Browse all applications from the atlas home.