- Audiological Tests
- Hearing loss
- Cochlear Implant Candidacy and Rehabilitation
- Hearing Aid
- Speech Therapy
Pure Tone Audiometry :
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. Thus, providing the basis for diagnosis and management. PTA is a subjective, behavioural measurement of hearing threshold, as it relies on patient response to pure tone stimuli. Therefore, PTA is used on adults and children old enough to cooperate with the test procedure.
ABR audiometry :
An electronic measure of auditory function using responses produced by the auditory nerve and the brainstem. Also called brainstem evoked response audiometry
Speech Audiometry :
Speech Audiometry is a technique where standardized a sample of language are presented
through a calibrated system in order to measure some aspects of hearing abilities. The
standard (standardized) materials can be through live wire or recorded system.
Otoacoustic emissions are sounds made by our inner ear as it works to extract the information from sound to pass on to the brain. These biological sounds are a natural by-product of this energetic biological process and their existence provides us with a valuable ‘window’ on the mechanism of hearing, allowing us to detect the first signs of deafness - even in newborn babies. Sounds made by healthy ears are quite small - quieter than a whisper and usually less than 30dBSPL. They arrive in the ear canal because the middle ear receives vibrations from deep inside the cochlea. This causes the eardrum to vibrate the air in the ear canal creating the sounds that we can record. To record otoacoustic emissions, or ‘OAEs’, a ‘probe’ is inserted in the ear canal. The probe closes the ear canal, keeping the OAEs in and any noise out. The probe both stimulates the ear with precisely defined sounds and records the sounds made by the ear via a tiny microphone.
Hearing loss can be broadly classified into 3 types.
- Conductive hearing loss : Hearing Loss which occour due to pathology in middle prder ear. It is medically treatable and not a permanent loss.
- Sensorineural Hearing Loss : In sensorineural hearing loss, the damage lies in the inner ear, the acoustic nerve, or both. This is permanent loss.
- Mixed Hearing loss : Hearing Loss which is partly conductive.
- What Next: When a child or adult is identified hearing sensorineural hearing loss the next step is to provide an amplification or hearing aid derived to them.
Cochlear implantation is a life-changing event to many patients with hearing losses that are not effectively managed with well-fit hearing aids. With the experience most implant users are able to understand spoken speech in the everyday world. Some patients are able to enjoy music and/or hold conversations on the phone.
A cochlear implant is a device that provides sound perception through direct electrical stimulation of the hearing nerve, bypassing the inner ear . A cochlear implant is comprised of two parts -- and internal device and an external device. The internal device is surgically implanted under the skin and is comprised of a receiver, a magnet, and a bundle of fine wires, the electrode array. The external device called the sound processor The sound processor analyzes incoming sounds from the microphone and converts those sounds into patterns of electrical current. The current is carried along the cable and delivered across the skin by radio wave transmission to a receiver implanted under skin. The receiver carries the current to the electrode array, which has been implanted into the cochlea, the portion of the inner ear that contains hearing nerve fibers. The current stimulates fibers of the auditory nerve and results in the perception of sound.
- • Severe to profound hearing loss bilaterally
- • Those who have limited benefit from hearing aids.
- • Little or no benefit from hearing aids, defined as speech recognition scores of less than 50% on sentence level testing in the ear to be implanted and less than 60% in the non-implanted ear or in the binaural condition.
- • Severe to profound loss bilaterally>
- • Little or no benefit amplification
- • Lack of progress in the development of auditory skills.
- • High motivation and realistic expectations regarding benefit from the child and parents.
- • Profound sensorineural hearing loss bilaterally.
- • Lack of progress in development of auditory skills with hearing aid(s) or other amplification.
- • High motivation and realistic expectations from family.
- • Other medical conditions, if present, do not interfere with cochlear implant procedure.
There are many types of hearing aids (also known as hearing instruments), which vary in size, power and circuitry. Among the different sizes and models are:
Behind the ear aids (BTE):
BTE aids consist of a case, a tube and an earmold. The case is small and made of plastic. Generally, the case sits behind the pinna (ear) with the tube coming down the front into the earmold. The case contains the amplification system. The sound is routed from the hearing aid case to the earmold via the tube.
BTEs can be used for mild to profound hearing loss. Due to the electrical components being located outside the ear, the chance of moisture and earwax damaging the components is reduced.
In the ear aids (ITE):
These devices fit in the outer ear bowl (called the concha); . ITE hearing aids are custom made to fit each individual's ear. They can be used in mild to some severe hearing losses.
Receiver In the Canal/Ear (RIC/RITE):
With a RITE hearing aid, the speaker is right in the ear canal and the amplified output of the hearing aid does not need to be pushed through an acoustic tube to get there, and is therefore free of this distortion. Secondly, RITE hearing aids can typically be made with a very small part behind-the-ear and the wire connecting the hearing aid and the speaker is extremely inconspicuous. For the majority of people this is one of the most cosmetically acceptable hearing device types.
In the canal (ITC), mini canal (MIC) and completely in the canal aids (CIC):
ITC aids are smaller, filling only the bottom half of the external ear. You usually cannot see very much of this hearing aid when you are face to face with someone. MIC and CIC aids are often not visible unless you look directly into the wearer's ear.  These aids are intended for mild to -severe losses.
Invisible In canal hearing aids (IIC):
This type of hearing aid fitting is not visible when worn. This is because it fits deeper in the canal than other types, so that it is out of view even when looking directly in to the ear bowl (concha). A comfortable fit is achieved because the shell of the aid is custom-made to an individual ear canal after taking a mould of the patient’s ear.
"Open-fit" or "Over-the-Ear" OTE hearing aids are small behind-the-ear type devices. This type is characterized by a small plastic case behind the ear, and a very fine clear tube running into the ear canal. Inside the ear canal, a small soft silicone dome or a molded, highly vented acrylic tip holds the tube in place. This design is intended to reduce the occlusion effect.
Bone Anchored Hearing Aids (BAHA): The BAHA is an auditory prosthetic which can be surgically implanted. The BAHA uses the skull as a pathway for sound to travel to the inner ear. For people with conductive hearing loss, the BAHA bypasses the external auditory canal and middle ear, stimulating the functioning cochlea. For people with unilateral hearing loss, the BAHA uses the skull to conduct the sound from the deaf side to the side with the functioning cochlea. Individuals under the age of 5 typically wear the BAHA device on a headband. Over age 5, a titanium "post" can be surgically embedded into the skull with a small abutment exposed outside the skin. The BAHA sound processor sits on this abutment and transmits sound vibrations to the external abutment of the titanium implant. The implant vibrates the skull and inner ear, which stimulate the nerve fibers of the inner ear, allowing hearing.