Heart rate variability (HRV) biofeedback (BFB) can be used to reduce activation of the sympathetic nervous system (SNS) and increase activation of the parasympathetic nervous system (PNS). A growing body of research suggests that increased arousal of the SNS contributes to the sustained state of postconcussion syndrome (PCS). It has also been postulated that underactivation of the PNS may also play a role in the postinjury state of autonomic dystonia, wherein the autonomic nervous system is in a state of imbalance and does not return to normal. In addition to autonomic imbalance, patients who are generally advised not to engage in physical exertion until asymptomatic from concussion, are known to experience secondary symptoms of fatigue and reactive depression. Recent research has established that such symptoms can delay the recovery from concussion indefinitely. By addressing both autonomic dysfunction and the secondary symptoms of depression and anxiety, HRV BFB may be an effective treatment for PCS by strengthening self-regulatory control mechanisms in the body and improving autonomic balance. Recent studies have suggested that HRV BFB has a positive impact in reducing stress and anxiety among athletes, and concussed athletes with higher perceived control over their symptoms have been shown to have faster recoveries post-injury. The primary purpose of the following case study was, therefore, to assess the feasibility of implementing HRV BFB with a concussed athlete suffering from postconcussion syndrome (PCS). The second objective was to prospectively examine the impact of ten weeks of HRV biofeedback on refractory postconcussion symptoms. During this pilot case study, the athlete attended 10 weekly sessions of HRV BFB, according to the protocol set forth by Lehrer, Vaschillo, and Vaschillo (2000). After 10 weeks of HRV biofeedback, the athlete exhibited clinically significant improvements in total mood disturbance, postconcussion symptoms, and headache severity. The results suggest that HRV BFB may be a useful adjunctive treatment for PCS, associated with increases in HRV and enhanced cardiovagal activity. Given these findings, a randomized controlled trial is warranted.
