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Journal Club Review: Use of Exercise to Reduce Chronic Post-Concussion Symptoms in Athletes

                A Preliminary Study of Subsymptom Threshold Exercise Training for Refractory Post-Concussion Syndrome.  Leddy JJ et al, Clin J Sports Med 2010;20:21-27.

This is a really intriguing study that raises a lot of interesting questions and seems to indicate a possible pathway forward for treatment of athletes who suffer from chronic symptoms after a concussion (defined as symptoms at rest more than six weeks, but less than 52 weeks from injury).  Although the majority of athletes with a concussive injury resolve their symptoms within 7-10 days of the injury, a small percentage of these patients go on to develop post-concussion syndrome, with chronic symptoms such as headache, fatigue, insomnia or dizziness that can last for months or longer.  There is some evidence that symptoms of concussion are related to an inability of the brain to properly regulate blood flow according to need.  This is thought to be related in part to impaired nervous system function.  Because exercise often reproduces or worsens post-concussive symptoms, treatment for these patients is typically rest from all activity.  The purpose of this study was to determine if an exercise protocol for post-concussion syndrome patients could be safely reproduced in the office, and secondarily, to see if there was any trend identified to show that exercise was effective toward reducing symptoms in these patients.

Twelve subjects (7 men, 5 women) with post-concussion syndrome (age range:  16-53), an average of 19 weeks post-injury, met criteria for participation in this study.  Symptoms at rest were assessed using a standardized evaluation tool called the Graded Symptom Checklist (GSC).  All subjects were evaluated with a treadmill exercise protocol which involved progressive exercise until the patient’s symptoms began to worsen.  This test was repeated two to three weeks after the initial test was performed.  After this, subjects were instructed to begin daily exercise, 5-6 days per week.  Time of exercise equaled the duration that they were able to exercise on the second treadmill test before symptoms worsened, at an intensity level of 80% of their maximum treadmill heart rate, using a heart rate monitor.  Patients were required to have someone present with them when they exercised and were instructed to cease exercise at the first sign of symptom worsening or when the prescribed duration was reached.  Each subject was observed for sixty minutes after they stopped exercising.  The exercise test protocol was then repeated every three weeks until symptoms were no longer able to be made worse on the treadmill.

During the study, there were no adverse reactions reported.  Prior to study completion, all twelve subjects were eventually able to demonstrate the ability to exercise to exhaustion without worsening of symptoms, with average exercise time increasing from 9.75 to 18.67 minutes – a statistically significant improvement.  No tests had to be terminated because of an adverse reaction.  Eleven of the twelve subjects filled out their Graded Symptom Checklists prior to exercise.  Of these, the average scores decreased significantly over the treatment period.   At follow-up, 10/12 subjects were symptom-free at rest and were able to resume full work, school and athletic activity.

This was not a randomized controlled study, which is the major criticism of it.  However, this was simply a pilot study designed to establish that the protocol itself was safe.  The intriguing thing about this study is the degree to which chronically-symptomatic patients – particularly athletes – improved during the test protocol.  It is possible that these athletes would have improved with time anyway, but none did during the 2-3 week observation period at the start of the study, and the range of time that the group was symptomatic before the study started varied between 6-40 weeks.  The fact that the great majority of these chronically symptomatic patients were able to eliminate their symptoms certainly suggests that the protocol was effective.  Hopefully, this will be more clearly established with a larger follow-up study where patients with post-concussion syndrome are randomized into groups that either complete the above protocol or continue rest, with differences between the two groups observed.

At Stadia, we have begun using this protocol with athletes who meet the proper criteria.  If you are suffering from chronic post-concussion symptoms, give us a call to see if you qualify for treatment.

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