Table 1.
Demographic characteristics
| Characteristics | N/frequency | |
|---|---|---|
| Sex | ||
| Male | 217 | |
| Female | 2 | |
| Season mean head impact exposure | 238 (s.d. 227) | |
| Test intervals | ||
| Days between pre-season to post-season test (median) | 89 | |
| Days from end of season to post-test (median) | 11 | |
| Race/Ethnicity | % | |
| Native American | 1 | <.01 |
| Asian | 2 | 0.01 |
| African American | 62 | 0.32 |
| Caucasian | 113 | 0.58 |
| Mixed | 9 | 0.05 |
| Total | 187 | 0.96 |
| Missing | 8 | 0.04 |
| Hispanic origin | 8 | 0.04 |
| Psychiatric – Developmental | ||
| Picture Vocabulary Test | 150 | SS = 104.13 (s.d. =13.01) |
| ADHD | 26 | 0.13 |
| Language disability | 1 | 0.01 |
| Reading disability | 7 | 0.04 |
| Writing disability | 2 | 0.01 |
| Math disability | 3 | 0.02 |
| Autism | 2 | 0.01 |
| Taking medication | 15 | 0.08 |
| Average years of contact sport | 1.49 | 3.97 |
| Previous concussions (one persion with two concussions, all the rest =1) | 16 | 0.07 |
| Maternal level of education: | ||
| Less than high school | 1 | 0.01 |
| High-school graduate/GED | 25 | 0.17 |
| Some college | 38 | 0.25 |
| Bachelor’s degree | 49 | 0.32 |
| Master’s degree | 27 | 0.18 |
| Doctoral degree | 7 | 0.05 |
| Professional degree | 4 | 0.03 |
| Total | 151 | 1.00 |
Note. M = mean; s.d. = standard deviation; SS = Standard Score with mean= 100, standard deviation = 15; ADHD = Attention Deficit Hyperactivity Disorder; GED = General Education Diploma.