What’s the Cost of a Blockbuster Headache Drug?

Migraine headaches remain the most common neurological disorder in the world. While there are a number of drugs that can target a stop a migraine attack in its tracks, there are many patients who have been resistant to current medications and have to endure several migraine days or more each month.

In the last 2 years, a new drug has hit the market that is targeting a promising chemical pathway that is known to affect migraine patients. The drug is called Aimovig. It is an inject-able antibody that hits a compound called calcitonin gene-related peptide or CGRP. It’s the first drug of it’s kind targeting this pathway as migraine medications have historically targeted blood vessels as a source of migraine related pain.

Image result for cgrp and migraine
Image Source: Russo AF.
Calcitonin gene-related peptide (CGRP): a new target for migraine.
Annu Rev Pharmacol Toxicol. 2015
Link:
https://www.ncbi.nlm.nih.gov/pubmed/25340934

Scientists and clinicians have been excited about this drug for a little while as clinical trials have shown it to be well-tolerated with few side-effects. It’s also promising in the fact that it seems to help reduce migraine frequency so it might serve a preventative purpose.

Cost Benefit Analysis

In terms of results, clinical trials on patients suffering from 8 headache days per month had a reduction of 3.7 headache days per month compared to 1.8 days on placebo. It also showed that 50% of the patients taking the drug were able to cut their headache days in half compared to 26% on placebo. [Source]

The price for Aimovig comes out to $575/month with an annual bill of $6900 which you may need to take throughout your life.

It might seem like a lot, but for many patients with treatment resistant migraines, the cost is worth it to experience less days wasted by the suffering of a migraine.

The Value of Upper Cervical Care

We know that a subset of migraine patients do extremely well with upper cervical chiropractic care. If you talk to many doctors, they will often report that many of their patients will have greater than 50% reduction in their headache days, with some having an almost complete resolution.

This is because a large number of patients who have several migraines per month also have an upper cervical spine problems which are a known driver of migraines. A small study looking at the effects of NUCCA on migraine cases showed a significant reduction in migraine days and large improvements in migraine disability.

You can read the full paper here: Effect of Atlas Vertebrae Realignment in Subjects with Migraine: An Observational Pilot Study

Migraine patients under NUCCA care with headache days and quality of life improvements at 4 weeks and 8 weeks.
Migraine disability scores significantly improved in NUCCA patients from baseline to 12 weeks

This was a small study with no control group, so we can’t tell exactly how effective this is on a large scale. However, the experience seen by the patients in this study is a close reflection to what we see in clinical practice everyday.

Probably the most significant aspect of upper cervical care is the fact that it’s capable of producing these outcomes at significantly less expense. For many chronic migraine patients, getting them to the point where a reduction in their migraine days are stable can happen within 8-12 weeks.

Once they’re there, then patients are usually ready for periodic visits to maintain their atlas alignment. While costs vary, the average migraine patient in our clinic might spend $1500-1800 in their first year with us, and a few hundred dollars in subsequent years.

A large difference from $6900 a year on going.

The Pyramid of Plasticity: Organizing and Prioritizing Brain Functionality

How do we organize such a diverse array of functions for the brain? When someone has a #concussion, it’s rarely just one part of the brain that gets injured. The interconnectedness of the brain means that damage to one part means multiple functions will deteriorate.

So when someone comes in and they are feeling dizzy, their cognition is foggy, they have headaches, their heart is racing, how do we decide how to prioritize their care?

A concept developed by Dr. Matt Antonucci of Plasticity Brain Centers (@brainguru) helps to prioritize different levels of brain function. The good thing is that the areas of function seem to correlate with the anatomical organization of the brain.

The functional organization of the brain closely mirrors the anatomic organization of the brain. The bottom areas are primal and necessary for survival, and higher areas allow for stronger adaptability.

In many cases the areas of the brain that responsible for survival are lower in the brainstem, where as the areas concerned with higher level thought processes are high in the cortex.

If your brain can’t control blood flow very well for survival, it is certainly not going to care if you can do complex mathematics.

So when we assess a patient, we have to prioritize the systems that will restore function at the bottom of the pyramid, because many of the systems on the top depend on the bottom portions working.

What does this look like practically?

