489 - Neurovascular Coupling in Acutely Concussed Pediatric Patients

Poster Number: 489
Publication Number: 489.100

Patricia R. Roby, Children's Hospital of Philadelphia, Philadelphia, PA, United States; Anne E. Mozel, CHOP, 2716 South St., PA, United States; Christina L. Master, Children's Hospital of Philadelphia, Haverford, PA, United States; Kristy B. Arbogast, Children's Hospital of Philadelphia, Philadelphia, PA, United States

Background: Neurovascular coupling (NVC) uniquely describes cerebrovascular response to neural activation and has demonstrated impairments following concussion in adult patients. It is currently unclear if pediatric patients undergoing dynamic physiological development experience impaired neurovascular coupling acutely following concussion.

Objective: To investigate NVC in acutely concussed pediatric patients relative to controls.

Design/Methods: This prospective cohort study recruited patients presenting to a sports medicine clinic within 28 days of a concussion (cases) or a musculoskeletal injury (controls). Transcranial doppler ultrasound was used to measure changes in patients’ posterior cerebral artery velocity (PCAv) in response to two progressively challenging visual tasks: 1) reading and 2) visual search. Each task was presented in 5 one-minute trials (20s eyes-closed/40s eyes-open). Baseline PCAv data were derived by averaging PCAv across a 2-minute baseline period that preceded the visual tasks. Filtered task data were converted to time-series curves representing 40 consecutive 1-second averages for each trial. Curves were then averaged across the 5 trials and time-aligned to stimulus onset (eyes-open) to generate a single ensemble-averaged 40-second curve representing NVC response for each participant for each task. Independent t-tests were used to assess group differences (case vs. control) in resting PCAv. Separate linear mixed effects models were used to evaluate group differences (case vs. control) in NVC response profiles for both visual tasks.

Results: Twenty-one cases (female=9 (42.9%); age=14.4±1.9 years) and 10 controls (female=5 (50%); age=13.7±1.5 years) were included in our analysis. Average resting PCAv did not significantly differ between cases (36.1±8.4cm/s) and controls (41.9±5.3cm/s) (t29=1.8; p=0.09).  On average, there was little difference between cases and controls on the reading task (cases 1.1% higher) but cases presented with higher relative NVC response curves during the visual search task (4.4% higher) relative to controls (Figure 1).Conclusion(s): Our data indicate that concussed patients present with elevated NVC response to visual tasks, particularly the more complex visual search task. This may suggest that concussed patients require increase neural resource allocation to complete a visual task relative to controls. The study provides insight into the neurophysiological consequences of concussion in pediatric patients.
Figure 1Figure 1. Relative PCAv ensemble-averaged across 5 trials for cases (blue) and controls (red) in response to A) the reading task and B) the visual search task. On average, cases presented with a higher NVC response to the reading task (1.1% increase) and to the visual search task (4.4% increase).