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

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.

Alteration in Cerebral Activation during a Working Memory Task after Pediatric Mild Traumatic Brain Injury: A Prospective Controlled Cohort Study.

Mild traumatic brain injuries (mTBIs) commonly occur in children and adolescents and can result in persistent cognitive symptoms. The neurophysiological changes that underlie persistent post-concussive symptoms (PPCS) have not been characterized. Our objective was to compare working-memory related functional magnetic resonance imaging (fMRI) response in children with persistent symptoms after mTBI at one month post-injury to children with typical recovery and healthy controls. This was a prospective, controlled cohort study of children with mTBI at one month post-injury. PPCS was defined as children with a 10-point increase in their post-concussion symptom inventory score (compared with pre-injury score) at one month post-injury and a two-point increase in at least two symptom categories compared with pre-injury. One hundred and seven participants (60 PPCS, 30 recovered mTBI, and 17 controls) with a mean age of 14.2 years (standard deviation [SD] 2.5) (44% male) were assessed 38 (SD 5.9) days after mTBI. The primary outcome measures were visuospatial n-back working memory task performance and fMRI blood oxygen level dependent (BOLD) signal change. Children with PPCS had decreased activation relative to children with typical recovery in the posterior cingulate and precuneus during the one-back working memory condition, despite similar task performance. Differences in cortical activation in children with PPCS at one month highlight the persistent neurobiological consequences of pediatric mTBI on working memory cortical activation. These findings encourage recommendations to avoid contact sports and provide continued care at school for children with persistent symptoms at one month post-injury.

Incorporating a Computerized Cognitive Battery Into the Emergency Department Care of Pediatric Mild Traumatic Brain Injuries-Is It Feasible?

OBJECTIVES: The use of computers to test cognitive function acutely after a concussion is becoming increasingly popular, especially after sport-related concussion. Although commonly performed in the community, it is not yet performed routinely in the emergency department (ED), where most injured children present. The challenges of performing computerized cognitive testing (CCT) in a busy ED are considerable. The aim of this study was to evaluate the feasibility of CCT in the pediatric ED after concussion. METHODS: Children, aged 8 to 18 years with mild traumatic brain injury, presenting to the ED were eligible for this prospective study. Exclusion criteria included the use of drugs, alcohol, and/or physical injury, which could affect CCT performance. A 30- or 15-minute CCT battery was performed. Feasibility measures included environmental factors (space, noise, waiting time), testing factors (time, equipment reliability, personnel), and patient factors (age, injury characteristics). RESULTS: Forty-nine children (28 boys; mean age, 12.6; SD, ± 2.5) participated in the study. All children completed CCT. Mean testing times for the 30- and 15-minute battery were 29.7 and 15.2 minutes, respectively. Noise-cancelling headphones were well tolerated. A shorter CCT was more acceptable to families and was associated with fewer noise disturbances. There was sufficient time to perform testing after triage and before physician assessment in over 90% of children. CONCLUSIONS: Computerized cognitive testing is feasible in the ED. We highlight the unique challenges that should be considered before its implementation, including environmental and testing considerations, as well as personnel training.