Table 5.

Summary of regression models examining the effect of P-tau severity on atrophy in the brain donors with CTE

	Effects of p-tau severity on atrophy
Measures of atrophy	Standardized beta	Standard error	P-value
aVisually rated MRI global atrophy	0.68	0.22	<0.01
Frontal lobes	0.30	0.15	0.047
Temporal lobes	0.23	0.15	0.15
Posterior lobes	0.08	0.15	0.62
Medial temporal lobes	0.25	0.21	0.25

A summary composite of semi-quantitative ratings of p-tau (0 [none]–3 [severe] scale) across 14 cortical and subcortical brain regions was computed⁷ and served as the independent variable. A global composite of MRI atrophy was calculated, based on the sum of frontal (orbital-frontal cortex, dorsolateral frontal cortex, superior frontal cortex), anterior temporal, posterior (parietal, occipital), and MTL visual MRI ratings of atrophy. P-tau severity was assessed in the following regions that mapped onto lobes visually rated for atrophy on MRI: frontal cortex (dorsolateral frontal cortex + inferior frontal cortex), superior temporal cortex, inferior parietal cortex, and hippocampus (CA1+CA2+CA4)

^aThe primary analyses included linear regression models that tested the association between global-based composites to limit the number of analyses and to increase statistical power. Exploratory linear regression analyses examined regional correspondence between p-tau severity and the MRI ratings of atrophy. Analyses controlled for age at death and time since MRI