Exercise as it relates to Disease/Post-Concussion Syndrome; prescribing exercise to reduce symptoms

This is a review and critque of the article authored by John Leddy et. al. in 2013 titled: Exercise treatment for postconcussion syndrome: a pilot study of changes in functional magnetic resonance imaging activation, physiology, and symptoms.

What is the background to this research?
For most people concussion symptoms alleviate within 10 – 14 days but in some cases, symptoms persist for months. Post-Concussion Syndrome (PCS) does not have a definitive test but is characterised as the persistence of symptoms caused by concussion longer than the expected recovery time; for many physicians this means any symptoms lasting longer than 2 weeks can be diagnosed with PCS.

Few interventions are commonly recommended. Rest is still the most common recommendation, with some pharmacological and therapy options. These interventions are focussed on relieving symptoms, and not treating the underlying condition. The particular pilot study being reviewed in this article is one of the early studies in this area. The body has research on this topic has since been built on by later studies including a number of randomised control trials, culminating in a literature review which was published in 2019.

Where is the research from?
This pilot study was published in the journal of head trauma rehabilitation. Its editor-in-chief is John D. Corrigan, PhD, ABPP. Dr Corrigan’s research has focused on long-term patient outcomes from traumatic brain injury based at the Ohio State college of medicine. The article itself had John J. Leddy, MD, as its lead author who is considered an expert in concussion and post-Concussion syndrome based at the University at Buffalo. Dr Leddy, along with Dr Willer (a co-author) are responsible for the development of the Buffalo Concussion Treadmill test (BCTT).

The article was funded by the University at Buffalo, the Robert Rich family foundation, and the buffalo sabres foundation.

The authors declared no conflicts of interest.

What kind of research was this?
This is a pilot study, where they are looking for trends in a small population in order to direct future research. This pilot study was done with a quasi-experimental design, or a control trial that wasn’t randomised. Three groups were formed made up of 4 participants each. Being a pilot study with just 4 participants in each group means we cannot extrapolate the results to the general population, but it can affect the direction we take future research in the area. The three groups made up the stretching ‘placebo’ group, the exercise ‘intervention’ group, who all had PCS, and the control group, who were all healthy. Participants were not aware whether the stretching or exercise group was expected to perform better.

What did the research involve?
The three groups were all as similar as possible in terms of age and athletic ability. The population size made variability in gender unavoidable.

The number of symptoms each participant was experiencing was recorded using a validated diagnostic prompt consisting of 22 possible symptoms (excluding the control group, who had no symptoms). All participants with PCS then conducted the BCTT (established by the same authors in an earlier study) to establish the heart rate at which symptoms became worse, which was recorded.

All participants involved in the study performed a simple math task while connected to a functional MRI (fMRI) machine, which measures the changes in blood flow inside the brain (Cerebral blood flow, CBF). Cerebral blood flow has been shown to be altered in people who’ve had a concussion, and is effected by aerobic exercise. Participants were asked to answer the math questions as quickly and accurately as possible while the fMRI monitored their cerebral blood flow. differences in cerebral blood flow between partiicpants in the control group and those with PCS were noted.

Each group then continued with their intervention, for the exercise group this was a controlled progressive aerobic exercise program at 80% of the heart rate established in the BCTT for 20 minutes, 6 days a week. The participants were considered ready for final testing once they were able to exercise up to the age-predicted maximum heart rate without symptoms getting any worse.

The stretching group was given a booklet that explained in both written and figure format a standardised and gradually progressive 12-week low impact breathing and stretching program designed at the University at Buffalo. Participants stretched for 20 minutes a day, 6 days per week and wore heart rate monitors to ensure their heart rate did not elevate to their heart rate threshold level established in the BCTT.

Following their intervention, they repeated the fMRI and BCTT to establish any differences between pre and post intervention.

What were the basic results?
Participants performance in the speed and accuracy of their answers to the math questions was unaffected, and not significantly different between any group, or between pre and post intervention.

Pre intervention participants who had PCS did show differences in their CBF during the fMRI compared to the healthy control group. Post interventions the exercise group had big changes in their cerebral blood flow and were no longer significantly different from the healthy control. The stretching group had no change in cerebral blood flow from pre to post intervention.

During the BCTT post intervention, the exercise group were able to exercise to greater then 90% of their max age-predicted heart rate, the stretching group had no significant differences in heart rate achieved Post intervention, compared with pre intervention.

The Exercise group went from an average of 17.5 symptoms to just 2 following their intervention. The stretching group only managed to fall from 19 symptoms to 15.

What conclusions can we take from this research?
This study, despite being a pilot study, shows that exercise appears to be a valid and safe option for the treatment of PCS, therefore further research with larger populations are warranted. Since this pilot was released a number of further studies have been done, with similar promising results.

Further research should be done on the direct cause of PCS symptoms, and if changes to blood flow in the brain is one the main contributing factors. Further research should be done on how exercise effects and these changes in PCS patients to discover whether exercise is the first treatment that improves the underlying cause and not just management of symptoms.

As the authors of this study also developed the BCTT, more research should be done into whether this is the best practice for establishing heart rate thresholds for the prescription of exercise, the authors may have bias towards using this methodolgy, which needs to be considered.

Practical advice:
The ongoing research in this area should be closely monitored so the best practice for treatment can be implemented siftly, Exercise Physiologists should be employed by allied health teams to safely prescribe and control the dose of exercise in a treatment plan. Exercise physiologists who work with concussion patients frequently and have the resources to do so, should seek training on the BCTT and educate themselves on the protocols of its use.

Anyone who is diagnosed with concussion or PCS should continue to work with their GP, physiotherapist or exercise physiologists and follow their recommendations and advice.

Further information/resources:
General interest:

Coping with Post-Concussion Syndrome - Concussion foundation

Paddy McCartin Opens Up On His Physical & Emotional Struggles With Concussion

Stevie Ward - Living with concussion (26min Documentary)

Stevie Ward - Living with concussion (Sky Sports article on above documentary)

Academic work on this topic:

John Leddy's work on concussion

BUFFALO CONCUSSION TREADMILL TEST (BCTT) – INSTRUCTION MANUAL