title: Longitudinal assessment of local and global functional connectivity following sports-related concussion.
abstract: Growing evidence suggests that sports-related concussions (SRC) may lead to acute changes in intrinsic functional connectivity, although most studies to date have been cross-sectional in nature with relatively modest sample sizes. We longitudinally assessed changes in local and global resting state functional connectivity using metrics that do not require a priori seed or network selection (regional homogeneity; ReHo and global brain connectivity; GBC, respectively). A large sample of collegiate athletes (N = 43) was assessed approximately one day (1.74 days post-injury, N = 34), one week (8.44 days, N = 34), and one month post-concussion (32.47 days, N = 30). Healthy contact sport-athletes served as controls (N = 51). Concussed athletes showed improvement in mood symptoms at each time point (p's < 0.05), but had significantly higher mood scores than healthy athletes at every time point (p's < 0.05). In contrast, self-reported symptoms and cognitive deficits improved over time following concussion (p's < 0.001), returning to healthy levels by one week post-concussion. ReHo in sensorimotor, visual, and temporal cortices increased over time post-concussion, and was greatest at one month post-injury. Conversely, ReHo in the frontal cortex decreased over time following SRC, with the greatest decrease evident at one month post-concussion. Differences in ReHo relative to healthy athletes were primarily observed at one month post-concussion rather than the more acute time points. Contrary to our hypothesis, no significant cross-sectional or longitudinal differences in GBC were observed. These results are suggestive of a delayed onset of local connectivity changes following SRC.
authors.affiliation: Department of Neurosurgery, Neuroscience Research Center, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI, 53226, USA. tmeier@mcw.edu.|The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, NM, 87106, USA. tmeier@mcw.edu.|Laureate Institute for Brain Research, Tulsa, OK, 74136, USA. tmeier@mcw.edu.
authors.forename: Timothy B
authors.initials: TB
authors.lastname: Meier
authors.affiliation: National Institute of Neurological Disorders and Stroke, National Institutes of Health, North Bethesda, MD, 20892, USA.
authors.forename: Patrick S F
authors.initials: PSF
authors.lastname: Bellgowan
authors.affiliation: The Mind Research Network, Lovelace Biomedical and Environmental Research Institute, Albuquerque, NM, 87106, USA.|Departments of Neurology and Psychiatry, University of New Mexico School of Medicine, Albuquerque, NM, 87131, USA.|Department of Psychology, University of New Mexico, Albuquerque, NM, 87131, USA.
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Mayer
mesh_terms: D056352:Athletes; D001265:Athletic Injuries / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001921:Brain / Q000000981:diagnostic imaging / Q000503:physiopathology*; D001924:Brain Concussion / Q000000981:diagnostic imaging / Q000209:etiology* / Q000503:physiopathology*; D003430:Cross-Sectional Studies; D005260:Female; D059907:Functional Neuroimaging; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D012146:Rest; D013334:Students; D014495:Universities; D055815:Young Adult
keywords: Mild traumatic brain injury; Regional homogeneity; Resting state; fMRI