According to the Centers for Disease Control (CDC), between 1.7 and 3.6 million people suffer a traumatic brain injury (TBI) each year. Of these, 10% are sustained from sports and recreational activities, and the number of ER admissions for TBI increased by 62% in recent years. One study found that 47% of skiing and 40% of snowboarding injuries involve a head injury, with concussions (mild TBIs) being the most common. And endurance athletes aren’t immune to head injury, particularly those involved in high-speed cycling crashes or trail running falls.
With TBIs on the rise, effective treatment is more crucial than ever, and biofeedback training is a promising modality.
What is biofeedback?
In the late 1960s, researchers began to combine elements of psychology, neurology, physiology, and other disciplines to find new ways of measuring brain and nervous system activity and changing them. In 1969, Neal Miller published an article in Science on the “Learning of Visceral and Glandular Responses,” and a team led by Elmer Green released the paper “Self-Regulation of Internal States.” Later that year, the Biofeedback Research Society held its inaugural meeting in Santa Monica, giving the discipline its name. In the decades that followed, biofeedback was incorporated into the multidisciplinary treatment of veterans and civilians who suffered TBIs.
According to an article by Neurofeedback.io, “Biofeedback is a technique whereby a person can learn to control functions of the body which are normally regulated subconsciously, such as blood pressure and flow, head muscle tension, perception of pain, breath, and heart rate. Voluntary control is gained by giving the brain feedback, through visual or auditory stimulus, on whether the desired state is being attained or not.”
The comprehensive application of biofeedback training for TBI recovery typically takes place in a hospital or rehab center setting. This gives a patient access to the expertise of a professionally licensed clinician, who tests their physiology, guides them through one or more of the main types of biofeedback utilizing several clinical-grade sensors, and demonstrates how the interventions impact autonomic nervous system (ANS) regulation.
To help provide an expert perspective on biofeedback training, I reached out to Dr. Jason Nupp, a board-certified rehabilitation psychologist and academy-certified brain injury specialist. He spent his first 10 years at the world-renowned Craig Hospital in Denver on a multidisciplinary inpatient combo team that treated patients who’d suffered a brain or spinal injury or both. For the past five years, he has focused on outpatient neuropsychiatry.
Nupp told me that his role in walking a TBI patient through biofeedback training is similar to that of a coach educating an athlete on how a particular exercise should look and feel. As an experienced endurance athlete who has used TrainingPeaks to train for multiple ultras, it’s no surprise that he provided a running analogy.
“When a patient starts to understand how they can control their autonomic nervous system responses, it’s like when you’re in a running flow and your gait, heart rate, and breathing all sync up,” Nupp said.
The basics of biofeedback training
These are some of the most common elements of biofeedback training that are used in a clinical setting:
- Surface Electromyography (sEMG): Detects the level of muscle tension and activation and helps patients learn to relax muscles to manage stress or anxiety.
- Thermal (Temperature) Biofeedback: Tracks skin temperature, typically at the fingertips, as a window into a person’s stress levels.
- Electroencephalogram (EEG/Neurofeedback): Records the brain’s electrical activity to help regulate neurological and psychological conditions and can be used as a tool for achieving deeper relaxation.
- Galvanic Skin Response (GSR/Electrodermal Activity): Picks up on changes in sweat gland output, which is a highly responsive marker of psychological stress and emotional activation.
- Respiration/Breathing Training: Employs sensors worn around the torso to track breathing patterns, guiding patients toward breathing habits that support a balanced ANS.
- Heart Rate Variability (HRV) Training: Analyzes the subtle fluctuations in timing between heartbeats as a measure of how well the ANS is functioning, with the goal of reducing anxiety and improving overall physiological resilience.
Endurance athletes may be uniquely primed for successful biofeedback training, as they’re often already accustomed to tracking recovery metrics and staying attuned to their body’s nervous system. When recovering from a TBI, athletes can use these familiar metrics to gauge how their body is adapting.
