Abstract Details

Title Comprehensive Literature Review on the Use of Heart Rate Variability as a Biomarker for Concussion Recovery

Topic Neuro Trauma and Critical Care

Presentation(s) P5 - Poster Session 5 (8:00 AM-9:00 AM)

Poster/Presentation
Number 4-007

Objective In this comprehensive review, we will determine whether heart rate variability (HRV) can serve as a biomarker of incomplete concussion recovery.

Background HRV is an index of parasympathetic activity, quantifying the variance between successive heart beats. HRV is often abnormal after severe traumatic brain injury (TBI), but has not been widely studied after concussion until recently. Studies have begun testing the hypothesis that HRV can serve as a biomarker of recovery because the regions vulnerable to concussional forces (e.g., limbic cortex, hypothalamus, and midbrain nuclei) are also key structures in the central autonomic network.

Design/Methods To derive a consensus from this work, we performed a comprehensive literature review of studies that compared HRV in concussed and control populations in varying conditions (e.g., rest, exertion, recovery). From 22 studies (19 adults, 2 adolescents, 1 mixed ages), we extracted HRV metrics in time and frequency domains. We then quantified the proportion of studies showing increased, decreased, or no difference in HRV across concussed and control subjects.

Results

The majority of studies measured HRV during rest, which revealed the most consistent finding of decreased HRV (e.g. HF, RMSSD, and SDNN) in concussed compared to control subjects (12/19 studies). This finding was independent of injury mechanism, chronicity, sex, and age. Moreover, most concussed subjects were asymptomatic. Other findings, such as differences in HRV metrics after sympathetic provocations (i.e., standing, aerobic exercise, hand grip) and parasympathetic provocations (i.e., eye pressure and face cooling) were less consistent or poorly represented. More recently, studies are focusing on adolescents (3/23 studies), sex differences (2/23 studies), and longitudinal protocols (4/23 studies).

Conclusions Our review suggests that HRV may be a proxy for incomplete physiological recovery beyond symptoms. This positions HRV as an adjunct to concussion care, which has become more feasible in the advent of new consumer wearables.

Authors/Disclosures
Rida F. Ismail, BS PRESENTER	Miss Ismail has nothing to disclose.
Kevin Bickart, MD, PhD (UCLA)	Dr. Bickart has nothing to disclose.

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