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Mild problem-solving task improves brain function after a concussion, new study suggests

A simple cognitive task as early as four days after a brain injury activates the region that improves memory function, and may guard against developing depression or anxiety

Concern is growing about the danger of sports-related concussions and their long-term impact on athletes. But physicians and healthcare providers acknowledge that the science is evolving, leaving questions about rehabilitation and treatment options.

Currently, guidelines recommend that traumatic brain injury patients get plenty of rest and avoid physical and cognitive activity until symptoms subside.

But a new pilot study looking at athletes with concussions suggests total inactivity may not be the best way to recover after all, say scientists at Southern Methodist University, Dallas, where the research was conducted.

The study found that a simple cognitive task as early as four days after a brain injury activated the region that improves memory function and can guard against two hallmarks of concussion — depression and anxiety.

“Right now, if you have a concussion the directive is to have complete physical and cognitive rest, no activities, no social interaction, to let your brain rest and recover from the energy crisis as a result of the injury,” said SMU physiologist Sushmita Purkayastha, who led the research, which was funded by the Texas Institute for Brain Injury and Repair at UT Southwestern Medical Center, Dallas.

“But what we saw, the student athletes came in on approximately the third day of their concussion and the test was not stressful for them. None of the patients complained about any symptom aggravation as a result of the task. Their parasympathetic nervous system — which regulates automatic responses such as heart rate when the body is at rest — was activated, which is a good sign,” said Purkayastha, an assistant professor in the Department of Applied Physiology and Wellness.

The parasympathetic nervous system is associated with better memory function and implicated in better cardiovascular function. It also helps to regulates stress, depression and anxiety — and those are very common symptoms after a concussion.

“People in the absolute rest phase after concussion often experience depression,” Purkayastha added. “In the case of concussion, cutting people off from their social circle when we say ‘no screen time’ — particularly the young generation with their cell phones and iPads — they will just get more depressed and anxious. So maybe we need to rethink current rehabilitation strategy.”

The new study addresses the lack of research upon which to develop science- and data-based treatment for concussion. The findings emerged when the research team measured variations in heart rate variability among athletes with concussions while responding to simple problem-solving and decision-making tasks.

While we normally think of our heart rate as a steady phenomenon, in actuality the interval varies and is somewhat irregular — and that is desirable and healthy. High heart rate variability is an indicator of sound cardiovascular health. Higher levels of variability indicate that physiological processes are better controlled and functioning as they should, such as during stressful (both physical and challenging mental tasks) or emotional situations.

Concussed athletes normally have lowered heart rate variability.

For the new study, Purkayastha and her team administered a fairly simple cognitive task to athletes with concussions. During the task, the athletes recorded a significant increase in heart rate variability.

The study is the first of its kind to examine heart rate variability in college athletes with concussions during a cognitive task.

The findings suggest that a small measure of brain work could be beneficial, said co-investigator and neuro-rehabilitation specialist Kathleen R. Bell, a physician at UT Southwestern.

“This type of research will change fundamentally the way that patients with sports and other concussions are treated,” said Bell, who works with brain injury patients and is Chair of Physical Medicine and Rehabilitation at UT Southwestern. “Understanding the basic physiology of brain injury and repair is the key to enhancing recovery for our young people after concussion.”

The researchers reported their findings in the peer-reviewed Journal of Head Trauma Rehabilitation, in the article “Reduced resting and increased elevation of heart rate variability with cognitive task performance in concussed athletes.”

Co-authors from SMU Simmons School include Mu Huang and Justin Frantz; Peter F. Davis and Scott L. Davis, from SMU’s Department of Applied Physiology and Wellness; Gilbert Moralez, Texas Health Presbyterian Hospital, Dallas; and Tonia Sabo, UT Southwestern.

Concussion symptom improved with simple brain activity
Volunteer subjects for the study were 46 NCAA Division I and recreational athletes who participate in contact-collision sports. Of those, 23 had a physician-diagnosed sports-related concussion in accordance with NCAA diagnostic criteria. Each of them underwent the research testing within approximately three to four days after their injury.

