Symptoms of Superior Canal Dehiscence Syndrome
The symptoms of superior canal dehiscence syndrome can, but don’t always, include:
- loss of hearing, or enhanced hearing of noises transmitted through bone
- the sense that the room is “jumping” at the sound of a loud noise
- vertigo, especially when straining or listening to loud noises
Symptoms of Meniere's Disease
The symptoms of Ménière’s disease include:
- fluctuating hearing loss
- loss of balance
- spontaneous periods of vertigo (an abnormal sensation of motion) that can last from two minutes to several hours
- tinnitus (ringing or other sounds in the ear)
- aural fullness (a feeling of pressure in the ear)
These symptoms can follow certain systemic infections such as mumps or measles, but in most cases the cause of Ménière’s disease remains a mystery.
Most patients have one affected ear, though for as many as 30% of patients both ears may become involved at some point during the course of the disease.
Getting the Correct Diagnosis
Diagnosis of Superior Canal Dehiscence
Superior canal dehiscence syndrome can be a tricky condition for physicians to diagnose. For one, it’s a congenital condition that’s not terribly common. Secondly, a tear in the bone can be difficult to interpret, even with the use of a CT scan. In fact, the chance of misdiagnosing superior canal dehiscence syndrome can be as high as 30 percent.
While it’s imperative that patients undergo a CT scan to determine the presence of a opening in the bone, the diagnosis of superior canal dehiscence syndrome is not based exclusively on these imaging studies. The characteristic eye movements evoked by sound and pressure stimuli as well as findings on tests such as vestibular evoked myogenic potentials are an important part of establishing the diagnosis.
Treatment for Superior Canal Dehiscence Syndrome
The treatment we’ve developed for superior canal dehiscence syndrome has relieved patients of the uncomfortable symptoms. The surgery involves plugging or resurfacing the hole in the superior canal using a patch of bone from the inside of the skull. The bone is attached using a special glue. We use image-guided surgery to help ensure that we find and repair the dehiscence.
Patients remain in the hospital three to five days after surgery. They may experience post-operative dizziness, which will slowly subside and may take two to three weeks to disappear completely. For a short time, they’ll watch out for signs of hearing loss. Steroids may help minimize post-operative inflammation. Additional physical therapy may help them overcome any remaining dizziness.
Treatment for Meniere's Syndrome
The treatment of Ménière’s disease focuses on managing the symptoms. The first step is to undertake a low-salt diet and begin a prescription of diuretics (medications that reduce fluid in the inner ear). Many patients begin to feel better with these measures. In extreme cases when the episodes of vertigo continue to be debilitating, surgery may be necessary. There are several procedures that reduce the pressure of excess fluid in the inner ear (such as endolymphatic sac decompression or shunting) or that sever the balance nerve to minimize the terrible sensations of vertigo (the procedure called vestibular neurectomy or vestibular nerve section).
An effective and minimally invasive treatment involves an injection of the antibiotic gentamicin directly into the middle ear. We have studied the treatment of Ménière’s disease and have determined that gentamicin can be given to patients with excellent results, curing the symptoms of vertigo without incurring hearing loss. This has shown to be an improvement over the standard treatment of which was shown to cause hearing loss in as much as ten percent of patients.
Electrical Stimulation to Restore Vestibular Function:
Cochlear implants, which can help restore hearing to profoundly deaf adults and children, are among the crowning achievements of synergistic research between neuroscientists and otolaryngologists. Unlike regular hearing aids (which simply amplify sound and thus rely on at least some normal ear function), cochlear implants directly stimulate the auditory nerve with electrical currents delivered by a set of electrodes slid into the cochlea.
In work recently begun in our laboratory, we are exploring the feasibility of using similar technology to restore balance and steady vision in patients severely affected by vestibular loss due to ototoxic drugs and other disorders. While a “vestibular prosthesis” is certainly a long way off, we are working to lay the scientific foundation upon which design of a clinically useful prosthesis can build.