24 Mar 2022

Bera Test : Know Everything In Detail

BERA (Brainstem Evoked Response Audiometry) is an objective test used to determine how electrical waves are sent from the eighth cranial nerve to the brainstem in response to click noises delivered through the ear.

Examine the anatomy in greater detail.

Jewett and Williston initially described the Brainstem Evoked Response in 1971. An audiologist is usually the one who performs the test and interprets the results.

When sound reaches the eardrum, it travels through the outer ear canal & stimulates it. The malleus, incus, and stapes, three tiny bone fragments in the eardrum, transmit vibrations to the inner ear. The cochlear, which is involved in listening, and the vestibular portion, which is aimed at maintaining balance, are both located in the inner ear. The 8th cranial nerve, commonly known as the vestibulocochlear nerve, transmits hearing and balancing signals from the inner ear to the brainstem, a key portion of the brain.

BERA is a test that detects any abnormalities in the cranial nerve or brainstem. The test is advised for new-borns who are at significant risk of hearing loss and cannot be tested with standard audiometry.

BERA Test Price in Delhi: What is the test all about?

The cost of the BERA test ranges from INR 1440 and goes up to INR 3000 depending on the place you are doing it from. The BERA test assesses how portions of a child’s nervous system influence or affect his or her hearing. The auditory nerve's response to sounds is measured by the ABR test. It's done if an infant or baby fails the auditory screening test given shortly after birth in the hospital, or if an older child has a suspicion of hearing problems that haven't been confirmed by more traditional hearing tests.

  • The BERA exam is painless and safe.
  • Once the child is asleep or lying motionless, comfortable, and with their eyes shut can the BERA test be conducted.
  • If your baby is under the age of six months, the ABR test can usually be done when he or she is sleeping.
  • If your kid is older than 7, the BERA test can usually be performed while he or she is awake as long as he or she can rest and lay still. The test will take place in an Audiology department sound-treated room.
  • The ABR test is performed under anaesthesia for children aged 6 months to 7 years, which means your child will require medicine to help him or her rest throughout the procedure. 
  • Centres perform ABR tests under anaesthesia. When anaesthesia is required, there are specific eating and drinking guidelines that must be observed in the hours leading up to the procedure. The test will not be completed that day if these regulations are not followed.
  • Your kid's primary care practitioner will need to meet your kid for a medical to sign out a health history form after the tests are done under anaesthesia.
  • The test takes roughly 1 hour to 1 1/2 hours, but owing to recovery time, the full visit will take about 2 hours without anaesthesia and up to four hours if your child requires an aesthetic.

BERA Tests: Why is it done?

It's tough to tell if a child has hearing loss right away. Speech, language, cognitive, social, and emotional issues can all be exacerbated by hearing loss. As a result, it is preferable to conduct a hearing test on children when they are young.

When the sensory neuron can transport audio signals from the eardrum to the cerebral at a specific speed, it is considered healthy hearing. The BERA test can tell you if your nerves are sending sound impulses to your brain and if the sound delivery speed is within acceptable bounds.

The kind of impairment (conducting or input from sensors), degree (hearing threshold), and location of hearing problems (inner ear or other regions) of the child can all be determined during this hearing test.

BERA is also employed in otoneurologico diagnosis in addition to evaluating the hearing threshold. Individuals with single or asymmetric hearing impairment will benefit from this.

BERA Tests: How is it performed?

The electrode that is implanted across the head at various locations to record these waveforms are as follows:

  • Over through the apex of the skull, which is the most conspicuous position at the back of the head, a non-inverting electrode is placed.
  • On each ear lobe or submandibular protrusion, the firm bony rises behind each ear, reverse electrodes.
  • Over the brow, an earthing electrode is placed.
  • The resulting waveforms are amplified using various electrical processes, allowing for easy waveform recording.
  • The waveform's peaks are named Wave I through Wave VII.
  • The electrode that is implanted across the head at various locations to record these waveforms are as follows:
  • Over through the apex of the skull, which is the most conspicuous position at the back of the head, a non-inverting electrode is placed.
  • On every ear lobe or submandibular protrusion, the firm bony rises behind each ear, reverse electrodes.
  • Over the brow, an earthing electrode is placed. The waveform's peaks are named Wave I through Wave VII.
  • The wavelength and the click stimulation are frequently separated by less than 10 milliseconds.
  • Various readings are recorded and annotated in various places and polarities.
  • The waves are recorded and forwarded to be interpreted.
  • The generated waves are amplified using a variety of electrical processes, making waveform recording simple.

Getting Ready for the BERA Exam

The BERA test price is not very high but the preparation before the test must be done with utmost care. Here are the tips below:

  • Oil-free hair is required. Before the test, the person being tested is encouraged to take a shampoo bath.
  • The BERA technique still requires a lot of lying. As a result, the person or new-born may be given a mild sedative to put them to bed during the surgery.

What are the BERA Test's Indications?

The BERA technique is suggested:

  • To locate the source of the hearing loss. From the cranial nerve to the brainstem, the test detects abnormalities.
  • As an auditory diagnostic test in hyperactive, mentally ill, or other youngsters who might not respond to traditional audiometry.
  • Hearing loss that is more noticeable in one ear than another is known as asymmetric hearing loss.
  • As a hearing test for new-borns at high risk of hearing loss, such as those with a family background of congenital hearing loss.

-Hyperbilirubinemia (excess bilirubin)

-Head deformities or abnormalities 

-Head injuries 

-Head deformities or abnormalities 

  • Nervous system anomalies and acoustic neuroma, a mammary tumour of the eighth cranial nerve, are suspected.

Interpreting BERA Test Results

The brainstem produces audio evoked potential signals that are recorded as waves with peaks and troughs. Wave I, Wave II, and so on are positive potentials recorded from the sensor at the vertex and are labelled as wave I, Wave II, and so on until wave VII.