Lesser Known Disorders
Each issue of this series contains at least three lesser known disorders. Some of these disorders may contain subtypes which will also be presented. You will also notice that each disorder has a code. These codes represent the coding system for all disabilities and disorders listed in the Educator’s Diagnostic Manual(EDM) Wiley Publications.
Disorders in this issue:
HI 2.01- Cholesteatoma
Disability Category: Hearing Impairment
Definition
Cholesteatoma can be a congenital (present at birth) defect, but it more commonly occurs as a complication of chronic ear infection. Long-term inflammation and malfunction of the eustachian tube leads to chronic negative pressure in the middle ear (U.S. National Library of Medicine, 2004).
Explanation
According to the American Academy of Otolaryngology (2004), a cholesteatoma is a skin growth that occurs in an abnormal location, the middle ear behind the eardrum. It is usually due to repeated infection, which causes an ingrowth of the skin of the eardrum.
Cholesteatomas often take the form of a cyst or pouch that sheds layers of old skin that builds up inside the ear. Over time, the cholesteatoma can increase in size and destroy the surrounding delicate bones of the middle ear. Hearing loss, dizziness, and facial muscle paralysis are rare but can result from continuedcholesteatoma growth.
HI 2.01a-Acquired Cholesteatoma
A type of Cholesteatoma that occurs after birth
HI 2.01b-Congenital Cholesteatoma
A type of Cholesteatoma that is present from birth
HI 6.00 Syndromic Hearing Loss
Disability Category: Hearing Impairment
Definition
Syndromic hearing impairment is associated with malformations of the external ear or other organs or with medical problems involving other organ systems (Smith, Green & Van Camp, 2005).
Diagnostic Symptoms
The symptoms for Syndromic Hearing Loss will vary by disorder and as a result no general symptoms can be reported.
Further Key Points
Genetic causes of hearing loss can be “syndromic” or “nonsyndromic”. Syndromic means that a person has other related symptoms besides hearing loss. For example, some people with hearing loss are also blind. Usher’s Syndrome is one example. There are many different syndromes that have hearing loss as one of the symptoms. “Nonsyndromic” means that the person does not have any other symptoms related to the hearing loss. Whatever caused the hearing loss does not cause any other symptoms. The more common type of genetic hearing loss is “nonsyndromic” which includes 2/3 of all genetic hearing losses. A very common “nonsyndromic” hearing loss is caused by one gene known as Connexin 26 (abbreviated CX26). CX26 alone is the cause in about 1/3 of all children with a non-syndromic genetic hearing loss (National Center on Birth Defects and Developmental Disabilities, 2005).
Types of Syndromic Hearing Losses
HI 6.01-Aplasia
Definition
An aplasia is an abnormal development of either the bony or membranous portion of the inner ear (cochlea) (League for the Hard of Hearing, 2005; MedicineNet.com (2005).
Explanation
The disorders discussed in this section have a variety of symptoms. Therefore no generalized list of diagnostic symptoms can be made.
HI 6.01a-Michel aplasia
A type of Aplasia characterized by the complete absence of the inner ear and auditory nerve, resulting in total absence of hearing. It may appear in one ear (unilaterally) or both ears (bilaterally). Patients cannot be helped by either a hearing aid or a cochlear implant if the hearing nerve is absent. They may be assisted by a vibrotactile device (a device that augments remote voice communication with touch, by converting hand pressure into vibrational intensity between users in real-time).
HI 6.01b-Mondini aplasia
A type of Aplasia characterized by an abnormal development of the cochlea. The normal cochlea has two and one half turns. In Mondini Aplasia the turns may range from one to four. The most severe form results in a common cavity (no turns). It may occur unilaterally or bilaterally. Hearing loss can range from moderate to profound and is often progressive in cases where residual hearing is present. In less severe cases, hearing aids are beneficial. If the loss is too profound to be helped by hearing aids, cochlear implants are an option.
HI 6.01c-Scheibe aplasia
A type of Aplasia characterized by an abnormal formation of the cochlear membrane. The defect may be unilateral or bilateral. There may be residual low frequency hearing that is aidable. If not, a cochlear implant is an option.
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