Physiologic Post Concussion Disorder

Ray was known as Razor to his friends and teammates. After a concussion three months  ago Ray hasn’t seen much of his teammates, or for that matter, much of anyone. He has improved somewhat in the past few weeks. His headache is pretty much constant but low level. He still has light and noise sensitivity but his primary complaint is his inability to concentrate.

When he walked into our Concussion Management Clinic at the University at Buffalo he wore sunglasses and looked fairly depressed. His family doctor had heard about our program and liked the fact that we actively treat post concussion disorders and Ray was clearly not benefitting from the more typical approach of rest and withdrawal from activity.

Ray saw Dr. John Leddy, the director of the clinic, and told him how he was injured returning a punt for his varsity team. It was a helmet to helmet collision that Ray could describe because he had seen it on film. He had no memory of the event otherwise.

After determining that Ray’s symptoms and physical health were such that an exercise stress test would be safe, Dr. Leddy instructed Ray to change into his running shoes and track pants. Ray then nervously stepped on the treadmill. Our Physical Therapist, Scott, has conducted hundreds of these tests and knows just how to help athletes relax. Scott reinforced what Dr. Leddy had already told Ray, that he must not work through any changes in symptoms. Ray was instructed to report everything he experienced. During the treadmill test Scott asks every two minutes about changes in how Ray is feeling.

Ray started out well on the treadmill. In fact, he quite enjoyed doing a little exercise after so many months on the couch. He did not know it but his heart rate and blood pressure were increasing faster than they should for an athlete, even an athlete that has begun to de-condition. When his heart rate reached 160 beats per minute Ray suddenly felt strange and uncomfortable, even though it was not a particularly difficult level of exertion for him. Scott could see the change in Ray’s demeanor and immediately asked how he was feeling. Ray said he was feeling like someone had just tightened a rubber band around his head. Scott stopped the test immediately. Scott also observed that Ray’s heart rate and systolic blood pressure were unusually high for his level of exertion.

With the data from the exercise test in hand Dr. Leddy explained to Ray that indeed he was still suffering physiologic effects of his concussion. “However,” he said, “there is good news, as well. A heart rate of 152 means the recovery process is happening and we can speed that recovery process along.” Dr. Leddy then explained that Ray should exercise 20 minutes a day at a heart rate of 130 beats per minute and that after a few weeks we would increase the level of exercise based on his progress. A big smile came across Ray’s face. He could not believe that he could exercise again, even if it was at this relatively low level.

A few weeks later when it was determined that Ray could exercise to a heart rate of 178 beats per minute without exacerbation of symptoms, his exercise prescription was increased to 20 minutes at 160 beats per minute, two times a day. Ray could see the light at the end of the tunnel and it wasn’t far away.

Symptoms versus signs of concussion

Several weeks after Ray’s visit we heard from Dr. Sara Meagan, Ray’s family doctor. She was curious about the process we used to evaluate Ray’s post concussion disorder. She was especially curious about the use of an exercise stress test to evaluate Ray.

We began by explaining that most clinics diagnose concussion and post concussion disorder on the basis of symptoms. In fact, the DSM IV (Diagnostic and Statistical Manual of the American Psychiatric Association) and the World Health Organization definitions of post concussion disorders rely heavily on symptoms. Only the DSM IV asks also for evidence of a cognitive deficit based on cognitive testing. Symptoms, of course, are what the patient describes. These include headache, fatigue, sleep disturbance, vertigo, irritability, depression, apathy, sensitivity to light and/or noise, difficulty with concentration, etc.

Symptoms describe the subjective experience of the patient and are important to tell the doctor what the patient is feeling. However, for many diseases or disorders, symptoms are not sufficient to establish a diagnosis. Dr. Meagan was well aware that medical signs when detected by a physician provide a far more objective indication of disease or disorder. But she was unaware of the signs associated with concussion. We quickly summarized the relevant research on physiologic characteristics of individuals with post concussion disorders.

First and foremost, an individual’s resting heart rate is increased after traumatic brain injury.(King, Lichtman, Seliger, Ehert, & Steinberg, 1997) Perhaps more importantly, the rate at which the heart rate increases with exercise is accelerated in concussed patients. (B. Gall, W. S. Parkhouse, & D. Goodman, 2004) The heart rate increase seen with cognitive stress is also greater in concussed patients. (Hanna-Pladdy, Berry, Bennett, Phillips, & Gouvier, 2001)

Individuals with post concussion disorders also have autonomic nervous system dysregulation, which is expressed as overactive sympathetic nervous system activity. (B. Gall, W. Parkhouse, & D. Goodman, 2004; King, et al., 1997) Dr. Meagan remarked that this would explain why many patients complain of light sensitivity. She knew that pupils are dilated during sympathetic activity. We explained that it may also be responsible for why so many patients have difficulty falling asleep. In order to fall asleep, the parasympathetic system has to take charge, and an overactive sympathetic system prevents the individual from entering the relaxed state that is required in order to fall asleep.

Finally, we pointed out that patients with post concussion disorder often have difficulty regulating cerebral blood flow. (Junger et al., 1997) Simply put, the brain cannot perform well when the blood pressure in the brain is too high. During exercise or any other time that one experiences a substantial increase in blood pressure, the brain is protected by an auto-regulatory process. After a concussion this auto-regulatory process is disrupted. Dr. Meagan interrupted the educational program: “While I can certainly see the advantages to evaluation of signs versus symptoms of concussion, as a general practitioner I don’t see how I can assess someone for cerebral blood flow or autonomic nervous system balance in my practice”.

