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CNCS - Cochleovestibular Nerve Compression Syndrome

WHAT IS COCHLEOVESTIBULAR NERVE COMPRESSION SYNDROME?

Cochleovestibular Nerve Compression Syndrome (CNCS) is the term used to describe a group of audiovestibular (hearing and balance) symptoms thought to be caused by a blood vessel or benign (non-cancerous) tumor compressing the cochleovestibular nerve at the seventh and eighth cranial nerve complex.

WHAT ARE THE SYMPTOMS OF COCHLEOVESTIBULAR NERVE COMPRESSION SYNDROME?

The symptoms of CNCS can include a variety of vestibular and auditory symptoms including persistent vertigo, continual balance problems and “quick spins” that result as a symptom of acquired motion intolerance. Frequently, individuals with CNCS additionally have hearing loss and/or ringing in the ear know as tinnitus.

HOW IS COCHLEOVESTIBULAR NERVE COMPRESSION DIAGNOSED?

Initial treatment for CNCS begins with a series of tests in order to exclude other conditions with overlapping symptoms such as Meniere’s disease, migraine, labyrinthitis, acoustic neuroma, and fistula. These can include:

  • Auditory Brainstem Response Testing (ABR);
  • Head imaging including Magnetic Resonance Imaging (MRI) or CT Scan;
  • Balance testing, including electronystagmography (ENG) or Computerized Dynamic Posturography (CDP);
  • Audiometry (hearing testing);
  • Neurological consultation;
  • Blood work

WHAT IS THE TREATMENT FOR COCHLEOVESTIBULAR NERVE COMPRESSION?

After a comprehensive medical examination has been completed by an otolaryngologist and an audiologist, medications can be prescribed as initial treatment to attempt to abate the severe motion intolerance that results from CNCS. If medical treatment does not satisfactorily reduce the symptoms, surgical intervention with a procedure called Microvascular Decompression (MVD) can be performed.

Surgery includes lifting the structure causing the compression (usually a blood vessel) off the affected nerve. In most cases a barrier is placed between the two structures (such as Teflon felt) in order to prevent further compression in the future.

The most common side-effect from MVD surgery is the potential for an acquired hearing loss or diminished hearing resulting from performing surgery in the region of the seventh and eighth cranial nerves. The eighth cranial nerve (VIIIth) or auditory nerve is linked to hearing and balance. Sometimes as a result of relieving pressure from the nerve, weakness along one side of the face can appear where it did not exist before, a condition similar to Bell’s Palsy. In severe cases, eye complications can occur because of the loss of the blink reflex. If the face becomes completely paralyzed, a nerve can be grafted in the place of the facial nerve which should restore some facial sensation and movement within a year of surgery, however, this function will never return to normal levels.

CONCLUSION:

If you have experienced any change in hearing or experience dizziness, you should consult an Otologist for a comprehensive medical examination. Otologists are otolaryngologists (ENTs) who have undergone two additional years of training and specialize in issues related to hearing and balance only. With appropriate medical treatment and therapy, individuals with cochleovestibular nerve compression syndrome can make a partial or even full recovery.

References

  • Schwaber, M. K. and J. W. Hall (1992). "Cochleovestibular nerve compression syndrome. I. Clinical features and audiovestibular findings." Laryngoscope 102(9): 1020-9.
  • Schwaber, M. K. and W. O. Whetsell (1992). "Cochleovestibular nerve compression syndrome. II. Vestibular nerve histopathology and theory of pathophysiology." Laryngoscope 102(9): 1030-6.

 

 

 

 

 


 
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