If a patient had a concussion and their chief complaint is brain fog, many people will want to target their cognitive areas of the brain. But what if they have brain fog because they have undiagnosed #dysautonomia causing an erratic heart rate?

We don’t fully have the answers without a good exam, and every patient’s experience is unique, but this can give people a strong starting point to organize their recovery after a brain injury.

Concussion and Eye Movement Series Part 2: Smooth Pursuits

Smooth pursuit eye movements are the ones we use to follow a moving object without moving our heads.

We take it for granted how simple this is, but this eye movement requires the coordination of several brain regions including the parietal lobe, temporal lobe, cerebellum, and multiple brain stem nuclei.

Image result for smooth pursuits neural substrates

Here’s a ridiculously complex graphic about the brain regions involved in smooth pursuits. It’s insane what goes on in the brain to accomplish such a seemingly simple task. A concussion can disrupt any part of this pathway, or multiple parts depending on the nature of the injury.

It requires us to:

  • Predict an object’s velocity – Correct for quick changes in direction
  • Maintain focus and attention
  • Ignore new and interesting background stimuli

After we hit our heads, any one of these areas can be affected which means different elements of smooth pursuit can become compromised.

Brain injuries can cause our pursuits to become slow, get pulled off target, delay reaction time, or even ignore parts of your visual field.

This can cause problems for athletes who need elite visual tracking abilities like baseball players, wide receivers, and hockey players. But some important notes:

  • Smooth pursuit deficits can be completely asymptomtic
  • Having poor pursuits isn’t useful diagnostically because many problems including aging can cause bad pursuits
  • Smooth pursuit testing needs to be taken on the context of other exam findings to localize the problem in the brain and determine the best method of rehabilitation

While it doesn’t tell us much diagnostically, it can be used as a metric to see how well your brain is responding to #neurorehabilitation.

Concussion and Eye Movement Series Part 1: Anti-Saccades

Eye movements have become an important diagnostic for patients with neurological disease and dysfunction. It’s one of the reasons we have invested into using extremely sophisticated eye tracking technology so that we can asses and manage patients effectively with traumatic brain injuries.

This will be the first in a series of posts about eye movements that are commonly affected with concussion. The first eye movement we’ll discuss is called anti-saccades.

What’s A Saccade?

In order to know what an anti-saccade is, we have to know what a regular saccade is. A saccade is a fast eye movement that takes your eyes from one target to another. Saccades are the eye movements we use to explore the world around us. They are also eye movements that react very quickly to new things in our environment. These can be a movement in the background, a flashing light, a loud noise, or a touch on our skin.

When we perceive there’s something in our environment that needs our attention, we use saccades almost like a reflex to direct our brain’s attention toward that new stimulus.

What’s an Anti-Saccade

An anti-saccade is a concept developed to see if someone can consciously inhibit a desire to look at something new. During an anti-saccade, we would have you fixate on a central target, and when a new target comes up, we ask you to move your eyes in a spot opposite to where the new target appeared.

The anti-saccade test


Antisaccades require our brain 🧠 to ignore a new stimulus and to create a plan to move the eyes 👀 to a mirror location.

This task requires higher level brain activity because our brains are wired to look at new stimuli. Specifically it requires a functioning prefrontal cortex (PFC).

In patients with concussion, their ability to perform Anti-saccades is compromised where they make frequent eye movements towards the new target, or they take a long time to move their eyes in the opposite direction. This indicates problems with a function called response inhibition. It’s the ability for our brain to stop doing something we don’t want it to do.

This requires a part of our brain called the pre-frontal cortex. Specifically, the dorsolateral prefrontal cortex. We’ll just call it the PFC for short. The PFC is what allows us to inhibit a desire to do something that may be inappropriate.

We need our PFC to stop ourselves from making inappropriate reactions. It’s one of the main differences between an adult brain and a child’s brain is that our PFC keeps us from having meltdowns when something goes wrong.

Parents of toddlers, you guys know what I’m talking about.


So when we take a hit to the head and our PFC goes down, we can have responses that aren’t appropriate. This might mean an emotional outburst, or problems controlling wreckless behavior like uncontrolled gambling. A viable PFC is critical for that and for keeping our bodies from over reacting to stress.

