Conductive Deafness

Conductive Deafness

Anatomy and Physiology of the Ear Click here

Conductive Hearing Loss: Conductive hearing loss occurs when sound waves are prevented from passing from the air to the fluid-filled inner ear. This may be caused by a variety of problems including buildup of earwax (cerumen), infection, fluid in the middle ear, a perforated eardrum, or fixation of the ossicles, as in otosclerosis . Other causes include scarring, narrowing of the ear canal, tumors in the middle ear etc. Once the cause is found and removed or treated, hearing usually is restored.

Deafness due to disease of the external ear, ear drum or mddle ear.

Causes


Causes for Conductive Deafness :

Audiogram and Impedance test results of a patient with Conductive Deafness

Evaluating Hearing Loss
Your Ear Nose Throat Surgeon will perform a number of examinations to determine the presence, extent, location, magnitude, and qualities of any hearing loss.

A physical exam, using an otoscope or ear microscope, will evaluate the ear canal and tympanic membrane. The nose, nasopharynx, and upper respiratory tract will also be examined as the ear and nose has close anatomical relationship and disease conditions in one often affects the other ( eg one becomes temporarily deaf during a “cold”.

 

Audiometry involves the presentation of pure tones each ear via headphones or through a bone conductor transducer. A range of frequencies is used, and the patient’s pattern of response is analyzed.

 

Acoustic Reflex testing measures the contraction of a tiny ear muscle that responds to sounds at different volumes. The loudness at which the reflex occurs, or the absence of the acoustic reflex, provides important information.

 

Tympanometry measures the impedance of the middle ear to sound. It uses an airtight seal and a microphone to deliver sound into the ear canal. The amount of sound that is absorbed or reflected from the middle ear is measured at the microphone at normal, positive, and negative air pressures. Tympanometry is useful in identifying middle-ear effusions in children. It is often used as a confirmatory test when microscopic examination is inconclusive.

 

Other tests: patients with conductive hearing losses may require computed tomography (CT) scans of the temporal bones. Those with unilateral or asymmetric sensorineural hearing loss should have magnetic resonance imaging (MRI) of the head. Many specialized centres do Electro-Nystagmography (ENG) for assessment of vertigo

 

Treatment of  Conductive deafness

Treatment of  Conductive deafness depends on the cause and can be medical,surgical or by hearing aid.

Medical treatment of Conductive deafness:

Surgical treatment of Conductive deafness:

Myringotomy – Incision and Drainage of fluid from middle ear

Myringotomy and insertion of ventilation tube (grommet) for drainage

Myringotomy and insertion of ventilation tube (grommet) with Adenoidectomy.

Myringoplasty – Fashioning a new ear drum

Tympanoplasty – Removal of ear middle ear disease and fashioning a new ear drum

TympanoMastoidectomy – Removal of disease in middle ear and mastoid bone (usually cholesteatoma) with reconstruction of the ossicular chain.

Stapedectomy and Stapedotomy for Otosclerosis.

 

Hearing aids: In selected cases of Conductive deafness not remediable by surgical means.

While a hearing aid is an effective help – it is not a cure for hearing impairment.

Hearing aids can not restore our original hearing ability, but they can help us to make the very most of the hearing ability we have left. Today’s hearing aids are intricate technical instruments, which are individually adjusted to the user’s own specific hearing loss. Even so, it takes time to become used to all the new, amplified sounds ­especially if we have lived with a hearing loss for some time and have forgotten how noisy buses and cars sound.

Most individuals with hearing loss can bene­fit from amplification. The goal of amplification is to make speech audible. The most common types of hearing aids range in size from fitting behind the ear (BTE), in the ear (ITE), and in the canal (ITC) to completely in the canal (CIC), the small­est. The style of hearing aid can be limited by the degree of loss. For example, an individual with severe to profound hearing loss will require a BTE. A lesser hearing loss should benefit from the smaller styles such as ITE or CIC.

Audiogram and Impedance testing determines the levels of hearing for hearing aid can be selected.

The most common types of hearing aids range in size from fitting behind the ear (BTE), in the ear (ITE), in the canal (ITC) and completely in the canal (CIC), the small­est. The style of hearing aid is limited by the degree of loss. For e.g., an individual with severe to profound hearing loss will require a BTE. A lesser hearing loss should benefit from the smaller styles such as ITE or CIC and IIC.