Understanding Bone Conduction Hearing Loss and Management.

 The term Bone Conduction Hearing is being widely used now, whenever we hear this, we understand it by the name the transmission of sound through bones.

Let's try to understand the term from a wider perspective on how it works, causes, how it affects the life of individuals, and the solution to it. In the first blog we will be covering an overview of it, but later will go into extensive details.

Ear as organ if the hearing is divided into three regions:

a) Outer Ear (works as a collector of sound)

b) Middle Ear (works as a transmitter of sound)

c) Inner Ear (works as a sensor to sounds, changes the sound from acoustic to electric)

Normally the sound is collected by Pinna which through the internal auditory canal before transmitting the sound to the eardrum the collective effect of the head, pinna, and the ear canal is that the sounds are amplified by 10 to 15dB in 2000 to 4000Hz region. As the sensitivity to the sound is highest in this frequency region.

The eardrum works as a wall between the outer ear and the middle ear and separates the two. The eardrum vibrates in response to the sound waves transmitted through the ear canal, creating vibrations in the eardrum. 

These vibrations then transmitted through a chain of bones i.e. Malleus, Incus, and Stapes. Stapes is even known to the smallest bone in the human body. The transmission enhances the acoustic transfer in the ear, we can understand it by one fact that if the transmission of sound is not done through the bones it can give a hearing loss up to 30decibels(dB).

The In and Out pushing of the bone chain create pressure changes in inner ear fluids, which stimulates the inner ear structures i.e. hair cells, they convert the acoustic signals to neural impulses. These neural impulses are further transmitted through the Auditory nerve to the brain, which further processes it and makes us hear the sounds.

In all this, there is one more very important organ that is part of the middle ear is the Eustachian tube, which is connected to the middle ear through nasal air passages. Eustachian tube operates like a valve helping in equalizing the pressure on either side of the eardrum. The easiest and common way is to understand it is when we are flying in airplanes we feel the eardrum getting pulled which gets better with swallowing, as with swallowing we maintain the air pressure inside and outside of the eardrum.

Without a normal Eustachian tube function there is a reduction in efficiency of the middle ear, resulting in reduced acoustic energy transfer to the inner ear.

Causes:

There are various causes due to which one can have a loss of transmission of sound in the outer and middle ear which is called Conductive Hearing loss.

Possible causes:

* Aural Atresia

* Microtia

* Acute or Serous Otitis Media

* Chronic Suppurative Otitis Media

* Otitis Externa

* Otosclerosis

* Cholesteatoma

* Other Ossicular diseases

* Traumatic Injury to Middle Ear

* Perforated Eardrum

* Eustachian Tube Dysfunction

* Barotrauma

Conductive hearing loss makes all sounds seem faint or muffled. The hearing loss is usually worse at lower frequencies. 

Symptoms:

* Muffled Hearing

* Sudden or steady loss of hearing

* Fullness or stuffy sensation in the ear

* Dizziness

* Draining of the ear

* Pain or tenderness in the ear

Management:

If you are experiencing hearing loss, you should first visit an ENT or otolaryngologist, who can make a specific diagnosis for you. It will involve a hearing test (audiogram) by an audiologist to determine the severity and type of hearing loss.

Based on the result the treatment option might include: 

* Medical Treatment

* Surgery to address the cause

* Evaluation and fitting with Bone Conduction Hearing Devices

Bone Conduction Hearing Devices there are several wearing options one can opt form: 

               Spectacle Devices

               Soft Band 

                Head Band