Randomized Controlled Trial of Treatment to Optimize Heart Rate Variability for Persistent Post-Concussion Symptoms

Evaluates autonomic function and the intervention process's efficacy, specifically resonance frequency breathing. The HRV Coherence Ratio will be quantified using a non-invasive procedure during resonance frequency breathing conditions and a standardized definition.

This inventory assesses the overall symptom burden, including post-concussion symptoms, on a 5-point scale. It is a well-established measure used by the Department of Defense (DoD) and VA and in mTBI outcome research at large, and includes 27 items that capture vestibular, somatosensory, cognitive, and affective symptoms.

It includes seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction. Higher PSQI scores indicate poorer sleep quality.

Measured using wrist actigraphy, which provides objective data on sleep parameters such as sleep latency, duration, efficiency, fragmentation, and wake time after sleep onset (WASO). Participants will wear the actigraphy monitors at baseline, post-training, and follow-up assessments.

It evaluates patients' perceptions of clinically meaningful changes in their condition following the intervention. It is considered the gold standard for such assessments.

Assessed using the NIH Toolbox Cognitive Battery, which measures executive function, episodic memory, working memory, processing speed, language, attention, and reading through a brief, computer-based test

Evaluated using the TBI-QoL Pain Interference Short-Form, a 10-item questionnaire that measures the extent to which pain interferes with daily activities and overall quality of life. Each BPI-I item is scored from 0="Does not interfere" to 10="Completely interferes," and the scale score is the mean of the 7 items. Scores range from 0 to 10 with higher scores indicating greater pain interference.

Assesses the severity of depressive symptoms over the past two weeks. Scores less than 5 almost always signified the absence of a depressive disorder; scores of 5 to 9 predominantly represented patients with either no depression or subthreshold (i.e., other) depression; scores of 10 to 14 represented a spectrum of patients; and scores of 15 or greater usually indicated major depression.

The PCL-5 (PTSD Checklist for DSM-5) is a screening tool that assesses the presence and severity of PTSD symptoms according to DSM-5 criteria. It's not a diagnostic tool itself but helps clinicians determine if further evaluation is needed. Scores range from 0 to 80, with higher scores indicating more severe symptoms.

participants will receive weekly biofeedback training over a six-week period. Each session includes approximately 30-40 minutes of biofeedback training where participants are affixed with HRV monitoring equipment. They will be guided to synchronize their heart rate variability (HRV) through slow diaphragmatic breathing and focusing on positive emotions. This process involves viewing real-time HRV patterns on a computer monitor, with coaching to help participants achieve resonant frequency breathing.

Six weekly meetings 30-40 minutes, viewing standardized educational content on concussion recovery. No information on breathing will be provided to participants in the Edu group.