Brainstem Evoked Response Auditory/Auditory Brainstem Response Test

Brainstem Evoked Response Auditory (BERA), which is also known as Auditory Brain Response (ABR) is an objective test that’s used to estimate hearing sensitivity and detect neurological abnormalities.

This electro-physiological and neurological screening procedure of auditory brainstem function measures the electrical brain waves that are stimulated by clicks, at various levels of auditory system to examine the brainstem’s central auditory pathways.BERA or ABR is the most common application of evoked auditory responses and is sometimes also referred to as Auditory Evoked Potential (AEP).

These tests are used mostly used with children who have a difficult time with conventional hearing screenings and behavioural methods.

Most common indications for BERA/ABR

1. Children with hearing impairment
2. Nervous system disorders
3. Acoustic Neuroma
4. Malingering patients
5. To examine one’s neurological functions
6. Central Pontine Myelinolysis

How does the audiology procedure work?

Such audiology screenings and procedures typically involve a click or a tone stimulus. This stimulus generates a response from the cochlea, the auditory portion of the inner ear, and is transmitted inside via a transducer.

These signals then travel along the auditory pathway to the inferior colliculus. As the clicks are delivered, the electrical waves generated at the brain stem are recorded by electrodes.

The general electrode configuration used in ABR/BERA involves an inverting electrode placed on the earlobe, non-inverting electrode placed over the vertex and an earthing electrode (for preamplifier functioning) over the forehead.

The BERA/ABR test detects different waveforms arising from:

• Auditory Nerve
• Cochlear Nerve
• Superior Olivary Nucleus
• Inferior Colliculus
• Lateral Lemniscus
• Medical Geniculate Nucleus