Not surprisingly, compared to the athletes in the control group who didn’t have concussions, the athletes with concussions entered answers that were largely incorrect.

More importantly, though, the researchers observed a positive physiological response to the task in the form of increased heart rate variability, said Purkayastha.

“It’s true that the concussed group gave wrong answers for the most part. More important, however, is the fact that during the task their heart rate variability improved,” she said. “That was most likely due to the enhancement of their brain activity, which led to better regulation. It seems that engaging in a cognitive task is crucial for recovery.”

Heart rate variability is a normal physiological process of the heart. It makes possible a testing method as noninvasive as taking a patient’s blood pressure, pulse or temperature. In the clinical field, measuring heart rate variability is an increasingly common screening tool to see if involuntary responses in the body are functioning and being regulated properly by the autonomic nervous system.

The parasympathetic is blunted or dampened by concussion
Abnormal fluctuations in heart rate variability are associated with certain conditions before symptoms are otherwise noticeable.

Monitoring heart rate variability measures the normal synchronized contractions of the heart’s atriums and ventricles in response to natural electrical impulses that rhythmically move across the muscles of the heart.

After a concussion, an abnormal and unhealthy decline in heart rate variability is observed in the parasympathetic nervous system, a branch of the autonomic nervous system. The parasympathetic is in effect blunted or dampened after a concussion, said Purkayastha.

As expected, in the current study, heart rate variability was lower among the athletes with concussions than those without.

New findings add evidence suggesting experts rethink rehab
But that changed during the simple cognitive task. For the athletes with concussions, their heart rate variability increased, indicating the parasympathetic nervous system was activated by the task.

Heart rate variability between the concussed and the controls was comparable during the cognitive task, the researchers said in their study.

“This suggests that maybe we need to rethink rehabilitation after someone has a concussion,” Purkayastha said. — Margaret Allen, SMU

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Researchers test blood flow in athletes’ brains to find markers that diagnose concussions

Diagnosing concussions is difficult because it typically rests on subjective symptoms such as forgetfulness, wobbly gait and disorientation or loss of consciousness. A new study of college athletes investigates objective indicators using Doppler ultrasound to measure brain blood flow and blood vessel function.

A hard hit to the head typically prompts physicians to look for signs of a concussion based on symptoms such as forgetfulness, wobbly gait and disorientation.

But symptoms such as those are subjective. And youth who are anxious to get back to their sport can sometimes hide the signs in order to brush off adult concerns, says physiologist Sushmita Purkayastha, Southern Methodist University, Dallas.

Now a new study funded by the Texas Institute for Brain Injury and Repair at U.T. Southwestern Medical Center, Dallas aims to find noninvasive objective indicators to diagnose whether an athlete has suffered a concussion. Using transcranial Doppler ultrasound, the study will probe the brains of college athletes to measure blood vessel function in the brain, looking for tell-tale signs related to blood flow that help diagnose concussion, said Purkayastha, a researcher on the new study.

“We know this is an understudied area. With other health problems, when the doctor suspects diabetes or hypertension, they don’t guess, they run objective tests to confirm the diagnosis. But that’s not the case with concussion — yet,” said Purkayastha, whose research expertise is blood flow regulation in the human brain. “That’s why my research focus is to find markers that are objective and not subjective. And this method of monitoring blood flow in the brain with ultrasound is noninvasive, inexpensive and there’s no radiation.”

Purkayastha and others on the research team are working under a one-year, $150,000 pilot research grant from the Texas Institute for Brain Injury and Repair, a UT Southwestern initiative funded by the Texas Legislature to enhance the diagnosis and treatment of brain injuries.

The team will observe 200 male and female college athletes over the next two years. Half the athletes will be students playing a contact-collision sport who have recently suffered a sports-related concussion. The other half, a control group, will be students playing a contact-collision sport who don’t have a concussion. The study draws on athletes from football, soccer, equestrian sports, cheerleading and recreational sports.

The researchers began testing subjects in August. They expect to have results by the Fall of 2017.

