Auditory Brainstem Response

 

                                                           Auditory Brainstem Response 

When sound enters the ear:

It stimulates the cochlea.

The signal is transmitted via the auditory (VIII cranial) nerve.

The signal then passes through several brainstem nuclei, including:

• Cochlear nucleus
• Superior olivary complex
• Lateral lemniscus
• Inferior colliculus

Each of these generates characteristic waveforms in the ABR test.

ABR typically produces 7 waves (labeled I to VII) within the first 10 milliseconds after the sound stimulus. Clinically, waves I, III, and V are most important:

Wave	Generator Site
I	Distal auditory nerve (near cochlea)
II	Proximal auditory nerve
III	Cochlear nucleus
IV	Superior olivary complex
V	Lateral lemniscus and inferior colliculus
VI & VII	Midbrain (less commonly used clinically)

Uses Of Auditory Brainstem Response

Clinical Uses

Newborn hearing screening

Diagnosing sensorineural hearing loss

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