Due to differences in modalities , time course , study design and outcomes , it is not possible to define a single ‘ physiological time window ’ for SRC recovery .
Multiple studies suggest physiological dysfunction may outlast current clinical measures of recovery , supporting a buffer zone of gradually increasing activity before full contact risk .
Aim or objective The aim of this study is to consoli date studies of physiological measures following sport-related concussion ( SRC ) to determine if a time course of postinjury altered neurobiology can be outlined .
This biological time course was considered with respect to clinical ly relevant outcomes such as vulnerability to repeat injury and safe timing of return to physical contact risk .
Brain magnetic resonance imaging CO2 stress testing in adolescent postconcussion syndrome.
OBJECT A neuroimaging assessment tool to visualize global and regional impairments in cerebral blood flow ( CBF ) and cerebrovascular responsiveness in individual patients with concussion remains elusive . Here the authors summarize the safety , feasibility , and results of brain CO2 stress testing in adolescents with postconcussion syndrome ( PCS ) and healthy controls . METHODS This study was approved by the Biomedical Research Ethics Board at the University of Manitoba . Fifteen adolescents with PCS and 17 healthy control subjects underwent anatomical MRI , pseudo-continuous arterial spin labeling MRI , and brain stress testing using controlled CO2 challenge and blood oxygen level-dependent ( BOLD ) MRI . Post hoc processing was performed using statistical parametric mapping to determine voxel-by-voxel regional resting CBF and cerebrovascular responsiveness of the brain to the CO2 stimulus ( increase in BOLD signal ) or the inverse ( decrease in BOLD signal ) . Receiver operating characteristic ( ROC ) curves were generated to compare voxel counts categorized by control ( 0 ) or PCS ( 1 ) . RESULTS Studies were well tolerated without any serious adverse events . Anatomical MRI was normal in all study participants . No differences in CO2 stimuli were seen between the 2 participant groups . No group differences in global mean CBF were detected between PCS patients and healthy controls . Patient-specific differences in mean regional CBF and CO2 BOLD responsiveness were observed in all PCS patients . The ROC curve analysis for brain regions manifesting a voxel response greater than and less than the control atlas ( that is , abnormal voxel counts ) produced an area under the curve of 0.87 ( p < 0.0001 ) and 0.80 ( p = 0.0003 ) , respectively , consistent with a clinical ly useful predictive model . CONCLUSIONS Adolescent PCS is associated with patient-specific abnormalities in regional mean CBF and BOLD cerebrovascular responsiveness that occur in the setting of normal global resting CBF . Future prospect i ve studies are warranted to examine the utility of brain MRI CO2 stress testing in the longitudinal assessment of acute sports-related concussion and PCS
Due to differences in modalities , time course , study design and outcomes , it is not possible to define a single ‘ physiological time window ’ for SRC recovery .
Multiple studies suggest physiological dysfunction may outlast current clinical measures of recovery , supporting a buffer zone of gradually increasing activity before full contact risk .
Aim or objective The aim of this study is to consoli date studies of physiological measures following sport-related concussion ( SRC ) to determine if a time course of postinjury altered neurobiology can be outlined .
This biological time course was considered with respect to clinical ly relevant outcomes such as vulnerability to repeat injury and safe timing of return to physical contact risk .