“We are very excited at establishing this collaboration between SMU and the Physical Medicine and Rehabilitation Department at UTSW. Our work with Dr. Purkayastha promises to give meaningful insight into the role of cerebral blood flow mechanisms after concussion and will point us in the right direction for improved neurorecovery,” said physician Kathleen Bell, a leading investigator at U.T. Southwestern’s Texas Institute for Brain Injury and Repair and principal investigator on the study. Bell is a nationally recognized leader in rehabilitation medicine and a specialist in neurorehabilitation.

Diagnosing concussions by using objective, non-invasive and inexpensive markers will result in accurate diagnosis and better return-to-play decisions following a concussion, thereby preventing the long-term risk of second-impact syndrome, said Purkayastha, an assistant professor in the Department of Applied Physiology and Wellness of SMU’s Annette Caldwell Simmons School of Education and Human Development.

“Although sports-related concussions are common, the physiology of the injury is poorly understood, and hence there are limited treatments currently available,” she said.

Hemorrhage or blackouts result, for example, if autoregulation malfunctions
While the brain is the most important organ in the body, it has been very understudied, said Purkayastha, a professor in the Simmons School of Education & Human Development. But since blood vessels in the brain behave similarly to those in the rest of the body, it’s possible to measure blood vessel function in the brain by monitoring blood pressure and brain blood flow. Observing those functions could reveal a marker, she said.

In Purkayastha’s lab on the SMU campus, student athletes are being outfitted with two small ultrasound probes, one on each side of their forehead in the temple area, to test blood vessel function. Specifically, the two probes monitor the blood flow through middle cerebral artery, which supplies blood to 75 percent of the brain. The artery traverses the brain, circulating blood to the brain tissues responsible for movement, cognition and decision-making.

Branching from the middle cerebral artery is a network of blood vessels that get smaller and smaller as they get further from the artery, spreading like tree branches through the brain. The smallest vessels — via a different local regulatory mechanism — maintain constant blood flow to the brain, making microadjustments, such as constricting and dilating in the face of constant changes in blood pressure. Adjustments occur as a person’s muscles move, whether standing, sitting, exercising, or even just laughing and experiencing emotion. These continual adjustments in the vessels — called cerebral autoregulation — keep blood flow constant and regular. That prevents problems such as hemorrhaging or passing out from large fluctuations in blood pressure that is either too high or too low.

Researchers suspect concussion diminishes a vessels ability to properly regulate blood flow
In the current study, ultrasound probes on the temples record the vessels’ microadjustments as digital data. That information is processed through a WinDaq data acquisition software and analyzed to examine cerebral autoregulation with spontaneous changes in blood pressure during that period of time.

Unlike at the doctor’s office, when a cuff is used to measure blood pressure at a rate of single measurements during 30 seconds, Purkayastha’s ultrasound monitoring of blood pressure provides continuous blood pressure recording throughout each heartbeat. As sound waves bounce into the artery and send back an echo, they measure the speed of red blood cells and other blood components moving through the artery.

“We collect 10 minutes of very high frequency data points collecting information on beat-to-beat changes in blood pressure and blood flow to the brain for every single heartbeat,” said Purkayastha. “Then we analyze and post-process and examine how well the blood vessels were able to maintain constant blood flow to the brain. We suspect in people with concussion that the autoregulation function isn’t operating properly which leads to impairments in function such as wobbly gait, disorientation or forgetfulness. This is a noninvasive way to see if there’s a flaw in the autoregulation.”

Athletes with confirmed diagnosis of concussions will be tested three times during the course of the study. The first test is three days after a suspected concussion, the second is 21 days afterward, and the third is three months afterward.

“The pilot studies so far look promising and our goal is to better understand the mechanism behind injury and design objective markers detecting concussion,” said Purkayastha.

The Texas Institute for Brain Injury and Repair at U.T. Southwestern Medical Center, a component of the Harold and Annette Simmons Comprehensive Center for Research and Treatment in Brain and Neurological Disorders, is a collaborative initiative involving local and national organizations, including the National Institutes of Health, University of Texas Dallas and its Center for BrainHealth, Children’s Medical Center, Dallas VA Medical Center, and Parkland Health and Hospital System, as well as Texas Health Resources and Texas Health Ben Hogan Sports Medicine. — Margaret Allen, SMU