: The results of this systematic review identify the consistent and prevalent indicators of concussion and their associations , derived from the strongest evidence in the published literature .
BACKGROUND : Currently , there is no evidence -based definition for concussion that is being uniformly applied in clinical and research setting s. OBJECTIVE : To conduct a systematic review of the highest- quality literature about concussion and to assemble evidence about the prevalence and associations of key indicators of concussion .
The goal was to establish an evidence -based foundation from which to derive , in future work , a definition , diagnostic criteria , and prognostic indicators for concussion .
Immediate Neurocognitive Effects of Concussion
OBJECTIVE To prospect ively measure the immediate neurocognitive effects and early course of recovery from concussion and to examine the effects of loss of consciousness ( LOC ) and posttraumatic amnesia ( PTA ) on the severity of neurocognitive impairment immediately after concussion . METHODS A sports-related concussion research model was used to allow prospect i ve immediate evaluation of concussion . A total of 2385 high school and college football players were studied . Ninety-one players ( 3.8 % ) sustained concussions during the study . A brief neurocognitive and neurological screening measure , the St and ardized Assessment of Concussion  , was used to assess cognitive functioning before the football season , immediately after injury , and 15 minutes , 48 hours , and 90 days after injury . RESULTS St and ardized Assessment of Concussion scores immediately after concussion were significantly lower than the preseason baseline score and the noninjured population baseline mean , even for injured subjects without LOC or PTA . Subjects with LOC were most severely impaired immediately after injury , whereas those without LOC or PTA were least impaired . Significant impairment was also detected 15 minutes after injury , but all three groups returned to baseline levels of cognitive functioning within 48 hours . CONCLUSION These findings are the first to demonstrate not only that a gradient of increasing concussion severity is represented by PTA and LOC but also that measurable neurocognitive abnormalities are evident immediately after injury without PTA or LOC
: The results of this systematic review identify the consistent and prevalent indicators of concussion and their associations , derived from the strongest evidence in the published literature .
BACKGROUND : Currently , there is no evidence -based definition for concussion that is being uniformly applied in clinical and research setting s. OBJECTIVE : To conduct a systematic review of the highest- quality literature about concussion and to assemble evidence about the prevalence and associations of key indicators of concussion .
The goal was to establish an evidence -based foundation from which to derive , in future work , a definition , diagnostic criteria , and prognostic indicators for concussion .