Pure tone audiometry (PTA) is the key hearing test used to identify hearing threshold levels of an individual, enabling determination of the degree, type and configuration of a hearing loss and thus providing a basis for diagnosis and management.
Impedance audiometry is an objective method based on the measurement of the pressure in the middle ear, stapedius reflexes, and tension of the tympanic membrane. It is one of the most common and most accurate methods for testing the middle ear. What is the purpose of Impedance Audiometry
Oto-Acoustic Emission (OAE)
Discovered back in 1978, by D. Kemp, oto-acoustic emissions (OAEs) were not fully explained until a few years later, after the OHC active mechanism had been understood. At least in the mammalian cochlea, OAEs reflect OHC electromotility. OHC contractions/elongations themselves vibrate cochlear fluids and the middle ear conducting mechanism transfers this vibration back to the air of the external auditory canal: there, the emissions can be registered by a microphone.
Brainstem Evoked Response Audiometry (BERA)
- • Brain stem evoked response audiometry (BERA) has been used as an auditory screening procedure in three groups of newborn infants. Group 1 consisted of 220 normal-term infants who were tested within 72 hours of birth; no hearing abnormalities were uncovered (386 ears), and their threshold responses (for clicks) lay between a 10- and 20-dB hearing level (re: adult). Group 2 consisted of 75 newborns who were treated in an intensive care unit for one to 14 weeks; four were found to have severe sensorineural hearing loss (seven ears) at the time of discharge. Group 3 consisted of a group of 325 infants, 1 year or older, who had previously been discharged from the same intensive care unit; of these infants, an additional four showed severe sensorineural hearing loss. All abnormalities that were identified by BERA were subsequently confirmed by conventional audiometric measures. The estimate of an incidence of severe hearing loss in one of 50 infants who required intensive care in the neonatal period calls for careful testing of this population.
Hearing Aid Trial (HAT)
A person with hearing loss which cannot be surgically or medically corrected is rehabilitated with amplification devices. Hearing aids are amplification devices which serve to amplify the acoustic signal to a level which is audible to hearing impaired listener. Hearing aids do not restore hearing ability but they boosts up the signal so that the hearing impaired listener is able to use up his/ her residual hearing to hear the amplified signal. Though initially hearing aid technology was analog based, with the advent of technology, digital technology is implemented in today’s hearing aids.
At NISH, once the patient is identified with hearing loss which is medically or surgically incurable, the patient is referred for hearing aid trial and fitting. Hearing aids are available in different styles including Behind the Ear hearing aids (standard BTE, mini BTE, open fit type BTE),, Receiver In the Ear, In the Canal ,In The Ear, Completely in the Canal ,Pocket level hearing aids etc. Digital hearing aids from world class hearing aid manufacturers are available at NISH at concessional rates.
- A cochlear implant is an electronic medical device that replaces the function of the damaged inner ear. Unlike hearing aids, which make sounds louder, cochlear implants bypass the damaged hair cells of the inner ear (cochlea) to provide sound signals to the brain.