What is Superior Semicircular Canal Dehiscence?

Jul 28

Superior Semicircular Canal Dehiscence (SSCD) is a condition where one of the receptors in your inner ear develops a perforation. The inner ear contains receptors called semicircular canals, which are fluid-filled membranous tubes encased in bone. The bone surrounding the superior canal can wear away and become very thin, or develop a small hole called a dehiscence. This creates a communication between the normally closed off auditory system to the vestibular system. This pressure that moves through the vestibular system creates many of the symptoms you may be feeling such as vertigo, or the sense of motion, and exaggerated forms of hearing.

How Common is Superior Semicircular Canal Dehiscence?

The average age of onset appears to be in the mid 40s. Roughly 1-2% of the population has an abnormally thin bone covering the superior canal. The connection between thin bone and symptoms is murky, as some people with thin or dehiscent bone on CT scans will have no symptoms. Others will have an intact bone and present with all the symptoms of frank SSCD.

The increasing prevalence of SSCD in old age suggests it to be more commonly an acquired condition rather than a congenital one (2).

What are the Symptoms of Superior Semicircular Canal Dehiscence?

The main symptom experienced with SSCD is vertigo. This usually happens after experiencing a loud sound (Tullio Phenomenon) or when external pressure is applied to the affected ear (Hennebert Sign) (3). Oscillopsia, the appearance of movement of stationary objects, is also quite common. Other symptoms can include a "whooshing" sound in the ear known as pulsatile tinnitus or ringing in the ears that have no distinct pattern. A symptom known as autophony can also be present, in which you may hear your voice as extremely loud or distorted. Many sounds will typically be exaggerated with SSCD, such that chewing may be uncomfortably loud. Many people describe being able to hear their own eyes move or chewing. This can be very intrusive, disturbing, anxiety provoking, and crazy-making (14).

How Does the Vestibular System Work?

Our inner ear contains a series of membranous canals encased in bone known as the vestibular labyrinth. The semicircular canals are fluid-filled tubes that contain specialized hair cells. When the head moves, the inertia of the fluid makes it take a moment for the fluid to start to move. This bends the hair cells, which activates the vestibular nerve, and impulses are conducted into the brainstem, cerebellum and brain. These inputs allow the brain to perceive where the head is in relation to the body and gravity, as well as what direction the head is moving.

There are three canals on each side, superior, lateral, and posterior. These systems are pressure sensitive, and need bony support to function properly.

The bone that encases the top portion of the superior canal is naturally very thin. This makes it vulnerable to trauma and bone erosion. When functioning properly, this system is closed off to vibrations from external sound. The fluid within these vestibular canals only moves when our head moves and remains still when we’re not moving. This change from head still to head motion is how our brain perceives angular or linear direction.

When SSCD occurs, the fluid within the canals can be influenced by pressure changes with the cochlea or hearing portion of the inner ear. The pressure comes in from the middle ear and some of that force is transferred into the labyrinthine or canal system. This pressure moves the fluid which stimulates the canals and tells the brain that the head is moving. This perceived motion or stimulation is what causes the symptoms of vertigo and dizziness most often associated with this condition (15).

What Causes Superior Semicircular Canal Dehiscence?

There are a number of accepted causes of SSCD at present. SSCD may be a genetic variant, with symptoms initially presenting in early adulthood. Genetic SSCD can manifest with bilateral symptoms in one third of all cases (4).

SSCD may also be an acquired condition from repeated low-intensity cranial trauma. One form of this can be erosion from perilymphatic fluid, cerebrospinal fluid, or even blood flowing normally around this area (1).

Head injuries and skull base trauma in motor vehicle accidents is a common cause of SSCD. Injuries to the skull received during combat sports have also been associated with SSCD (3).

How is Superior Semicircular Canal Dehiscence Usually Treated?

If the symptoms of SSCD are not severe or disabling, conservative treatment is often the best option. This may include low salt diets or vestibular therapies. In some cases, the symptoms can be severe enough to warrant surgery. Surgical options are generally safe and effective (5), and we have seen patients report waking up after surgery finally feeling like they have stopped moving. That said, no surgical procedure can even be 100% effective, and the rate of success varies with different procedures and providers. It is not uncommon for patients to have their symptoms resolve with surgery, only to recur at a later date, or for symptoms to incompletely resolve (1).

How is the NeuroRescue Program Different?