This provides us a meaningful way to assess PFC activity and gives us an way to improve PFC activity using eye movement therapies.

Not only can anti-saccades be used to assess the functionality of someone’s PFC. It can play a role in helping someone rehabilitate their PFC or other aspects of the brain connected to it.

Working on Your Curves: Long Term Outcomes From Fixing Military Neck

I’ll admit that I’ve gone back and forth on the importance of cervical curves in my career. When I was in chiropractic school I was adamant about the importance of cervical curves and how the loss of a curve could affect the progression of spinal arthritis.

Then once I was in practice for a few years, I saw that most neck curves wouldn’t really change very much. Despite the fact that it didn’t change, I’d see really great changes and improvements of many of my patients, so I assumed that it is a nice feature, but probably not necessary to resolving a complaint. You can read some of my previous thoughts on cervical curves here:

I Have Military Neck: Now What?

So What Has Changed my Mind?

I still stand by my previous writings and say that having a proper neck curvature is a really good and positive thing, but you can still get really great results with most secondary conditions even if the neck curve doesn’t come back.

However, I have started to come around on the importance of having a proper neck curvature for the health of the human brain and nervous system. So what changed my mind?

Here are three pretty recent studies looking at the impact that cervical curve changes have on dizziness and cerebral blood flow.

Increase in cerebral blood flow indicated by increased cerebral arterial area and pixel intensity on brain magnetic resonance angiogram following correction of cervical lordosis

The first paper is a study that looked at consecutive patients getting imaging of the arteries going into the brain. Magnetic resonance angiography (MRA) measured the intensity of blood flow with the neck in patients with a straight or military neck pattern. The patients were then placed on a foam orthotic to produce a curve in the neck and a new MRA was taken with the neck in a curved position.

Before and after changes in blood flow to the brain using a device to improve cervical curve.

The patients’ MRA scans showed significant improvements in blood flow in the brain when they were lying on the orthotic with an improved cervical curve! The interesting thing is that it’s been known for years that a loss of cervical curve was associated with decreased blood flow in the brain, but there was no evidence showing that improving the curve would change blood flow. Now there is.

The effect of normalizing the sagittal cervical configuration on dizziness, neck pain, and cervicocephalic kinesthetic sensibility: a 1-year randomized controlled study.

While the previous paper is interesting, it’s limited by the small sample size and lack of controls. It was also a proof of concept study, and not one where an intervention was performed and tested to see if it made a difference long term. However, it may help explain why patients can get significant improvement in pain and dizziness.

This next paper features a randomized clinical trial of cervical curve correction along with cervical manual therapies compared to manual therapy alone for cervical dizziness.

The study looked at the results for patients with neck pain and dizziness for short term improvement at 10 weeks, and to see if they sustained improvement at a 1 year follow-up. The results are below.

Differences in patients with cervical dizziness at 10 weeks and 1 year. Changes after 10 weeks were similar to regular physical therapy, but the changes were hugely different at 1 year when there was an improved curve in the neck

The chart shows that the patients who were in the cervical curve correction group had significant improvements in head posture and curvature at 10 weeks, but the scores in pain and dizziness were pretty similar for both groups. Both groups got better, but they had similar improvements.

However, the changes at 1 year were impressive, and highlighted in red. While the control group had some regression into neck pain and dizziness, the cervical curve group maintained their symptomatic improvement much better. The mean improvements for both groups all crushed statistical significance, and the mean difference of the Dizziness Handicap Inventory (DHI) was by almost a whopping 30 points. That’s massive!

Does improvement towards a normal cervical sagittal configuration aid in the management of cervical myofascial pain syndrome: a 1- year randomized controlled trial.

A similar study was published on patients with persistent neck pain where physical manual therapy was compared to manual therapy and curve correction.

Just like the study involving dizziness, this paper on neck pain showed that both groups had similar improvements in scores on the Neck Pain Disability Index (NDI).

Changes in neck pain with manual thearpy and exercise alone vs manual therapy, exercise, and cervical curve restoration. Cervical curve patients were a little btter at 10 weeks, but were much better at 1 year follow up!

