Although hearing loss or deafness is not a common symptom of multiple sclerosis, people can experience problems with hearing, such as tinnitus (ringing in the ears) or sudden hearing loss. Other hearing problems that can occur include the difficulty in understanding speech against a noisy background or being more sensitive to noise (hyperacusis).
MS-related hearing loss can happen suddenly or over the course of a couple of days. Hearing loss is defined as a loss of at least 30 decibels - this is about half as loud as a normal conversation. Hearing loss usually occurs in one ear only but occasionally both ears are affected.
Hearing problems caused by MS are thought to be due to damage to the brainstem - the part of the brain that is also involved in vision and balance. Problems are often associated with other brainstem symptoms such as tinnitus and vertigo.
Sudden hearing problems can show that you are having a relapse. Treatment with steroids may speed up recovery of hearing. Hearing problems may also be linked to sensitivity to heat. If this is the case, your hearing may get worse when your body temperature rises and then return to normal when you cool down.
In one study of 253 people with multiple sclerosis, only 11 people (4.5%) were found to have experienced sudden hearing loss over five years. For seven of these people, it was the symptom that led to their MS diagnosis - suggesting that this symptom tends to occur early in the disease.
Because it is an unusual MS symptom, it is important that other causes of hearing problems are ruled out. These can include excessive ear wax, medications that can affect your ears, or other illnesses. Hearing loss can also be caused if you are exposed to loud noise or by injury. You may be referred to an ear, nose and throat specialist or an otolaryngologist for an assessment.
