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”.
From Brain Injury Professional, the official publication of the North American Brain Injury Society, Vol. 9, Issue 1. Copyright 2012. Reprinted with permission of NABIS and HDI Publishers. For more information or to subscribe, visit: www.nabis.org.
Brain Injury Professional is the largest professional circulation publication on the subject of brain injury and is the official publication of the North American Brain Injury Society. Brain Injury Professional is published jointly by NABIS and HDI Publishers. Members of NABIS receive a subscription to BIP as a benefit of NABIS membership. Click here to learn more about membership in NABIS.