Functional magnetic resonance imaging study of working memory several years after pediatric concussion

ABSTRACT

Primary objective: The neurophysiological effects of pediatric concussion several years after injury remain inadequately characterized. The objective of this study was to determine if a history of concussion was associated with BOLD response differences during an n-back working memory task in youth. Research Design: Observational, cross-sectional. Methods and Procedures: Participants include 52 children and adolescents (M = 15.1 years, 95%CI = 14.4–15.8, range = 9–19) with past concussion (n = 33) or orthopedic injury (OI; n = 19). Mean time since injury was 2.5 years (95%CI = 2.0–3.0). Measures included postconcussion symptom ratings, neuropsychological testing, and blood-oxygen-dependent-level (BOLD) functional magnetic resonance imaging (fMRI) during an n-back working memory task. Main Outcomes and Results: Groups did not differ on accuracy or speed during the three n-back conditions. They also did not differ in BOLD signal change for the 1- vs. 0-back or 2- vs. 0-back contrasts (controlling for task performance). Conclusions: This study does not support group differences in BOLD response during an n-back working memory task in youth who are on average 2.5 years post-concussion. The findings are encouraging from the perspective of understanding recovery after pediatric concussion.

KEYWORDS:

• Brain injury
• children
• adolescent
• chronic
• mild traumatic brain injury

Acknowledgments

Thanks to Lonna Mitchell BA and Kalina Slepicka BA for scoring questionnaires and (alphabetically) Amy Bobyn, Dominique Bonneville BA (Hons), Shauna Bulman, Christianne Laliberté-Durish MSc, Shelby MacPhail, Maya Sohn, and Cole Sugden for assistance with data entry/checking. Thanks to Brenda Turley BA (Hons), Carolyn Emery PhD PT, and Kathryn Schneider PhD PT for assisting with recruitment. Recruitment of some orthopedic control participants was done using the Healthy Infants and Children Clinical Research Program database (HICCUP; http://www.ucalgary.ca/paediatrics_hiccup). Thanks to Elodie Boudes PhD for assistance with the imaging and for helping with some preliminary analyses of the fMRI data. Thank you to the families who participated in this study and generously donated their time to research.

Disclosure statement

Brian Brooks receives royalties for the sales of the Pediatric Forensic Neuropsychology textbook (2012, Oxford University Press) and three pediatric neuropsychological tests [Child and Adolescent Memory Profile (ChAMP, Sherman and Brooks, 2015, PAR Inc.), Memory Validity Profile (MVP, Sherman and Brooks, 2015, PAR Inc.), and Multidimensional Everyday Memory Ratings for Youth (MEMRY, Sherman and Brooks, 2017, PAR Inc.)]. He has previously received in-kind support (free test credits) from the publisher of the computerized cognitive test (CNS Vital Signs, Chapel Hill, North Carolina) used in this study. Keith Yeates receives royalties for book sales from Guilford Press and Cambridge University Press and occasionally serves as a paid expert in forensic cases. Dr. Marc Lebel is an employee of General Electric Healthcare, which is the manufacturer of the 3T MRI used in this study. The remaining authors have no conflicts of interest relevant to this article to disclose.

Additional information

Funding

This study was funded by the Shaikh Family Research Award (an endowment held by the Alberta Children’s Hospital Foundation and granted to Brian Brooks by the Alberta Children’s Hospital Research Institute), with additional support from the Ronald and Irene Ward Chair in Pediatric Brain Injury (awarded to Keith Yeates). Brian Brooks acknowledges salary funding from the Canadian Institutes for Health Research (CIHR) Embedded Clinician Researcher Salary Award. Vickie Plourde acknowledges fellowship funding from the Alberta Children’s Hospital Research Institute (University of Calgary), the Integrated Concussion Research Program (University of Calgary), and Alberta Innovates-Health Solutions. Trevor Low acknowledges summer studentship funding from the Alberta Children’s Hospital Research Institute (University of Calgary), the Integrated Concussion Research Program (University of Calgary), and Alberta Innovates-Health Solutions. Keith Yeates acknowledges funding from the Ronald and Irene Ward Chair in Pediatric Brain Injury.