Issue # 46

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.

HI 7.00- Vestibular Schwannoma (Acoustic Neuroma)

Disability Category:  Hearing Impairment

Definition

Vestibular schwannoma (also known as acoustic neuroma, acoustic neurinoma, or acoustic neurilemoma)   is a benign, usually slow-growing tumor that develops from the balance and hearing nerves supplying the     inner ear. The tumor comes from an overproduction of Schwann cells—the cells that normally wrap around nerve fibers like onion skin to help support and insulate nerves. As the vestibular schwannoma     grows, it presses against the hearing and balance nerves, usually causing unilateral (one-sided) or              asymmetric hearing loss, tinnitus (ringing in the ear), and dizziness/loss of balance (National Institute on    Deafness and Other Communication Disorders, 2005a).

 

Diagnostic Symptoms

Diagnostic symptoms of Vestibular Schwannoma include (Mayo Clinic, 2004):

  • Hearing loss in one ear
  • Ringing (tinnitus) in the affected ear
  • Dizziness
  • Loss of balance

 

Further Key Points

Scientists are working to better understand how the gene works so they can begin to develop gene therapy                to control the overproduction of Schwann cells in individuals with vestibular schwannoma. Also, learning    more about the way genes help control Schwann cell growth may help prevent other brain tumors.

    To top


    HI 7.01 Bilateral Vestibular Schwannomas

    Disability Category: Hearing Impairment

    Definition

    A type of Vestibular Schwannomas that affects both hearing nerves and are usually associated with a genetic disorder called neurofibromatosis type 2 (NF 2). Half of affected individuals have inherited the disorder from an affected parent and half seem to have a mutation for the first time in their family       (National Institute and Other Communication Disorders, 2004).

     

    Explanation

    Each child of an affected parent has a 50 percent chance of inheriting the disorder. Unlike those with a   unilateral vestibular schwannoma, individuals with NF2 usually develop symptoms in their teens or early  adulthood. In addition, patients with NF2 usually develop multiple brain and spinal cord related tumors.They also can develop tumors of the nerves important for swallowing, speech, eye and facial movement, and facial sensation (National Institute and Other Communication Disorders, 2004).

      To top


      OI 3.04 Hydrocephalus ex-vacuo

      Disability Category: Orthopedic Impairment

       

      Definition

      Hydrocephalus ex-vacuo occurs when there is damage to the brain due to the effects of stroke or traumatic Institute for Neurological Disorders and Stroke, 2005c).

      Explanation

      What is termed “hydrocephalus ex-vacuo” occurs when there is damage to the brain caused by stroke or injury, and there may be an actual shrinkage of brain substance. “Hydrocephalus ex-vacuo” is essentially only hydrocephalus by default; the CSF pressure itself is normal (Medicine.net, 2004)

        To top


        OI 3.05 Non-communicating hydrocephalus

        Disability Category: Orthopedic Impairment

        Definition

        Non-communicating hydrocephalus—also called “obstructive” hydrocephalus—occurs when the flow of CSF is blocked along one or more of the narrow pathways connecting the ventricles (National Institute for Neurological Disorders and Stroke, 2005c).

         

        Explanation

        In most cases it refers to a blockage between the third and fourth ventricles at the level of the Aqueduct of Sylvius, so called aqueductal obstruction. This can be due to scarring of this passage (aqueductal stenosis), or a tumor (in most cases a tectal glioma). When the obstruction is due to a tectal glioma it is important to realize that the tumor has only a 10% chance for growth and the only treatment required is for the hydrocephalus. Additional treatments for the tumor are only delivered if growth is documented(Hyman-Newman Institute for Neurology and Neurosurgery, 2005).

          To top

          Download this Issue

          To Download a PDF file version of this Issue of the NASET’sLesser Known Disorders in Special Education Series CLICK HERE

          To top

           


          Use the “Recommend” and “Tweet” button below to let your friends on Facebook and Twitter know about this article.

          Become a Member Today

          Join thousands of special education professionals and gain access to resources, professional development, and a supportive community dedicated to excellence in special education.

          Become a Member Today
          Chat with NASET