What is the Vestibulo-Ocular Reflex and How is it Tested?

Ways Professionals Test Patients for Vestibular Dysfunction

Have you ever thought about how it's possible to see clearly even though our heads are moving? Most people think that the ears are just for hearing, but actually, there are nerve pathways between our inner ears and our eye muscles which drive our eye movements to keep things stable-looking when the head moves. This is called your Vestibulo-ocular Reflex (VOR). At anything other than very slow speeds, we need our inner ears to give the brain accurate information about head motion so that the brain can, almost instantaneously, tell the eye muscles what to do to keep images looking clear.  If this information is not correct, things will appear blurry or jumpy when moving – there is a term for this: oscillopsia.

Try it!  Look at a small number or letter at arm’s length in front of you and turn your head slightly back and forth quickly.  If your inner ears are working properly, your eyes are being told to move the opposite way of your head movement, at the same speed as the head movement, so that your target still looks clear for you.  A normal vestibulo-ocular reflex stabilizes your eyes no matter what movements your head is making.

How Vestibular Rehabilitation Professionals Evaluate the Vestibulo-ocular Reflex

There are ways that vestibular rehabilitation professionals can evaluate this reflex in patients.  One is called the Head Thrust or Head Impulse Test.  This is where we have you look at a distinct target (often just the tip of the tester’s nose) while the tester gives your head a very small but rapid and unpredictable movement.   We look for how well you keep your eyes on the target, and if there is an error in a particular direction of movement, it suggests a problem with the reflex, and helps us figure out what part of the inner ear isn’t doing its job.   Testing can also be done by testing what is called Dynamic Visual Acuity (DVA).  This is where your ability to read a particular eye chart while the head is not moving, is compared to your ability when the head is being turned back and forth at at least 1 Hz (one back and forth per second).  Depending upon how much your ability to read the chart worsens when moving, this can also indicate problems with the vestibulo-ocular reflex (VOR).  There are also computerized versions of this type of testing for greater precision.

Testing the VOR is only one of many things we evaluate in those with dizziness and balance disorders, but it is a key part of the testing.  This is because it can give us an idea whether or not your ears are sending your brain accurate information about your head movements, and if not, how this is affecting your ability to see while you are moving – which is pretty important!

Feel free to contact us – we are here to help you!

How Can the Inner Ear Make Me Unsteady?

Helping You Understand the Inner Ear

The ear is for hearing isn't it? I've been told that it is involved in balance and that ear problems can make you unsteady. How does that work?

Inertia, Gravity and Otoconia - Detecting Our Head Movements and Positions

In addition to the hearing organ, the inner ear contains the vestibular apparatus, which detects all head movements and positions.  This apparatus includes organs that contain calcium carbonate crystals (otoconia, or “ear rocks”) in gel.  Sensory hairs poke into the gel, so when the weight of the crystals shifts the gel due to linear acceleration, deceleration or tilt, the hairs get deflected.  These hairs are attached to nerve endings, so when they get moved, a signal is relayed to the brain telling us about what sort of motion is taking place and what orientation the head is at with respect to gravity.  The brain then uses this information to orient our eye position so that we can see clearly, and to tell our bodies what adjustments to make in order to keep our balance.

So if you are stopping or starting at a light, beginning to going up or down in an elevator, rocking on a boat, or just tilting your head and body a little, you can thank this part of the inner ear for helping you understand what is happening.   If these organs are not working properly in one or both ears, then you won’t be getting accurate information about your head position or certain head movements, in which case it’s pretty easy to see how this could make a person feel unsteady!  If your inner ear(s) aren’t telling you accurately where upright is, and if this information isn’t matching what your eyes see or your body feels, then you will likely feel off-balance.   (The inner ear also contains organs that don’t rely on gravity but instead detect angular head movements.  Problems here can create dizziness and vertigo, and this area will be explained next time.)

Fortunately, well-trained vestibular rehabilitation therapists can help people compensate for inner ear problems and improve their balance and orientation.  If you or anyone you know is experiencing dizziness or imbalance, feel free to contact us – we are here to help you!  

You can also find out more information about the inner ear balance system at the Vestibular Disorders Association .

How We Help BPPV in Older Adults

BPPV a Common Cause of Dizziness in Seniors

BPPV happens when loose crystals (otoconia) fall out into one of the canals

One of the most common causes of dizziness in seniors is Benign Paroxysmal Positional Vertigo, or BPPV.  This happens when calcium carbonate crystals (otoconia), that we all have in one part of the inner ear, become displaced into one or more of the inner ear’s semicircular canals. When otoconia move into one of the inner ear’s semicircular canals where they aren’t supposed to be, that canal sends different information to the brain about certain head movement than the other ear.  Both ears should be saying the same thing about what our head movements are, and they should be agreeing with what our eyes are seeing and our joints are feeling.  When there is a mismatch in these systems, it makes us feel dizzy.  BPPV is the most common cause of vertigo, which is an illusion of the room spinning or moving.

