Rebuttal to "Age of first exposure to football and later-life cognitive impairment in former NFL players"
Joseph C.Maroon, Neurosurgeon, University of Pittsburgh Medical Centermaroonjc@upmc.edu
Julian Bailes, Pittsburgh, PA; Michael Collins, Pittsburgh, PA; Mark Lovell, Pittsburgh, PA; Christina Mathyssek, Pittsburgh, PA
Submitted February 23, 2015
The study by Stamm et al. may contain some methodological limitations. [1] The small sample was not representative of the general youth football player because most youth players do not go on to play professional football. In addition, the way football was played by the study subjects in the 1960's to '80's is not representative of the improved, safer practices of modern-day youth football programs.
Second, the authors need to more clearly outline their assessment of important variables such as normal score ranges of the outcome variables and choice of group age cut-off of 12 years and its relevance to the outcome variables.
Most importantly, the retrospective research design and lack of proper control variables may explain group differences aside from "early head impact". Parenting style (as to age of football participation) and socioeconomic factors could also explain group differences. Furthermore, these factors can interact with the type and likelihood of post head-impact care, such as health care access or parents who encourage kids to "toughen up" versus "rest", amplifying alternative explanations of group differences. Other limitations include the use of a sub-optimal neuropsychological battery (WRAT) and no proper determination of actual football incurred head impacts exclusive of other sports played.
Stamm et al. acknowledged some limitations but still concluded that "incurring repeated head impacts during a critical neurodevelopmental period may increase the risk of later-life cognitive impairment." [1] We believe that their message is not warranted based on their research and overstates the scope of the research performed.
For disclosures, please contact the editorial office at journal@neurology.org.
The study by Stamm et al. may contain some methodological limitations. [1] The small sample was not representative of the general youth football player because most youth players do not go on to play professional football. In addition, the way football was played by the study subjects in the 1960's to '80's is not representative of the improved, safer practices of modern-day youth football programs.
Second, the authors need to more clearly outline their assessment of important variables such as normal score ranges of the outcome variables and choice of group age cut-off of 12 years and its relevance to the outcome variables.
Most importantly, the retrospective research design and lack of proper control variables may explain group differences aside from "early head impact". Parenting style (as to age of football participation) and socioeconomic factors could also explain group differences. Furthermore, these factors can interact with the type and likelihood of post head-impact care, such as health care access or parents who encourage kids to "toughen up" versus "rest", amplifying alternative explanations of group differences. Other limitations include the use of a sub-optimal neuropsychological battery (WRAT) and no proper determination of actual football incurred head impacts exclusive of other sports played.
Stamm et al. acknowledged some limitations but still concluded that "incurring repeated head impacts during a critical neurodevelopmental period may increase the risk of later-life cognitive impairment." [1] We believe that their message is not warranted based on their research and overstates the scope of the research performed.
For disclosures, please contact the editorial office at journal@neurology.org.