Welcome back to the Gates Brain Matter Minute!
Today, we are discussing Concussions and Eye-Movement Testing.
There is an old proverb that tells us “The eyes are the window to the soul.” While that may be accurate in various ways, in the world of functional neurology, we would say that the eyes are the window to the brain.
What can the movements your eye makes tell us about your brain?
Actually quite a bit!
Your eyes tell us so much that we dedicate a portion of your examination to eye movement tests!
There is a book called the Neurology of Eye Movements which has made eye movements to be the best understood aspects of brain function that exist.
To test and record these eye movements, we use a VNG, or a Videonystagmography. This equipment is typically used by Ear, Nose, and Throat doctors and audiologists to determine whether the cause of dizziness and vertigo lies in the inner ear. In the Functional Neurology world, however, we use this same equipment to determine damage sustained in the brain due to concussions and mild traumatic brain injuries.
A study was done by Dr. Ellis, a neurosurgeon in Canada, and his team. They studied 339 children, and performed VNG tests on them. 306 of these kids had suffered acute sports-related concussions and of them, 93 had post-concussion syndrome already. This group of young patients were displaying symptoms like nausea, dizziness, imbalance, or other post-concussive symptoms.
They found that when dysfunctional eye movements (vestibulo-ocular dysfunction) were seen on the VNG at their first appointment, the patient’s concussion recovery took twice as long and the patient was four times more likely to develop Post-Concussion Syndrome than post-concussed patients with normal eye movements.
So many people are told post-concussion that they are normal and healthy and it simply isn’t true, even when the scans show things to be normal.
We see this same phenomenon again noted in this study of 432 juvenile post concussive patients: abnormal balance, vestibulo-ocular reflexes and/or eye focus power (accommodative amplitude) predicts a prolonged recovery time.
In a newer study, they found that “standard clinical imaging fails to reliably detect” concussion damage to the cerebellum. Especially in the area of cerebellar peduncles. (Peduncle is pronounced like ped(estrian) uncle. Peduncle. Try to say this fast three times.)
Cerebellar peduncles connect the cerebellum to the brain stem. Concussions and mild traumatic brain injuries stretch these peduncles. This stretching results in damage to the cerebellum and that affects eye movements.
As we have discussed in prior newsletters, Diffusion Tensor Imaging is vastly helpful to show damages in the white matter of the brain and focuses largely on the supertemporal region, but DTI does not focus on the cerebellum. That is where the VNG tests come in. They show what is happening in the cerebellum where the DTI does not “see” well.
Like this last mentioned study, we can conclude then, that post-concussive symptoms are caused by damage to the cerebellum and there should be more investigation of the interrelationship between Diffusion Tensor Imaging scans and VNG results.
Often, your Doctor will run a neuro-psychological test. In these tests they study your memory, speed, attention, focus, creativity and flexibility. This test along with scans can be considered the totality of the post-concussive exam. In the functional neurology world however, these tests are only a piece of the complete neuro workup. Not the totality.
It is worth noting that sometimes post-concussive symptoms are associated with vascular dysfunction. A patient’s blood pressure may be too high or low, or they may have an elevated heart rate.
This makes sense when you remember that the base of the brainstem and cerebellum is where blood pressure is regulated.
Dizziness is generally known to be a problem in the inner ear but it is lesser known that it can also be a brain stem dysfunction issue.
In another study by Dr. Ellis, they share this diagram and make the argument that patients need vestibulo-ocular rehabilitation after a concussion. At Gates Brain Health, we absolutely agree with these findings.
Copyright © 2018 Ellis, Leddy, Cordingley and Willer.
Something that makes functional neurology really shine is the fact that they do rehabilitative therapies really well in each of these three areas: cervical spine, autonomic, and vestobulo-ocular.
A good functional neurologist can take the place of these countless other individual specialties!
If you are interested in seeing for yourself what Functional Neurology can do for you, give us a call! Your best health is waiting for you!
By: Gemma Ward. Based on Dr. Gate's video on Concussions and Eye Testing.