What Happens in the Inner Ear When the Room Starts Spinning?

Taking apart what's really happening to a BPPV patients as they experience vertigo can help patients to feel less frightened by it. The start of the problem often happens at night when a person is laying down.  Loose crystals can fall out into one of the canals, and when the person gets up in the morning these crystals are trapped out in the canal.  From that point forward any time the person moves their head into a position where gravity moves the loose crystals, that canal sends a message to the brain that is an error.  The most commonly provoking movements are getting in or out of bed, rolling over in bed, bending, looking upward and quick head movements.

Because of the connections between our inner ears and our eye muscles, during the time the crystals are moving, the incorrect signal makes our eyes move in a way that makes it appear like the room is spinning.  In the most common form of BPPV, the spinning only lasts until the crystals stop moving because they’ve reached the lowest point in the canal, which takes less than 1 minute.  If things are spinning longer than 1 minute, it is either a rarer form of BPPV called cupulolithiasis, or it is a condition other than BPPV.  A well-trained Vestibular Rehabilitation Therapist, ideally using special goggles allowing for a magnified look at your eye movements, can help you determine whether or not you have BPPV, and if so, what form you’ve got and what canal the loose crystals have moved into.  This then determines the treatment maneuver that should be used.

How We Treat Bening Paroxysmal Positional Vertigo (BPPV)

To help sufferers of BPPV a vestibular rehabilitation professional uses techniques to locate the crystals that are out of place and employs maneuvers to reposition them back to the correct chamber with the help of gravity.  Typically after 1-3 visits peoples’ BPPV is corrected.   Sometimes people have some mild sensitivity to motion and/or some balance issues that persist after the BPPV is cleared, but these are typically easily remedied with some simple home exercises.

If you or anyone you know is experiencing dizziness or imbalance, feel free to contact us – we are here to help you!

5 Symptoms of Vestibular Disorders

Changes to Parts of the Inner Ear and Brain Controlling Balance Can Cause a Vestibular Disorder

Problems with balance and spatial orientation can include difficulty walking straight or turning a corner

According to the Vestibular Disorders Association if the vestibular system gets damaged or altered, a vestibular disorder can result. The vestibular system includes the parts of the inner ear and brain that control eye movements, perception of head movement and balance. Therefore, problems in any of these areas or pathways can create dizziness, unsteadiness or visual issues.

Besides dizziness or vertigo, five of the most common symptoms of a vestibular disorder are:

1. Imbalance or falling
2. A rocking sensation
3. A sense of exaggerated or "after-motion" when you move
4. Nausea or vomiting
5. Visually provoked dizziness (see below), or blurry/'jumpy' vision during head movement

Problems with balance and spatial orientation can include a tendency to touch or hold onto something when standing, difficulty maintaining straight posture, clumsiness or stumbling, and difficulty walking straight or turning a corner.

With visually provoked dizziness, there can be sensitivity to light or certain types of computer monitors, poor depth perception, trouble reading or watching TV, and discomfort in busy visual environments like crowds, traffic, or stores.

Some people with an inner ear disorder can experience these as well as other symptoms, and an inner ear disorder can even be present without any obvious symptoms at all. It is important to seek professional help and get a vestibular assessment if you are experiencing any of the issues noted above.

Contact us - we are here to help!

Academy of Otolaryngology Position Statement on Vestibular Rehabilitation

Vestibular Rehabilitation recommended as a beneficial treatment for dizziness and balance disorders

Vestibular Rehab Recognized as a Valid and Beneficial Intervention for Individuals with Dizziness and Disequilibrium

We wanted to let our readers know that leaders in the field of inner ear disorders have reaffirmed their recommendation of Vestibular Rehabilitation as a beneficial treatment for dizziness and balance disorders. BPPV is the cause of approximately 50% of dizziness in older adults ^[1].

Recently at the Academy of Otolaryngology – Head and Neck Surgery’s 2013 Annual Meeting, the American Academy of Otolaryngology revised a position statement regarding Vestibular Rehabilitation. Their position now states that:

 “Vestibular Rehabilitation, or Balance Retraining Therapy, is a scientifically based and clinically valid therapeutic modality for the treatment of persistent dizziness and postural instability due to incomplete compensation after peripheral vestibular or central nervous system injury.”

“Vestibular Rehabilitation is a valid form of therapy for dizziness and imbalance resulting from the medical or surgical treatment of vertigo disorders and for acute vertigo or persistent imbalance that may result from a variety of peripheral vestibular disorders.”

“Balance Retraining Therapy is also of significant benefit for fall prevention in the elderly patient who may suffer from multiple sensory and motor impairments or for those who have sensory disruption with moving visual information.”

Many sufferers of dizziness, vertigo and imbalance have benefitted from Vestibular Rehabilitation, and we know how important this treatment is to them. It is also a very positive sign when the work of Vestibular Rehabilitation professionals is declared clinically valid by the Ear, Nose and Throat medical community.

