Brainstem evoked response audiometry/ Auditory brainstem response is an objective neurophysiological test procedure which is used to test the hearing. BERA is a safe, painless, non-invasive procedure which measures the auditory nerve’s response to sounds and measures auditory threshold.
-In BERA patients need to do nothing. patient should lie down calmly or sleep.
– Test is done by placing electrodes on the patient’s head and behind the ears.
-After electrodes placement sound stimuli will be given to ears and the changes in brain electrical activities (EEG) will be measured.
-These changes in brain electrical activities indicate the hearing level.
It is a subjective test of audiological examination. Through behavioral tests it assesses the hearing acuity is normal or impaired.
In this testing procedure pure tone signals are delivered to the ear through air conduction and bone conduction at different frequencies and the patient has to respond to the signals.
Depending on the responses, hearing thresholds are measured and plotted on a graph called audiogram.
This test is used to know the inner ear or cochlear functioning. It measures the otoacoustic emissions from outer hair cells of cochlea. Outer hair cells in the inner ear respond to sound by vibrating and this produces a very quiet sound that echoes back into the middle ear. This sound is the OAE that is measured.
It is mostly done on infants and children for hearing screening.
ASSR is an auditory evoked potential which is used to objectively evaluate the hearing sensitivity. It allows binaural testing, four frequencies in both the ears at the same time (8 simultaneous presentations).
ASSR estimates hearing thresholds across the same range as the ABR, but it offers more spectral information more quickly and can estimate and differentiate hearing within severe to profound hearing loss ranges. This information to detect the significant hearing loss categories is very important to make the decision to choose between the traditional hearing aid or go for a cochlear implantation in children.
Tympanometry is an objective and painless test. It detects the movement and function of the eardrum and middle ear. In this test the audiologist will place a small probe into each ear. The probe which is attached to a small device will push air into your ear and a graph can be seen on a device called a tympanogram. This tympanogram tells the audiologist about the middle ear status.
Here the patient has to sit still and quiet.
Acoustic reflex is the reflexive contraction of the middle ear muscles in response to sound stimulation. It provides information about the middle and inner ear, in addition to the 8th & 7th cranial nerve and brainstem function. The stapedial reflexes can be measured both ipsilateral and contralateral.
The test result shows;
A) The presence or absence of the stapedial reflex.
B) An acoustic reflex threshold
C) Acoustic reflex decay or adaptation(if tested).
A person with hearing loss is rehabilitated with amplification devices, if the ear problems of the patient cannot be treated surgically or medically.
Hearing aid helps in boosting up the signal, so the hearing impaired person can utilize his/her residual hearing to hear the amplified signal. Hearing aids do not restore the hearing.
At first the patient is identified with hearing loss and then refers for hearing aid trial and fitting.
Hearing aids are available in different styles like Behind the ear (BTE), Receiver in the canal (RIC), Completely in the canal (CIC), Pocket model hearing aids etc.
The selection and fitting of hearing aid is based on objective & subjective measures. After purchasing hearing aid the client is counseled regarding the care & maintenance of hearing aid.