We pointed out that the disruption of regulatory processes is only revealed when the system is under stress. We only monitor cerebral blood flow during exercise and only in research. However, when we assess patients, like Ray, their inability to regulate cerebral blood flow becomes evident with the exacerbation of symptoms during exercise. Ray’s description of the “rubber band around my head” was typical of the subjective experience of excess blood flow to the brain.

“OK. Now your exercise test makes sense. But why did regulated exercise help Ray regain control of his regulatory processes?”

Regular exercise helps non-concussed individuals to become fit in part by improving regulatory control of cerebral blood flow and restoring autonomic nervous system balance. By prescribing an exercise program below the threshold at which Ray experienced distress, Ray was able to slowly regain his fit state. As an athlete, Ray’s recovery will be much faster but the same principles apply to non-athletes.

“Are there some who experience post concussion disorders for whom your exercise test and regulated exercise program is not appropriate?”

We do not recommend the test for patients who have ongoing symptoms after concussion unless the symptoms persist 3 weeks or more, after which the test is safe. We also do not recommend the test in patients with other health conditions that preclude exercise or increase the risk for a cardiac event during intense exercise. However, the test is very helpful in the differential diagnosis of the nature of the post concussion disorder. When someone is able to exercise fully without exacerbation of symptoms but still has problems, then we consider other causes. Some patients have ocular-vestibular difficulties or cervicogenic (neck) problems. There is also a group of patients who have anxiety or depressive disorders. So far we are only recommending the regulated exercise program for those with physiologic post concussion disorder (which we define as inability to exercise to exhaustion due to loss of regulatory control of cerebral blood flow during exercise).

Dr. Meagan thanked us for our time and indicated that she would be keen to learn how to assess patients herself. She has access to a treadmill and sees a substantial number of athletes from the local college. We explained that we have been providing training to clinicians at a number of programs and we would be happy to provide that training to her. We also explained that our research articles are available on our website: http://concussion.buffalo.edu.

Ray exercises to exhaustion without symptom exacerbation

It has been seven weeks since Ray first visited the Concussion Management Clinic at the University at Buffalo. He has been feeling better and, more important from his perspective, he has been able to return to school and perform up to his normal high

standards. But he was nervous once more as he approached the treadmill test. Scott reassured him that he is not likely to do any worse than before and since his last test was so good he was sure to do even better.

Ray was able to exercise to exhaustion without that feeling of tightness in his head or any other symptoms. In fact, he felt really good when he completed the treadmill test. He had not experienced the high that comes from a good workout since he had his concussion. He had forgotten how good it feels.

Meeting with Dr. Leddy to discuss the results, Ray could not stop smiling. Dr. Leddy’s assessment that he was fully recovered from his concussion came as no surprise, but it was reassuring to hear it from the doctor. Ray asked “So what happens now?”

Dr. Leddy indicated that since the football season was over there was no need to worry about return to play. He asked Ray how his studies were going and whether he was able to concentrate. Ray told him studying was no longer a problem. He also indicated that his sensitivity to noise and light was also not presenting a problem. Ray then indicated he was thinking of giving up football and wanted Dr. Leddy’s opinion. “Only you can decide how important football is in your life, but it is true that once you have had a concussion, especially one with long lasting physiologic effects, you are more likely to get a subsequent concussion, if that is what you are worrying about.”

“That is precisely what I am worried about. These past months have been difficult and have forced me to evaluate my priorities. I missed school more than I missed football.”

Prologue

Ray is a fictional case based on a composite of a number of similar cases we have seen over the past few years since we started to use this physiologic approach to assessment and treatment of post concussion disorders. The chances for individuals with prolonged physiologic symptoms of concussion to improve and return to their normal level of function have improved dramatically over the past decade. In our research we found that 77% of patients recovered fully like Ray (Baker et al, 2012). In some instances, especially with non-athletes, patients who refuse to exercise have very poor outcomes. Those that do follow the exercise prescription but do not recover fully will have signs and

symptoms of other types of post concussion disorders. Among the most common disorders that did not fully recover with exercise were patients with ocular-vestibular symptoms and some patients, who despite being able to exercise to full capacity without symptom exacerbation, had persistent difficulty with concentration upon return to school or work.

References

Baker, JG; Freitas MS; Leddy, JJ; Kozlowski KF and Willer, BS (2012) “Return to full functioning after graded exercise assessment and progressive exercise treatment of postconcussive syndrome” Rehabilitation Research and Practice, Vol 2012; 705309, 7 pages.

Gall, B., Parkhouse, W., & Goodman, D. (2004). Heart rate variability of recently concussed athletes at rest and exercise. Med Sci Sports Exerc, 36(8), 1269-1274.

Gall, B., Parkhouse, W. S., & Goodman, D. (2004). Exercise following a sport induced concussion. Br J Sports Med, 38(6), 773-777.

Hanna-Pladdy, B., Berry, Z. M., Bennett, T., Phillips, H. L., & Gouvier, W. D. (2001). Stress as a diagnostic challenge for postconcussive symptoms: sequelae of mild traumatic brain injury or physiological stress response. Clin Neuropsychol, 15(3), 289-304.

Junger, E. C., Newell, D. W., Grant, G. A., Avellino, A. M., Ghatan, S., Douville, C. M., . . .

Winn, H. R. (1997). Cerebral autoregulation following minor head injury. J Neurosurg, 86(3), 425-432.

King, M. L., Lichtman, S. W., Seliger, G., Ehert, F. A., & Steinberg, J. S. (1997). Heart-rate variability in chronic traumatic brain injury. Brain Inj, 11(6), 445-453.