How can brain-wave response audiometry test hearing in very young children?

Brain-wave response audiometry, often referred to as auditory brainstem response (ABR) or EEG response audiometry, is a noninvasive method used to test hearing in infants and young children who cannot communicate or cooperate with standard behavioral testing.123

The procedure works by measuring electrical potentials generated by the auditory pathway in response to sound stimuli. The process involves the following steps:23

• Electrode Placement: Electrodes are attached to the child's scalp, typically with one placed behind the ear, to record neural activity.23
• Sound Stimulation: The child is exposed to a series of brief sound stimuli, often while sleeping.23
• Signal Processing: A computer amplifies and averages the minute electrical potentials evoked by these sounds to filter out background noise, such as muscle activity or signals from the cerebral cortex.3
• Interpretation: The resulting recording displays a series of waves representing the neural responses of the auditory pathway in the brainstem. Testers analyze these waveforms to estimate hearing sensitivity, typically by reducing the sound intensity until the evoked response is no longer detectable.23