How head injuries impact the nervous system
Nupp stated that a concussion or any other kind of TBI causes a variety of symptoms that impact the body and brain via the branches of the nervous system. These can include impaired cognition and motor function, changes in mood and behavior, sleep dysfunction, and pain—which can be the result of orthopedic injuries sustained along with a brain injury.
“A TBI has a wide-ranging impact on the nervous system,” Nupp said. “In the early stages of treatment, we often focus on getting a patient stable medically and dealing with the impact on the central nervous system. Then we can turn our attention to the autonomic nervous system, which is where biofeedback training comes in.”
The ANS is a component of the peripheral nervous system and modulates involuntary physiological processes, such as blood pressure, heart rate, sexual arousal, respiration, and digestion.
The ANS comprises two divisions:
- The sympathetic nervous system triggers a fight, flight, or freeze response that helps a body prepare for danger. TBI patients can get stuck in this state, which disrupts their sleep and digestion and makes them feel constantly threatened, hyperaware, and anxious.
- The parasympathetic nervous system prompts a rest, relax, and digest response that helps you wind down and recover. It’s sometimes blunted by a TBI; other times, it can become overstimulated, leading to chronic fatigue and sleepiness.
“I often explain that the relationship between the parasympathetic and sympathetic responses is like a seesaw,” Nupp said. “In TBI patients, one side or the other is often up in the air. We use biofeedback training as a method to help rebalance that autonomic dysfunction.”
Inside a biofeedback session
To give greater insight into what a TBI patient experiences during biofeedback training, Nupp outlined the basic process of a typical first session.
- Establishing a baseline. The patient completes a comprehensive assessment that incorporates quantitative and qualitative evaluations. Another significant component is the Psychophysiological Stress Profile (PSP), which provides a picture of how the individual’s ANS is responding to pain, stress, or agitation. This measures key indicators, like muscle tension, sweat gland activity, and skin temperature.
- Mental stressor. The clinician introduces a cognitive demand that can lead to a stress response. Nupp often asks a TBI patient to count backward from a big number in sevens. He then shows the patient how their body and brain are responding using several biosensors.
- Recovery phase one. The patient is given several minutes to recover. This gives the clinician an opportunity to see how much they can relax their autonomic system after the mental stressor without external cueing.
- Physical stressor. This phase measures how the patient responds to a physical stimulus. Nupp often starts by asking the patient to immerse their hand in chilly water and hold it there until the cold sensation becomes uncomfortable.
- Recovery phase two. The patient gets a few minutes to bounce back from the cold-water immersion test or other physical stressor. The clinician will give them the chance to relax on their own and then introduce a coping technique to enhance and expedite their recovery.
“Each of these five phases gives me important insights about how the TBI patient’s autonomic nervous system is functioning with and without a stimulus present,” Nupp said. “Then I take that information and develop a personalized treatment plan based on their needs and symptoms. When I’m trying to treat headaches or migraines, I might use hand warming techniques to alter peripheral skin tone. Whereas if they’re struggling with agitation or anxiety, I could use electrodermal modalities.”
Continuing biofeedback training outside the clinic
As important as his one-on-one treatments for TBI patients are, Nupp emphasized his desire to empower them to take charge of their own long-term recovery. “My mentor in biofeedback told me that our end goal should be to make ourselves irrelevant,” he said. “Eventually, a TBI patient shouldn’t need the feedback from the computer to know what’s going on inside their body—they should be able to associate a subjective feeling of relaxation or improved cognition with whatever technique we’re using.”
As such, Nupp tries to act as a bridge between the quantitative data and the qualitative experience that a patient has. Initially, there could be a disconnect between the two, but as the treatment progresses, the data-driven representations they hear or see should start to correlate with how changes in skin temperature, respiratory rate, and other variables make them feel.
Biofeedback training typically lasts for six to 10 sessions but can go as long as 12. Nupp tells his TBI patients that they should start noticing a difference within the first three to four visits—sooner if they do the exercises he gives them as homework.
“The success of biofeedback training largely depends on what people do on their own between sessions,” Nupp said. “If they make it part of their daily life, then they’ll see better results. When they come back in, I’ll notice that they’ve made significant progress and have changed the baseline of their autonomic responses.”
