History of Brain Injury Alters Cerebral Haemodynamic Oscillations with Cardiac Influence

Area of Science:

• Neuroscience
• Sports Medicine
• Physiology

Background:

• Cerebral autoregulation is impaired following acute mild traumatic brain injury (concussion).
• The long-term effects of repeated concussions on cerebral hemodynamics during autoregulation challenges remain unclear.

Purpose of the Study:

• To investigate cerebral hemodynamic responses during dynamic cerebral autoregulation in athletes with a history of three or more concussions compared to controls.

Main Methods:

• Near-infrared spectroscopy (NIRS) measured pre-frontal cortex oxygenation, and finger photoplethysmography recorded blood pressure.
• Participants underwent a repeated squat-stand maneuver to elicit dynamic cerebral autoregulation.
• Wavelet transformation analyzed signals in cardiac (0.6-2 Hz), respiratory (0.145-0.6 Hz), and smooth muscle (0.052-0.145 Hz) intervals.

Main Results:

• Elevated wavelet amplitudes in the cardiac interval (I) for oxy-hemoglobin and hemoglobin difference were observed in the right pre-frontal cortex.
• No significant differences were detected in the left pre-frontal cortex or blood pressure wavelet amplitudes between groups.

Conclusions:

• History of multiple concussions is associated with increased cardiac contributions to pre-frontal cortex oxygenation during dynamic cerebral autoregulation.
• These findings suggest altered cerebrovascular control mechanisms in individuals with a significant concussion history.