Again, like in the previous study, the 1-year follow-up is where things got interesting. The group that had treatment to improve their cervical curve had a much stronger ability to maintain their improvements in neck pain, while the control group started to return to their original pain scores. This was also largely statistically significant.

Long-Term Improvements Matter

So the big thing that changed my mind is that there is a growing body of work that supports the idea that creating structural changes in your cervical curve seem to help improve long term outcomes.

So while I still believe you can get significant improvement with or without a curve in your neck, your chances of maintaining your results over time seem to increase a LOT when you rehabilitate that curve.

Then you have the possible added benefit of improved blood flow to your brain, and that provides a potential bonus of better brain health.

Why Weak Muscles Are NOT the Reason Your Back Went Out

I’m a mega-proponent of strength training. It’s a major part of my life and it’s something I’ve always encouraged for my patients, family, and friends as a way to dramatically improve someone’s life.

That being said, strength training is an integral part of the treatment and prevention of musculoskeletal pain. There’s probably no condition in the world that has been widely attributed to a strength deficiency than lower back pain.

Got back pain? Must be those

  • Weak glutes
  • Weak transverse abdominus
  • Weak multifidi
  • Etc, etc

So now we have an entire world of fitness focused on preventing lower back pain by developing really intricate exercises to strengthen an unending list of muscles connected to the back.

Are Weak Back Muscles Really The Cause of So Much Back Pain?

I do believe that being sedentary, and the general weakness and de-conditioning associated with a lack of movement does put people at risk for low back issues. After all, being sedentary and de-conditioned is basically a risk for just about everything.

However, I do think that we need to re-evaluate why so many active and relatively strong people throw their backs out doing really slight movements.

What do I mean by that?

For many of the patients that have come to my office for chronic back pain, their stories don’t usually feature an attempt to lift something that was extraordinarily heavy. It’s generally things like:

  • I was reaching to grab my phone when I heard a pop
  • I was rolling out of bed when I felt something seize up
  • I was bending over to pick up a pillow when my back went out

Plus these people aren’t necessarily weak. These are people who can deadlift 400+ lbs or spend their day as construction workers lifting heavy things every day. I can promise you that these individuals did not have weak glutes.

So what might have happened?

The Principle of Coordination

All of the strength in the world is useless when the body is not prepared to make use of it.

Have you ever been to a bowling alley and picked up the wrong ball by accident? It’s a strange feeling. You may be accustomed to picking up a 9 lb ball, but the ball next to it was the same same color and shape but it weighed 14 lbs.

So you went to pick the ball up with the amount of force that you expected to easily lift the 9 lb ball, but your arm moves slower and you have to catch yourself for a second before reaching down and grabbing the correct ball.

Even though you are plenty strong enough to lift a 15 lb object without any problems, you were thrown off because your brain made a calculation wasn’t appropriate for the lift it was about to perform.

This takes a coordinated effort for your brain to tell your muscles to use the correct amount of force with the right timing in order to make lifting an object feel more effortless. It’s a really neat system when it works properly!

But if you didn’t know how much something weighed, and you went in without expectation, you would probably take a conscious effort to over-prepare your body to lift an object up so you wouldn’t be caught off guard. Your brain has plans and contingency plans for when it encouters an unknown situation.

So what does this have to do with your bad back? Your back is different from most of the other muscles in your body in that it is a muscle group that is almost always on. Your arm and shoulders don’t get used unless you need to perform a task. Your legs are always on when you’re standing, but they can be rested when you are sitting. Your spinal muscles only get a rest if you are laying down, which is a small chunk of the day for most.

Control of spinal movement is dictated by an intricate control system between the brain receiving feedback from the spinal muscles and joints, and commands to control it

This is an important concept because our spine has to move for just about everything. Even when you are lifting your arm or your leg, your brain is sending messages to your spinal muscles on how to move your spine to accurately perform an arm/leg movement.

When Coordination Fails

So we know that the spine is always on, and even when you are just trying to move any body part alone, your brain is still getting your spine prepared to brace or move in concert with other limb movements.

There is a lot of coordination that has to happen with this, and sometimes there are just moments in time where coordination will fail, and injury can occur in those small windows.

It wasn’t just an issue of being weak. It was an issue of timing that one part of your muscular system didn’t create a good enough response to protect the parts of your spine that may generate pain.