While SSCD is a relatively rare condition, we treat SSCD patients on a regular basis. When symptoms are severe, our treatment is focused on helping manage symptoms until a surgical correction can take place. Once you have recovered from surgery, we can shift our focus towards helping reintegrate your inner ear signals with your visual and proprioceptive systems. When symptoms are less severe or surgery is not indicated, we focus on visual-vestibular-proprioceptive integration therapy, to help you regain your balance and stability, and to reduce your oscillopsia.

The unfortunate reality of living with SSCD is that over time the brain begins to adapt to the inappropriate signals from the inner ear as being the new normal. Superior semicircular canal dehiscence can be a hard condition to diagnose. It can take years of struggling with vertigo and nausea and seeing countless providers before an appropriate diagnosis is finally made. By that time the brain will have learned to partially compensate for the impaired vestibular reflexes. The brain and cerebellum have a wonderful capacity to adapt to changes in receptor inputs, but once the SSCD is surgically repaired, the brain’s adaptive compensation may create as many problems as it originally solved. While people often describe marked improvement in their symptoms following SSCD surgery, in almost all cases there are residual sensations of dizziness, nausea, balance difficulty, and cognitive challenges that need to be addressed. These persistent symptoms often do not respond well to traditional visual and vestibular therapy. These are exactly the symptoms the NeuroRescue program can effectively address.

The therapies in your NeuroRescue Program will be determined by the specifics of your condition and your diagnostic testing results. Your treatment may involve various types of dietary therapies to stabilize vestibular receptor function (6), or specific exercises to retrain the integration of your eyes and inner ear during head movement (7). It may involve specific forms of eye exercises to enhance your stability (8), or transcutaneous electrical stimulation to stimulate your vestibular system (9). It may involve specific types of visual stimulation exercises (10), or visual stimulation coupled with specific head movements (11). It may involve the use of transcranial magnetic stimulation to decrease your dizziness (12), or even the use of exercises performed in a virtual reality environment (13). All of our therapies are tailored to the specific realities of your case as determined by your unique diagnostic findings. No two NeuroRescue Programs are alike.

How Does the NeuroRescue Program Work?

We design your unique NeuroRescue Program to be among the most comprehensive diagnostic and therapeutic protocols available today. We create individual NeuroRescue Programs based on a comprehensive analysis of every relevant neurological system and pathway, using gold-standard, cutting edge neurodiagnostic technologies and examination procedures and state-of-the-art therapies.

We begin with your Discovery Day, wherein we perform a comprehensive history of not only your condition, but your life on a timeline. This allows us to dive deeply into your case and see all of the factors that led to where you are now. It helps us uncover hidden problems and associated conditions that may be making it difficult for you to move your recovery forward.

Our examination allows us to identify the areas and pathways of your brain that are involved in your unique SSCD presentation. We begin by precisely quantifying the function of your visual, vestibular, and proprioceptive systems through computerized analysis of your eye movements, your inner ear reflexes, and your balance in a host of different sensory conditions.

We employ technologies including Videooculography and Saccadometry to measure several classes of eye movements. We use Video Head Impulse Testing to measure the function of your inner ear, and Computerized Dynamic Posturography to assess your balance in different sensory conditions.

We use NeuroSensoryMotor Integration testing to evaluate hand-eye coordination and cognition, and Virtualis testing to assess dynamic eye tracking and perception of vertical in a virtual reality environment.

We combine all of this with a comprehensive physical and neurological examination of your sensory, motor, autonomic, and cognitive systems. We review any relevant laboratory testing, radiological imaging, and prior neurodiagnostic testing, and integrate that information with our findings.

We use this information to identify which parts of your nervous system are working properly, which systems are struggling, and the precise point at which your systems fatigue.

We can then design a NeuroRescue Program that is unique and specific to your brain, and yours alone. Your NeuroRescue Program works to rejuvenate and reintegrate the damaged neurons and pathways in your central and peripheral nervous systems. It works to improve energy, endurance, and functional capacity within your involved fragile systems.

We use our technologies and procedures to not only see what we need to address, but also when it is time to stop and let you rest. We address your impaired neurological function from multiple angles of therapy, and provide metabolic support to improve neurological recovery.

While we cannot bring back neurons that have been lost, your NeuroRescue Program allows us to take the pathways that remain and maximize their efficiency and endurance. And by focusing on the integration of systems, we can do more than just get pathways working better, we can get them working together again. This gives us our best opportunity to return you to living a healthy, vibrant, and fulfilling life.

Your Next Best Step:

To see if the NeuroRescue Program is right for you, contact one of our patient care coordinators to schedule your Discovery Day.

And remember, it’s never too late to start getting better.