A combination of gradual aerobic exercise and breathing practice can help ease persistent postconcussive symptoms, preliminary findings from a new study suggest.
Heart rate variability biofeedback (HRVB) and progressive aerobic exercise (PAE) were each helpful on their own, but combining them led to even greater improvement in cognition, depression, and mood.
"Managing persistent concussion symptoms is particularly challenging as there are no standard therapies," study investigator R. Davis Moore, PhD, from the University of South Carolina in Columbia, said in a news release.
"These therapies are inexpensive, easy to implement, and can be self-administered, making them feasible and accessible for everyone with persistent symptoms," Moore noted.
The study was released early, ahead of presentation in Boston next month at the American Academy of Neurology (AAN) Annual Meeting.
Targeting Autonomic Dysfunction
Concussion can affect the autonomic nervous system, and it is "increasingly clear that this underlies the inability to tolerate exercise, problems with thinking skills, and mood issues in those with persisting symptoms," Moore explained.
Preliminary research suggests that HRVB and PAE can improve cardio-autonomic dysfunction and clinical symptoms.
However, until now, no study has evaluated whether there is additional benefit from combining the two.
The investigators randomly assigned 30 teens with postconcussive symptoms that had lasted more than 1 month to a 6-week intervention consisting of either HRVB, PAE, or HRVB+PAE.
The HRVB group practiced resonant-frequency breathing using a handheld biofeedback device for 20 minutes 4 nights a week. The PAE group completed a 3-day-a-week aerobic exercise protocol that gradually increased in intensity and duration. The HRVB+PAE group did both. Concussion symptoms, HRV, cognition, and mood were assessed at baseline and again 6 weeks later.
All participants experienced improvement in sleep, mood, cognition, and autonomic function, but those who received the combined biofeedback and exercise intervention experienced greater improvements than peers who engaged in exercise or received biofeedback alone.
The study's topline results, which were released ahead of the presentation, show that HRVB+PAE is associated with a twofold greater reduction in symptom severity compared with PAE only and a 1.3 times greater reduction in symptom severity compared to HRVB only.
Similarly, HRVB+PAE led to a 1.2 times greater reduction in symptoms of depression compared with PAE only and a 1.3 times greater reduction HRVB only.
The combined group also experienced more than 1.4 times the reduction in total mood disturbance than was provided by exercise or biofeedback alone.
The combined group also experienced significantly greater improvements in attention and working memory, as well as greater changes in metrics of HRV than the groups that participated in exercise or biofeedback alone.
Moore and colleagues caution that the current results are preliminary and that future studies are needed with larger groups of people.
A limitation of the study was that it did not include a control group of people with persistent postconcussive symptoms who received no intervention.
Commenting on the findings for Medscape Medical News, neuroscientist José Posas, MD, director of the Ochsner Neurology Residency Program, New Orleans, Louisiana, who wasn't involved in the study, said these preliminary results are "promising" but cited the small number of participants as a limitation.
Posas said the results "fit with what’s known about the role of postconcussion autonomic dysfunction in persisting postconcussive symptoms.
"Managing persistent concussion symptoms can be challenging," he added, and this study supports "exercise as medicine" as well as taking a "mind-body, holistic approach" to postconcussion recovery," said Posas.
Also weighing in, Michael F. Bergeron, PhD, clinical and scientific advisor, Department of Performance Health, Women's Tennis Association, noted that "each of these therapeutic interventions has been around for some time now. Neither is new.
"Heart rate variability biofeedback based on variation in heart rate corresponding to breathing has been shown to be effective in treating numerous conditions, including reducing (nonclinical) stress, anxiety, depression, anger, and posttraumatic stress disorder in veterans and in some instances enhancing athletic performance. Of course, the validity and reliability of the commercially available apps and devices are potential significant limitations, as well as the stability of the user's technique," Bergeron told Medscape Medical News.
"It’s also been recognized that low-level aerobic exercise treatment normalizes the cerebrovascular physiological dysfunction in patients with concussion by increasing CO2 sensitivity, which normalizes exercise ventilation and cerebral blood flow and thus reduces some symptoms," Bergeron added.
"The combination of treatments is likely the novel aspect, which makes sense because brain injury is complex, and effective interventions need to utilize a complex, integrated biological systems approach across the multiple interdependent domains of influence," Bergeron said.
The study was supported by the nonprofit Woodcock Institute at Texas Woman’s University. Moore, Bergeron and Posas have disclosed no relevant financial relationships.
American Academy of Neurology (AAN) 2023 Annual Meeting: Abstract 4141. To be presented April 22, 2023.
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