A history of multiple concussions does not alter the transcranial doppler-based assessment of the neurovascular coupling response

Abstract

ObjectiveTo determine how a history of 3+ concussions alters elevations in cerebral blood velocity (CBV) in the posterior cerebral artery (PCA) during visual tasks.DesignRetrospective Cohort.SettingLaboratory.Participants136 male contact-sport athletes (19.1±1.4 years, 66 football, 70 hockey) were recruited; 39 presented with 0 previous concussions, 16 with 3+ previous concussions; exclusion criteria included history of concussion within 6 months.InterventionTranscranial Doppler ultrasound indexed PCA-CBV during a series of visual tasks. Participants closed their eyes (20-seconds) and, when prompted, opened their eyes to complete a visual task (40-seconds). Testing occurred prior to the start of their athletic season. The visual trial raw traces were averaged together to enhance the signal-to-noise ratio of outcome measurements. The independent variable tested was concussion history.OutcomesEyes-closed CBV (cm/s), peak elevation in CBV after eyes-open (cm/s), relative change in CBV (%), and total activation during the first 30 seconds of the task (indexed via area under the curve-AUC)Main resultsIndependent samples T-Tests indicated there were no effects of concussion history on any outcome: Eyes-closed CBV (p=0.950), peak CBV (p=0.903), % CBV elevation (p=0.593), and AUC (p=0.718).ConclusionsA history of multiple concussions does not alter the cerebrovasculature’s ability to maintain nutrient delivery required for visual challenges in cortical areas supplied by the PCA. This is an important finding; despite the long-term neurocognitive deficits associated with a history of concussions, the transcranial Doppler assessment of neurovascular coupling appears intact for this population of younger adult contact-sport athletes.Competing interestsNone.