Introduction
Brainstem Evoked Response Audiometry (BERA), also known as Auditory Brainstem Response (ABR), is a non-invasive and objective test used to evaluate the auditory pathway up to the brainstem. This test is crucial for diagnosing hearing impairments, especially in newborns and individuals who cannot undergo conventional audiometry.
How BERA Works
BERA measures the electrical activity in the auditory nerve and brainstem in response to sound stimuli. Electrodes are placed on the scalp and earlobes to record these responses. When a sound, typically a click or tone burst, is presented through earphones, it travels through the ear canal, eardrum, and middle ear bones to reach the cochlea in the inner ear. The cochlea converts these sound waves into electrical signals, which are then transmitted via the auditory nerve to the brainstem. The electrodes capture the resulting electrical activity, which is displayed as waveforms on a computer screen.
Procedure
Preparation: The patient is asked to lie down comfortably, and electrodes are placed on the scalp and earlobes. For infants, the test is usually conducted while they are asleep.
Stimulation: Sound stimuli, such as clicks or tone bursts, are delivered through earphones. The intensity and frequency of these sounds can be varied.
Recording: The electrodes record the electrical responses generated by the auditory nerve and brainstem. These responses are displayed as waveforms, with each peak representing a specific point along the auditory pathway.
Applications
BERA is used for various diagnostic purposes, including:
Newborn Hearing Screening: Early detection of hearing loss in infants.
Auditory Threshold Estimation: Determining the softest level of sound that can be heard.
Intraoperative Monitoring: Ensuring the integrity of the auditory pathway during surgeries.
Diagnosing Hearing Loss: Identifying the type and degree of hearing loss.
Detecting Lesions: Locating abnormalities in the auditory nerve and brainstem.
Advantages
Non-Invasive: BERA is a safe and painless procedure.
Objective: The test does not rely on patient responses, making it ideal for infants and individuals with communication difficulties.
Accurate: Provides precise information about the auditory pathway.
Conclusion
Brainstem Evoked Response Audiometry (BERA) is a vital tool in the field of audiology. Its ability to objectively assess the auditory pathway makes it indispensable for early detection and diagnosis of hearing impairments. By understanding the procedure and applications of BERA, healthcare professionals can ensure timely and accurate interventions for individuals with hearing loss.
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