This doesn’t mean that you’re broken. It doesn’t mean that you need fixing. It means that when you’re active and putting your body under a steady dose of mechanical stress through exercise, sometimes things may get hurt.

It’s okay! Your body can heal, get better, and improve with time, especially when you have good alignment, flexibility, mobility, and appropriate rest.

Can Coordination Improve?

There are a number of things people can do to improve the coordination of your spine and nervous system. It involves making your spine more adaptable. So how can we improve our adaptability?

  • Respect your alignment and biomechanics. You don’t have to be obsessed about it, but dysfunctional spinal joints from structural shifting of the spine can decrease neurological coordination
  • Expose your body to different loading patterns. Perfect form in the gym is great, but your brain needs exposure to variation in movement so it knows how to deal with it in the future. Mix up your lifting and movement strategies
  • Train on different surfaces – You won’t always be on a nice flat gym surface when you have to lift something up. Perform movements and exercise on different surfaces to allow for your nervous system to adapt
  • Do reaction time training – reaction time training or rhythmic movements can train your body to work in different patterns and rhythms.

Why Am I So Off Balance?

A persistent feeling of being off balance can be one of the most disabling feelings a patient can have. Many patients who suffer with balance issues don’t receive proper examination and diagnosis, so they are left without many answers for treatment besides generic anti-nausea medications or herbal remedies like ginger.

In order to best take care of people with persistent balance issues, we have to understand why balance gets disrupted to begin with.

Normal Balance

We tend to think of balance as a function of leg muscles and joints, so we think of balance training as just standing on a Bosu ball or standing on one leg. We take balance fore granted because when it works well, we hardly have to think about it.

Truthfully, balance is the product of some complex calculations made by your brain based on 3 major senses. These senses are:

  • Vision from your eyes
  • Proprioception from your muscles, joints, and ligaments
  • Vestibular from the fluids in your inner ear

Your brain takes information from these 3 senses and compares it to information stored in your memory, experience, and context of your current situation and develops a strategy for how your muscles should fire to keep your body up right. It’s really pretty amazing when you think about all the moving pieces involved.

Even more unique is the fact that as far as mammals go, there aren’t too may of us that stand upright on 2 feet. Most of the animal kingdom stands on 4 legs so our brains had to develop differently from an evolutionary perspective than our mammal ancestors. The time it takes for our brains to develop this skill is one of the reasons why some mammals like start walking and moving right away, while humans take about a year to get to our normal mode of transport (standing/walking).

Being a father of a 1 year old has taught me a lot about how we develop balance by watching my little one learn to navigate that skill.

So you might think that your brain relies on all of these senses equally under normal circumstances, but in reality these senses are weighted differently. Here’s the breakdown:

Under normal circumstances, your brain prioritizes information from your joint and muscular system

So normally, an adult with healthy balance does rely on their muscles and joints (particularly in the legs and feet) or your sense of balance. That’s probably why things like weight training, yoga, bosu ball exercises, and more can strengthen the balance of people with normal functioning systems. All of those things really challenge and promote neural pathways to enhance your body position sense.

But what happens when our senses starts to decline?

Balance Fails: When Senses Break, When the Calculator Breaks

If one of our senses starts to struggle, your brain has to weigh your senses differently. We can actually test this in our office by performing balance tests in different sensory circumstances. For example, if we have you stand on an unstable surface, your brain puts more emphasis on your inner ear and vision because the unstable surface is giving your brain constantly changing information that makes it hard to rely on.

The good news is that your brain is great at compensating when one sense goes down. Losing one inner ear to infection is a problem that most people can recover from and regain normal function. Usually patients that still suffer from balance issues after loss of one inner ear respond really well with vestibular rehabilitation to re-compensate the patient’s brain.

The bad news is that when multiple senses aren’t working well, it makes it really hard to make up the difference. Losing both inner ear systems from infection or Meniere’s can permanently alter your balance. The same thing can be said for having neuropathy in both feet or having a ocular misalignment in both eyes. For these types of issues, people can only hope to compensate as best as they can for permanent deficiencies.

