Table 3.
Within Football (n = 59) Association of Baseline Whole Hippocampus and Subfield Volumes (in mm3) with the Presence of Past Concussions, the Position-Based Concussion Risk, the Years of Tackle Football Experience Before Baseline, and Baseline SCAT Score
| Past concussions (n = 22 with past concussion) | Position-based concussion risk | Years of tackle football | SCAT score | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Adjusted difference in mm3 (95% CI) | T (p value) | R2 | Volume change (mm3) for position-based risk increase (95% CI) | T (p value) | R2 | Volume change (mm3) per year (95% CI) | T (p value) | R2 | Volume change (mm3) per 1 unit change in SCAT score (95% CI) | T (p value) | R2 | |
| Hippocampus | –229.71 (−711.42, 252.01) | –0.96 (0.343) | 0.29 | –28.67 (−55.84, −1.50) | –2.12 (0.039) | 0.33 | –1.94 (−90.31, 86.44) | –0.04 (0.965) | 0.26 | –18.21 (−89.49, 53.07) | –0.51 (0.611) | 0.28 |
| Dentate gyrus | –122.37 (−244.53, −0.21) | –2.01 (0.050) | 0.17 | –4.09 (−10.52, 2.34) | –1.28 (0.208) | 0.13 | -12.40 (−35.77, 10.98) | –1.06 (0.292) | 0.13 | –11.89 (−29.18, 5.40) | –1.38 (0.174) | 0.15 |
| CA1 | –58.53 (−228.20, 111.13) | –0.69 (0.492) | 0.17 | –7.74 (−16.38, 0.90) | –1.80 (0.078) | 0.20 | 0.45 (−32.07, 32.98) | 0.03 (0.978) | 0.16 | –6.46 (−27.19, 14.28) | –0.62 (0.535) | 0.16 |
| Subiculum | –41.92 (−101.35, 17.51) | –1.41 (0.163) | 0.13 | –5.65 (−8.79, −2.52) | –3.61 (<0.001)a | 0.29 | 0.83 (−9.58, 11.24) | 0.16 (0.873) | 0.09 | 0.53 (−5.86, 6.93) | 0.17 (0.868) | 0.10 |
| Entorhinal-perirhinal | –6.89 (−255.39, 0.00) | –0.06 (0.956) | 0.28 | –11.18 (−28.43, 6.07) | –1.30 (0.199) | 0.31 | 9.18 (−38.84, 57.19) | 0.38 (0.703) | 0.27 | –0.39 (−40.03, 39.24) | –0.02 (0.984) | 0.28 |
A negative difference/coefficient means decreased volumes in football are associated with the presence of past concussion, with increased concussion risk (measured in units of concussions per 100,000 position plays), with increased years of previous tackle football, and with increasing baseline SCAT score, using age and total intracranial volume as covariates. Of the 22 with past concussions, 2 subjects had two past concussions, and 1 subject had three past concussions.
Meets multiple comparison correction across subfields by false discovery rate.
Bold highlights p < .05.
SCAT, Standardized Concussion Assessment Tool; CA1, cornu ammonis area 1; CI, confidence interval.