Article - Hearing Impairment and EDS

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From the UK website:

HEARING IMPAIRMENT AND EHLERS-DANLOS SYNDROME

By

Mr M. Hawthorne FRCS Consultant ENT Surgeon

Introduction

It is extremely rare for a diagnosis of Ehlers-Danlos Syndrome to be made

with hearing impairment as the sole abnormality. Most ENT surgeons will

usually be told by the patient that they have Ehlers-Danlos Syndrome, but

few are aware of the effects of this condition on the middle ear.

The conducting mechanism of the middle ear is the primary site of

abnormality in patients with Ehlers-Danlos Syndrome. As most people are

aware sound hits the tympanic membrane and is conducted across the

air-filled middle ear to the inner ear by three tiny bones known as the

malleus, incus and stapes (hammer, anvil and stirrup bones). Hypermobility

of the joints between these bones means that sound is not conducted

effectively across the middle ear cleft. In addition to that the ligaments

which are attached to these bones may also be affected by the condition

causing an overall laxity of the conducting mechanism. This will present as

hearing impairment of gradual onset.

Presentation

Significant hearing impairment due to Ehlers-Danlos Syndrome is rare. In my

experience patients usually become aware of a hearing impairment in middle

life. Paradoxically, some patients are aware that they hear better in places

of background noise. This is because people tend to raise their voices in

areas of background noise such as among a group of friends on a Saturday

evening in a public house.

The eardrum will appear normal on inspection and tests will reveal that the

inner ear is functioning normally but that there is a conductive hearing

loss due to loss of energy across the inner ear conducting mechanism.

Important Differential Diagnosis

There is a much more common inherited disorder of hearing known as

Otosclerosis which can be easily confused with the type of hearing

impairment seen in Ehlers-Danlos Syndrome. It is vitally important for the

ear surgeon to be able to differentiate between the two. Like Ehlers-Danlos

Syndrome, Otosclerosis also runs in families, the eardrums are normal, and

there is a hearing loss due to an abnormality of sound conduction across the

middle ear.

Otosclerosis may be effectively treated by an operation known as

stapedectomy. However, an attempt to undertake a stapedectomy on a patient

suffering from Ehlers-Danlos Syndrome could easily end in disaster with a

total loss of hearing and a severe disruption of balance.

In Otosclerosis the joint between the stapes bone and the inner ear is stiff

whereas in Ehlers-Danlos Syndrome the joint is likely to be hypermobile.

Surgical interference with the stapes in circumstances with a hypermobile

stapes / inner ear joint could lead to dislocation of this joint with

disastrous results.

Treatment

The safe and effective way of treating the mild to moderate hearing

impairment which occurs in Ehlers-Danlos Syndrome is with a hearing aid. If

necessary additional aids can be provided for the home such as a door bell

which causes the kitchen or sitting room lights to flash, a television aid,

a vibrating alarm clock.

Hearing aids are available for free from National Health Service Departments

of Audiology. The provision of environmental aids for the home varies from

social services area to social services area but information can usually be

obtained from the Department of Audiology at the nearest hospital to where

the patient lives or from the Department of Social Services.