Thursday, October 25, 2012

Hearing Loss (Part Two)


 


Hearing loss treatment

The treatments vary depending on the type, site/s and severity of hearing loss. This is best assessed and diagnosed by an Ear, Nose & Throat Specialist.

The appropriate treatment may be conservative observation, hearing aiding and /or ear surgery. For children with persisting “glue ear” especially when in both ears with notable signs of language and /or attention problems, a ventilation tube (grommet) can be placed into the eardrum by surgery. For patients with a perforated eardrum, this can be repaired by surgery.

For patients with bilateral complete deafness, a cochlear implant sound processor should be considered. This re-stimulates the deaf ear using an electrode array and some very clever speech software processing. The new sound that is heard will indeed be different. Speech and hearing rehabilitation exercises to re-learn these sounds would be required. Children do better than adults with these cochlear implants. Studies have shown that a child’s brain has a higher neuro-plasticity than an adult, and therefore a greater capacity to adapt to new sounds and learning development.

 

Hearing aids

Hearing aids are often the first consideration for patients with hearing disabilities. These aids can be similarly considered like glasses for visual problems. They do not require surgery and the advanced technology is relatively inexpensive. Patients can used them when they want and remove them as necessary.

There are many different types of hearing aids available. They vary in size, quality, performance and therefore, price. Hearing aids should always be tailored to the different needs and hearing disability of the user. Hearing aids are however, not without their own problems. Patients may well find them uncomfortable or conspicuous to wear. This perhaps more so if the benefit offered is insufficient to meet the patients’ expectation and needs.

Conventional hearing aids require a sound leak proof occlusion of the ear canal by the ear mold in order to work well. Patients may find the fitting ear mold a little uncomfortable to use. Also, slight movement could alter its position easily and this can create feedback whistling sound, when the amplified sound leaks out of the ear canal, and re-enters the microphone of the same hearing device. This is similar to the whining feedback during karaoke sessions when the sound is picked up by the same microphone in a reverberating circuit.

When properly prescribed and fitted, conventional hearing aids are a good option to rehabilitate most hearing problems.

 

Baha (Bone Anchored Hearing Aid)

The baha, as its abbreviation suggests, works by direct bone conduction of sound to the cochlea via a sound processor and titanium implant on the skull. As the sound conduction is entirely via bone conduction to the cochlea, the external pinna, external ear canal and middle ear bones are not required. In fact they are completely bypassed. Hence the baha is suitable for those without an outer ear and occluded ear canal (microtia and congenital aural atresia) and those with poor middle ear conduction problems (mastoidectomy, loss of ossicles, otosclerosis).

The baha is especially ideal for patients with one-sided complete hearing loss, aka single-sided deafness (SSD). These SSD patients experience a poor perception of sound on one side especially on the phone, during meetings and dinners, and in noisy environments. The baha “captures” sound from the deaf side, and transmits it to the only working ear on the opposite side through bone conduction through the skull. The patient is then able to appreciate sounds and conversation on the deaf side, and finds themselves once again, enjoying their sound rich social environment.

One of the greatest advantage of the baha is that it is the only implantable hearing processor that allows people “to try before they buy”. By using a soft band applicator as a connection to the skull, the baha can be tried without surgery required. If the user likes the baha, they can choose to continue using the softband approach, or undertake a more securely applied baha via a surgical titanium implant to the skull, just behind the ear. Certainly, for the surgical installed baha, as there will be no intervening soft tissue unlike the softband trial, the sound heard will be clearer after the BAHA is implanted.

The surgery is a single-stage surgery, done with a minimal invasive implantation, maximizing the preservations of tissues. It takes around 15 minutes to complete the whole procedure and can be done within a clinical setting.

 

Summary

Hearing loss should be identified early especially with children for their speech and language development. Timely treatment by medication, surgery or hearing aiding can then be advocated.

Hearing aids and sound processors like the baha and cochlea implant, allow sounds to be heard. The sound may not be as rich as the normal ear, but the improvement beyond the hearing disability improves our patients’ social and professional interaction and enjoyment significantly.

 
 
Reference information: entific.com.hk

The information aims to provide educational purpose only. Anyone reading it should consult ENT Specialists before considering treatment and should not rely on the information above.