Attenuation of Spontaneous Baroreceptor Sensitivity after Concussion

Area of Science:

• Neuroscience
• Cardiovascular Physiology
• Sports Medicine

Background:

• Concussion is known to impair cardiovascular autonomic nervous system (CV-ANS) function.
• The arterial baroreflex is crucial for buffering blood pressure changes via CV-ANS modulation.
• Baroreceptor sensitivity (BRS) quantifies the CV-ANS's ability to adapt to metabolic demands, but its post-concussion state is undefined.

Purpose of the Study:

• To investigate the impact of concussion on baroreceptor sensitivity (BRS).
• To assess changes in BRS in athletes within the first week following concussion.

Main Methods:

• Cardiovascular autonomic nervous system assessment, including electrocardiogram and beat-to-beat systolic blood pressure, was conducted on concussed and non-injured athletes.
• Measurements were taken within 48 hours (V1) and 1 week (V2) post-concussion.
• Evaluated changes in heart rate, blood pressure, heart rate variability, blood pressure variability, and BRS (BRSn-Up, BRSn-Dn, BRSn-Avg).

Main Results:

• Concussed athletes exhibited significantly reduced BRSn-Up, BRSn-Dn, and BRSn-Avg compared to controls at both V1 and V2.
• These BRS reductions occurred without significant differences in conventional CV-ANS markers (HF-HRV, LF-HRV, LF-SBP), heart rate, or systolic blood pressure between groups.
• Demographics were matched between the concussion and control groups.

Conclusions:

• Reduced BRS is a consequence of CV-ANS dysfunction in the initial week after concussion.
• The findings suggest that impaired BRS post-concussion may stem from central nervous system injury rather than afferent baroreceptor dysfunction, given similar blood pressure levels.
• This highlights a specific deficit in autonomic cardiovascular regulation following concussion.