Diabetes can cause many changes to the hearing mechanisms, including:
- Damage to the nerves and blood vessels of the inner ear cause the most common type of hearing loss, termed sensorineural hearing loss. Although this type of hearing loss cannot usually be cured, most cases can be treated with hearing aids. Info on assistive devices and hearing aids.
- People with diabetes often have less keratin, a protein that lines the ear canal which can cause hearing loss.
- One branch of the eighth cranial nerve, which carries sound signals from the cochlea to the brainstem, may experience deterioration of the sheath that protects its nerve fibers (demyelination).
- The tissue in the ear canal can also degenerate, affecting hearing.
- The cochlea can experience a thickening of its walls or the loss of hair cells.
- Chemical changes may affect the nerves’ ability to carry sound signals. The capillaries of the inner ear can also be thickened, affecting the ability of the ear to carry sound signals.
- Diabetics are also more prone to get external and middle ear infections. Repeated or chronic ear infections can also result in hearing loss.
As diabetes is commonly an autoimmune disorder, autoimmune inner ear disease may also contribute to hearing loss. Autoimmune inner ear disease is progressive hearing loss and/or dizziness caused by antibodies or immune cells which are attacking the inner ear. A reduction in hearing is accompanied by tinnitus (ringing, hissing, roaring) which occurs over a few months, and abnormal blood tests for antibodies.
Of course sometimes the problem is just an earwax build-up and the individual may simply have a doctor remove the wax.
Due to the abundance of evidence linking hearing loss to diabetes, diabetics should get their hearing tested regularly in addition to maintaining good glucose control.