The other possibility is that the brain itself takes an injury like a concussion or stroke disrupt the brain’s ability to make calculations. This is especially true for injuries related to the brain stem or cerebellum which are major centers for balance control.

The good news is that many of these problems can be improved with chiropractic and neurorehabilitation.

Targeting the Correct Body Parts

We often see a lot of patients with movement and balance issues after they’ve been to several other doctors and specialists. One potential pitfall is that many specialists have one area of focus which creates a conundrum commonly seen in medicine.

When you have a hammer, and you’re great at hammering, everything looks like a nail

There was a point in my practice where every balance problem that came in to my office was a problem in the neck, and we did really well with most patients!

We still address the neck as a primary problem in most patients, but working with more and more patients with balance issues and dizziness, we have taken a step back so we can see the whole picture.

Having a new perspective on patients by looking at balance as a function of the brain has helped us improve outcomes with challenging balance issues.

The first step is performing a thorough exam, not just on the neck, but on the visual, vestibular, and somatosensory system to identify how this problem might be addressed best with a personalized program of neurological rehabilitation.

How to Tell if Migraines are Coming from Your Neck

A recent systematic review in the prominent journal Headache showed that spinal manipulation could have an effect on headache days and pain intensity in patients with migraine headaches. While this is old news to many practicing chiropractors, this is one of the first instances that a major headache journal has acknowledged that manipulation could have a legitimate positive effect in patients suffering with migraines.

When it comes to migraine headaches and chiropractic, there’s a big gap in knowledge between what clinicians see in the field everyday and what the published literature says about our effectiveness. The published literature has generally shown that chiropractic might be good for tension headaches, but clinical trials on migraines have suggested that it’s not significantly better than placebo.

On the other side, patients with migraine headaches are often our most successful cases in upper cervical chiropractic. It’s not even that we tend to be just a little bit successful with chronic migraines patients, many of us expect these 85-90% of these patients to get a lot better in a matter of weeks. It’s usually not the easy migraine patient that comes into our offices either. Typically people don’t find an upper cervical chiropractor until they’ve tried a wide variety of treatments and medications.

So what gives? Why is there such a gap between private practice and published research?

I believe there’s 2 main reasons:

  1. Most spinal manipulations done in research have used non-specific contact, general manipulation of the neck, where as upper cervical techniques use a very precise and targeted force to one part of the neck. To date, there are no clinical trials investigating migraine headache and upper cervical work. (But this is a soap box for another day)
  2. Previous clinical trials haven’t done a great job in identifying patients that have the signs of a cervical spine dysfunction.

Identifying Cervical Spine Dysfunction in Migraine Patients

One of the most important things we do during a Complimentary Consultation is to figure out if you’re a good candidate to respond to the type of chiropractic we perform in our office.

While getting your spine corrected is healthy in of itself and anyone could benefit from it, I only take on cases that I believe can significantly improve your quality of life. In order to do that, I always screen patients to make sure that I am going to have a high likelihood of success in helping you reach your goal.

In the case of a migraine patient, we are looking for clues that tell us that your migraine symptoms are primarily being generated by the neck. Migraines can have different causes:

  • Some have a biochemical issue in the brain and may benefit from something like a ketogenic diet.
  • Some have a higher hormone component and need to be addressed by modifying the endocrine system
  • And many have a major cervical spine component

How can you tell if it’s coming from the neck? Beyond just looking for neck pain, here are some major clues that have been identified in migraine research:

  1. Worse ability to turn their upper neck side to side – A test of upper neck rotation called the flexion rotation test has been shown to be more asymetrical in some migraine patients compared to normal controls [Source]
  2. Decreased sensitivity to 2 point discrimination in the upper neck – A study showed that migraine patients have decreased ability to differentiate between 2 points when applied to their neck. [Source]
  3. Increased pain and tenderness in the upper neck – patients with cervical spine issues show increased tenderness to touch in their upper neck. It becomes even more significant if pressing on a sensitive area recreates the pattern of head pain [Source]

Can The Neck Be Fixed?

A 2015 study looked at the effects of an atlas realignment in patients with chronic migraine headaches. The study showed that a gentle correction to the upper neck showed significant improvements in headache days and quality of life in migraine patients over the course of 8 weeks.

We rely on 3 big factors for improving the neck.