^[1] Fife TD et al. Practice parameter: therapies for BPPV (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurol. 2008;70:2067-2074.

What to Expect During Vestibular Assessment and Treatment

Dizziness or Balance Disorders Can Be Caused By a Number of Different Conditions

At LifeMark we give clients different tests to narrow down what may be contributing to their dizziness

There are many, many different conditions that can contribute to dizziness or balance disorders. To help narrow down a clinical diagnosis, at LifeMark we give clients a number of different tests and evaluations. One of the first steps of the assessment process is the Dizziness Inventory that we ask clients to download from the website and fill in before your first appointment. This questionnaire allows us to identify difficulties that you may be experiencing because of your dizziness or unsteadiness, and gives us some valuable clues about what conditions you might be dealing with.

Vestibular Assessment Includes Infrared Video-Analysis of Eye Movements

LifeMark's vestibular assessment is extensive and includes infrared video-analysis of eye movements, which provides information about the inner ear and its connections in the brain. Many of these eye movement clues cannot be detected in room light. Treatment can involve a combination of stationary and moving balance retraining, gaze stabilization to help you focus during head movement, training for motion sensitivity, and canalith resposition manoeuvres for BPPV; the results are often dramatic.

The balance retraining component is also effective for clients who don't necessarily have a vestibular problem, but have muscle and joint problems, brain-related disorders, sensation problems, or vision changes affecting their equilibrium. LifeMark is actively involved in collecting outcome measures to make sure what we do is making people better, and is committed to utilizing the most current, evidence-based tests and techniques in its training and treatment programs.

Vestibular Assessment Also Includes Motion Sensitivity Testing, Static and Dynamic Balance Testing and TMJ Testing

As part of your vestibular assessment we go through many of these tests, as determined by the nature of your symptoms:

• We take a thorough history
• We take your blood pressure both when standing up and lying down
• We perform motion sensitivity testing, scoring both the intensity and duration
• We perform static and dynamic balance tests, to compare to normative and fall risk data
• We test for TMJ (temporomandibular joint disorder) and cervical spine mobility
• We screen for any serious problems with the following:

1. Cranial nerve scan
2. Vertebral artery scan
3. Carotid pulse
4. Carebellar tests
5. Scans for upper motor neuron lesions
6. Ligamentous stability of the upper cervical spine

What is Vestibular Rehabilitation?

Vestibular Rehabilitation is a proven, research-based branch of physiotherapy where specific individualized techniques are used to maximize the brain's compensation for vestibular pathology, or where manoeuvres are done to correct mechanical dysfunctions in the vestibular apparatus.

What Can Cause the Problems?

Vestibular disorders can come from pathologies in any area of this complex system. They can be insidious ("out of the blue") or due to factors such as trauma (motor vehicle accidents, falls, contact sports, blows to the head), infections, aging, medications, brain-related problems, or secondary to other diseases or injuries. Symptoms can include dizziness, imbalance, blurry vision, motion sensitivity, nausea, poor concentration, muscle guarding/restriction of movement, decreased activity levels or social interaction, anxiety and depression.

Home-Based Exercise is Vital to Your Vestibular Treatment

Repeating Movements That Provoke Dizziness Will Help You Recover From It

Many sufferers of dizziness are surprised to find that not doing the movements that make you dizzy will actually delay your recovery in the case of vestibular problems. An exercise program that repeats the movements that provoke dizziness can train your brain to compensate and help you to overcome it.

At LifeMark Vestibular Rehabilitation, we educate our clients in specific techniques that gently reproduce the symptoms so that the brain can see the error signals enough to allow it to compensate for dizziness problems. The underlying problem may still be there, but the brain can do an excellent job processing signals in a different way so that you no longer feel the symptoms in many cases.

After an initial assessment, we provide individualized treatment plans with exercises to help your specific situation. Some ways that home-based exercises can maximize central nervous system compensation are:

• By reducing motion sensitivity (habituation)
• By improving static / dynamic balance
• By improving gaze stability (adaptation)

Just as figure skaters or ballet dancers learn to suppress and adapt to signals from the balance organs when they spin that would make the rest of us dizzy, we teach clients how to help the brain process this information so that the sensation of dizziness is lessened or removed altogether. When you are practicing the brief but specific exercises at home, we would typically see you once per week over a 4-6 week period, after which treatment is either complete or may be weaned down.

Exercise Helps the Brain Compensate For Vestibular Problems

Low-impact aerobics, Tai chi or a walking program can also improve general fitness levels, strengthen balance, and expose you to movements that help your brain compensate for vestibular problems. The Vestibular Disorders Association does not recommend doing vestibular exercises at home without a diagnosis and personal treatment plan from a vestibular specialist. We are here to help!

Contact us to find a vestibular specialist near you.