Otosclerosis is a progressive middle ear disease which causes a conductive hearing loss. It usually begins in affected people between the ages of 10 and 30 and is twice as prevalent in women compared to men.
Over time the three small bones of the middle ear become fused together and then to the surrounding bone, adding both weight and stiffness. The three small bones are called ossicles and it is the ‘Ossicular chain’ which carries sound energy from the eardrum across to the inner ear. The ossicular chain terminates underneath the footplate of the stapes at the oval window, the opening to the Cochlear or inner ear.
The ear drum (tympanic membrane) is around 20 times bigger than the oval window. Along with the lever action of the ossicular chain this gives around a 28dB amplification of the sound entering the Cochlear. Where there is a large perforation in the ear drum or the ossicular chain has become fused this advantage can be lost, leading to what is known as a conductive hearing loss (because the sound is not being conducted efficiently across to the inner ear). In the case of Otosclerosis not only can the ossicular chain become rigid but further bone growth can add weight to the chain which can increase the hearing deficit even more.
As with other types of conductive hearing loss the inner ear is usually working well. This means that, rather like when you plug your ear with your finger, any internal sound is heard louder than normal. This means that the nature and types of tinnitus that present in Otosclerosis is often quite varied. The sensory deprivation caused by the conductive hearing loss can lead to a ‘raised central auditory gain’. This is where your brain is responding to the quiet by becoming more sensitive to all sounds, including normal nerve activity leading to common neuronal tinnitus that sounds like a constant tone or hiss. But you are also more susceptible to hearing what are known as somatosounds. These are normal noises made by the body such as blood pulsing, swallowing and chewing etc.
Although it is necessary to have any pulsatile tinnitus investigated by an ENT Consultant, it is recognised in all the literature around Otosclerosis that the first and most effective line of treatment is correcting the hearing loss.
Your ENT Consultant may discuss with you the possibility of surgery to correct the bone growth. While this can often be successful in improving the hearing and to a certain extent the tinnitus, they will usually wait until the condition is quite advanced as the surgery is not without a small degree of risk.
Well fitted hearing aids will need to take into account both the degree of inner ear loss and the conductive element of the hearing problem. They need to have ample power to follow any changes in your hearing and we would recommend they have access to high-quality streamed tinnitus therapy sounds. Although it can be tempting to opt for smaller custom devices we would recommend good quality ‘Receiver in the Ear’ hearing aids. These are capable of being adjusted a great deal more to keep up with any changes in your hearing over time. Why not book in to see one of our Tinnitus UK experts and start getting the help you need right away?