  1. We need to see a structural change in the biomechanical alignment of the neck after an atlas correction.
  2. We want to see a global change in posture in response to correcting the alignment of the neck
  3. We want to see a change in the tenderness of the muscles and nerves stemming from the upper neck. Just as we saw that those tender spots predicted migraine, when we feel those tender points subside right after a correction, it’s a strong marker that we are on the right track.

While we can’t fix everyone, there’s a large segment of the migraine population that would do well with this form of care, but we have to make sure we identify the right candidates.

New Study Examines the Effect of Chiropractic on Patients with Previous Stroke

The effects of a single session of chiropractic care on strength, cortical drive, and spinal excitability in stroke patients.

Scientific Reports 2019

Holt K, Niazi IK, Nedegaard RW, et al.

Abstract
Full Text

Summary

A research team based out of the New Zealand College of Chiropractic who have been publishing a great deal on the neurophysiologic impact of chiropractic on the brain did an investigation on the impact of chiropractic adjustments on patients who have previously suffered a stroke.

The study was set up as a randomized controlled crossover trial of 12 patients with a previous history of stroke. For the first week, half the patients received an adjustment while the other half had a control maneuver of just moving the body around. Seven days later, the groups switched with the control group getting an adjustment and the intervention group getting a control.

The authors tested patients who suffered weakness in their ability to plantar flex post stroke and tested their strength on plantar flexion pre and post adjustment.

They also wanted to know if there were increases in strength, were they likely tied to a local spinal cord mechanism, or did the strength change come from the brain. To do that, they used electrodiagnostic testing to measure things called the H-Reflex and the V-Wave.

The H-reflex uses an electrical stimulation of a peripheral nerve (the tibial nerve in this case) during a sub-maximal contraction to measure excitability in the spinal motorneuron pools (influenced at the spinal cord level)

The V-Wave uses electrical stimulation during maximal contraction to measure recruitment of additional neuronal pools which is an indicator of cortical drive (influenced by the brain)

If you want to get into the weeds on these tests, you can read this paper here.

Results
There were large and significant changes in maximum contraction of plantar flexion post adjustment while the control group showed a decrease in strength.

As far as the electrical diagnostic testing, the chiropractic group showed large and significant changes in the V-wave indicating that the strength change was likely from a brain mechanism (cortical drive).

For the H-Reflex slight change in the adjustment group that was not significant. There was also a slight decrease in V-wave change in the control group that was also not significant.

Dizziness and the Cervical Spine: Beyond Cervicogenic Dizziness

Read Time: [6 minutes]

Outline:

The cervical spine has been a known source of dizziness since the 1950’s with a classification as cervical vertigo. While the true spinning sensation of vertigo is not common with cervical spine issues, a feeling of imbalance, disorientation, light headedness, swaying, and unsteadiness have all been linked to problems in the cervical spine, especially the craniocervical junction.

Cervicogenic vertigo has a contentious history as a legitimate clinical entity. This stems from the fact that cervicogenic vertigo has no distinct biomarker and remains a diagnosis of exclusion; a leftover diagnosis when a more obvious inner ear cause doesn’t exist.

Cervicogenic vertigo may or may not exist as it’s own unique clinical entity, but there’s little doubt that the cervical spine plays a key role in balance and equilibrium. In this article, we’ll talk about how a dysfunctional cervical spine can be causing dizziness, and how cervical spine interventions can be a useful therapeutic option for people with dizziness disorders of many types.

The Anatomy of Cervicogenic Dizziness

While the diagnosis of cervicogenic vertigo has been contentious, the anatomical connections linking the cervical spine to symptoms of dizziness are not.

Neck Muscles, Ligaments, and Joint Receptors

The neck is loaded with receptors that help the brain know where the head is in relation to the body. These receptors come from the small suboccipital muscles, the cervical discs, the cervical joints, and the cervical ligaments. The receptors from the suboccipital muscles in particular have an unusual amount of density when compared to the rest of the spine [Source]. When you move your neck, these receptors help to control how fast and how far you move your neck. They are also receptors that are very active even if your head isn’t moving because we spend most of our time with our head up fighting gravity. All of these signals are transmitted to the brain which has to make constant decisions about where to put the head next.

