Martin L. Rohling, Mobile, Alabama; Laurence M. Binder, Beaverton, Oregon
Submitted March 10, 2015
Stamm et al. [1] reported poorer cognitive performance for former professional football players starting play before age 12 (age of first exposure (AFE) less than 12) vs.
those starting greater than or equal to 12. One variable, WRAT-4 Reading, is often used to estimate premorbid cognitive ability due to its resistance to acquired adult cerebral dysfunction in all but aphasic or significantly demented individuals. [2] Using meta-analysis, we subtracted the mean of all WCST and NAB List Learning variables from WRAT-4 Reading within each group, and then compared this difference between groups, obtaining a Hedge's g of -.017, p = .956. Thus, group differences appear to be an artifact of premorbid differences in ability rather than showing increased risk of long term deficits secondary to AFE less than 12. Moreover, 3 AFE less than 12 but zero AFE greater than or equal to 12 subjects had learning disability. Since reading disability and phonologic processing problems are typically evident by second grade [3], it is unlikely that WRAT-4 differences represent acquired impairment for AFE less than 12 (mean AFE = 9, fourth grade). Although potentially difficult to obtain, this can be further confirmed by comparing elementary school achievement test scores for the two groups, prior to playing football, which should also show differences. Premorbid impairments often can be misinterpreted as brain injury effects. [4]
1. Stamm JM, Bourlas AP, Baugh CM, et al. Age of first exposure to
football and later-life cognitive impairment in former NFL players.
Neurology 2015; ; 0: 0-101212000.
2. Lezak MD, Howieson DB, Bigler ED, Tranel D. Neuropsychological
assessment, 5th ed. New York: Oxford University Press; 2012.
3. Fletcher JM, Lyon GR, Fuchs LS, Barnes MA. Learning disabilities. From
identification to intervention. New York: Guilford; 2007.
4. Larrabee GJ, Binder LM, Rohling ML, Ploetz DM. Meta-analytic methods
and the importance of non-TBI factors related to outcome in mild traumatic brain injury: Response to Bigler et al. (2013). Clin Neuropsychol 2013;
27: 215-237.
For disclosures, please contact the editorial office at journal@neurology.org.
Stamm et al. [1] reported poorer cognitive performance for former professional football players starting play before age 12 (age of first exposure (AFE) less than 12) vs. those starting greater than or equal to 12. One variable, WRAT-4 Reading, is often used to estimate premorbid cognitive ability due to its resistance to acquired adult cerebral dysfunction in all but aphasic or significantly demented individuals. [2] Using meta-analysis, we subtracted the mean of all WCST and NAB List Learning variables from WRAT-4 Reading within each group, and then compared this difference between groups, obtaining a Hedge's g of -.017, p = .956. Thus, group differences appear to be an artifact of premorbid differences in ability rather than showing increased risk of long term deficits secondary to AFE less than 12. Moreover, 3 AFE less than 12 but zero AFE greater than or equal to 12 subjects had learning disability. Since reading disability and phonologic processing problems are typically evident by second grade [3], it is unlikely that WRAT-4 differences represent acquired impairment for AFE less than 12 (mean AFE = 9, fourth grade). Although potentially difficult to obtain, this can be further confirmed by comparing elementary school achievement test scores for the two groups, prior to playing football, which should also show differences. Premorbid impairments often can be misinterpreted as brain injury effects. [4]
1. Stamm JM, Bourlas AP, Baugh CM, et al. Age of first exposure to football and later-life cognitive impairment in former NFL players. Neurology 2015; ; 0: 0-101212000.
2. Lezak MD, Howieson DB, Bigler ED, Tranel D. Neuropsychological assessment, 5th ed. New York: Oxford University Press; 2012.
3. Fletcher JM, Lyon GR, Fuchs LS, Barnes MA. Learning disabilities. From identification to intervention. New York: Guilford; 2007.
4. Larrabee GJ, Binder LM, Rohling ML, Ploetz DM. Meta-analytic methods and the importance of non-TBI factors related to outcome in mild traumatic brain injury: Response to Bigler et al. (2013). Clin Neuropsychol 2013; 27: 215-237.
For disclosures, please contact the editorial office at journal@neurology.org.