Here are three exercises that Nupp walks patients through and encourages them to practice on their own:
- Diaphragmatic breathing. “One of the simplest ways to impact respiration rate, heart rate, and HRV is to do several minutes of calm nasal breathing from the diaphragm,” Nupp said. He mentioned a study released via the International Journal of Psychophysiology that tested variable breathing patterns and showed that 5.5 breaths per minute with an equal inhale and exhale had the greatest impact on optimizing HRV.
- Mental imagery. One way for patients to relax their muscle tone and balance their ANS is visualizing being in a calming environment, like lying on a beach in perfect weather or spending a sunny day in the mountains. It works much like an athlete mentally rehearsing a race.
- Progressive muscle relaxation. “Tensing and relaxing different muscle groups can help them downregulate,” Nupp said. He usually advises a patient to start at their head or shoulders and calmly work their way down the body. By the time they reach their feet, they’ve usually gone from feeling tense to relaxed.
How biofeedback training helps athletes recover from a TBI
A paper published in the American Journal of Occupational Therapy noted that “Implementation of biofeedback breathing protocols have demonstrated positive outcomes for anxiety, perceived stress, and heart rate variability.” It has also been shown to resolve sleep disturbances, stabilize mood, and reduce hyperarousal.
In addition to ANS regulation improvements, Nupp finds that self-reported, qualitative responses reveal additional positive effects of biofeedback training. “A lot of my patients share improvements in pain-related symptoms and general well-being,” he said. “Cognitively, people report improvements in attention, working memory, and executive functioning. There’s also a sense of self-efficacy, because biofeedback training gives TBI patients a chance to help themselves.”
Athletes can use various monitoring technologies to evaluate their progress. Some of these are clinical-grade devices that measure multiple kinds of biofeedback, such as Thought Technology’s finger-worn eVu TPS. Single-use solutions like Mindfield eSense Pulse and Optimal HRV measure heart rate variability.
Smartwatches from Suunto, Apple, and Garmin, the Whoop Band, and the Oura Ring—which most endurance athletes already use—allow patients to see how biofeedback training enhances their sleep quality and recovery over time. Once their TBI symptoms improve and they’re cleared to resume training, athletes can track recovery data with performance markers in TrainingPeaks.
“Improving aerobic fitness is crucial for TBI patients,” Nupp said. “Focusing on sleep hygiene and dialing in diet and supplementation to tackle inflammation can amplify the benefits of biofeedback training.”
Resources
Nonfatal Traumatic Brain Injuries Related to Sports and Recreation Activities Among Persons Aged ≤19 Years — United States, 2001—2009. Retrieved from https://www.cdc.gov/mmwr/preview/mmwrhtml/mm6039a1.htm#
Stuart, C.A. et al. (2020, March). Skiing and Snowboarding Head Injury: A Retrospective Centre-Based Study and Implications for Helmet Test Standards. Retrieved from https://www.sciencedirect.com/science/article/abs/pii/S0268003319305303#
Moss, Donald (1998). Humanistic and Transpersonal Psychology: A Historical and Biographical Sourcebook. Westport, CT: Greenwood Publishing. Retrieved from https://nealmiller.org/?p=94
The History of Neurofeedback. Retrieved from https://neurofeedback.io/the-history-of-neurofeedback
McCorry, Laurie Kelly. (2007, August). Physiology of the Autonomic Nervous System. Retrieved from https://pmc.ncbi.nlm.nih.gov/articles/PMC1959222
Lin, IM et al. (2014, March.) Breathing at a Rate of 5.5 Breaths Per Minute with Equal Inhalation-to-Exhalation Ratio Increases Heart Rate Variability. Retrieved from https://pubmed.ncbi.nlm.nih.gov/24380741
Hove, Kelsee, et al. (2020, August). Implementation of Biofeedback Interventions for the Treatment of Adults with Post-Concussion Syndrome. Retrieved from https://doi.org/10.5014/ajot.2020.74S1-PO7725