Image result for upper cervical spine ligaments and muscles

When you have an injury like a whiplash or head trauma, the muscles and ligaments of the neck are susceptible to injury, and that injury takes away one of the methods that your brain uses to keep track of the head. If your brain can’t tell where your head is in space, then dizziness and a sense of imbalance is the result.

Cerebellum and Vestibular Nuclei

The cerebellum and vestibular nuclei are 2 really important parts of the brain that play a role in dizziness and balance problems originating from the neck.

The vestibular nuclei is the routing center for the signals traveling from your inner ear through the vestibular nerve. The primary job of the vestibular nuclei is to take the information coming from your ears and to calculate where the head is in space and to move the eyes appropriately in response to these signals. While the bulk of the input into the vestibular nuclei is coming from the ears, the vestibular nucleus also receives afferents from the cerebral cortex, visual centers, spinal cord, and cerebellum. It takes in all of this information and calculates where the head is in space based on what you see (visual), head direction (inner ear), and proprioception (muscle and joint activity).

Image result for cerebellum and vestibular nuclei

The cerebellum is generally thought of as a subdivision of the brain that aids in coordination of muscle movements. However, the cerebellum has an large chunks of real estate devoted to eye movements and modulation of the vestibulo-ocular response. The cerebellum also plays a role in how the vestibular system impacts the spinal muscles via the vestibulospinal tract.

These regions of the brain are important because the same muscles, ligaments, and joint receptors we discussed earlier have direct and indirect connections to the vesibular nuclei and the cerebellum.

The Vertebral Artery

The vertebral artery passes through the transverse foramina in the cervical spine. At the level of C1 and C2, the vertebral artery takes on a more tortuous path into the skull to supply the brain stem and cerebellum with oxygen. Most clinicians think of the vertebral artery as a potential source for arterial dissection that can cause stroke. However, there are documented cases of transient vertebrobasilar insufficiency caused by rotation of the neck. This syndrome has been named Bow-Hunter Syndrome or rotational vertebral artery vertigo (RVAO). [Source]

Studies have shown that decreases in blood flow from the vertebral artery can cause transient ischemia through the vertebral artery when the neck is turned in rotation. It’s not known whether the ischemia is affecting the brain stem/cerebellum, or if the ischemia is hitting the labyrinthe itself because of the way the artery branches out toward the peripheral vestibular apparatus.

Beyond Cervicogenic Dizziness

Therapies for the cervical spine can make an impact on cervicogenic dizziness. These therapies can commonly include cervical exercises, osteopathic manipulation, upper cervical chiropractic approaches, and other manual therapy techniques. The use of these modalities has largely been associated in patients who have reported dizziness following a trauma to the neck such as whiplash disorder [Source].

Is there a role to play for cervical spine-based therapies for other causes of dizziness and imbalance?

While there’s limited evidence to pull from, there are numerous anecdotes and case reports of patients with motion sickness, Meniere’s-like illness, and vestibular migraine showing improved outcomes while receiving care focused on addressing cervical spine dysfunction.

Let me be clear, I have no supporting research to support what I’m going to say next. These are just observations from 8 years of working with dizzy patients.

Many patients with feelings of dizziness but do not have full peripheral vestibular loss likely have problems of central processing of sensory information. Plastic changes in the central nervous system that can promote a sense of dizziness can include:

  • Inapporpriate Sensory re-weighting for balance
  • Inappropriate afferentation into the vestibular nuclei and cerebellum
  • Anxiety related to pathologies or activities that promote dizziness
  • Decreased cellular activity in key sensory areas of the brain due to disrupted hemo/hydrodynamics

Simplified flowchart showing the way sensory information contributes to balance

By understanding some of the interconnected nature of the senses that produce a feeling of balance, we can leverage treatments to create neuroplastic changes in the central nervous system that may help a person adapt when vestibular function is compromised.

When it comes to dizziness, there are so many anatomical players and varying degrees of compromise, we can’t rely on one thing to fix all types of dizziness. By using the cervical spine to help stimulate the proprioceptive system, we might be able to help some patients compensate with a deficit where they weren’t able to before. We may also be removing one extra stressor to the balance system that was preventing the body from compensating appropriately.