Table 5.

Multilevel models of 6 year cognitive change as a function of time in study, age, education & cognitive plasticity for CRT and BRT.

CRT Models	Digit Symbol		Letter Series		Word Recall		Verbal Fluency		Vocabulary
Fixed Effects	Estimate	SE	Estimate	SE	Estimate	SE	Estimate	SE	Estimate	SE
Intercept (γ00)	37.42***	0.98	6.97***	0.47	14.70***	0.44	10.59***	0.58	27.92***	0.49
CRT plasticity (γ03)	0.16**	0.06	0.05	0.03	0.01	0.03	−0.00	0.04	−0.00***	0.03
Slope (γ10)	0.37	0.22	0.00	0.07	0.09	0.10	−0.01	0.13	−0.01	0.06
CRT plasticity (γ13)	−0.01	0.01	0.00	0.00	−0.00	0.01	−0.00	0.01	0.00	0.00
Random Effects
Intercept (u0i)	51.91***	5.48	13.36***	1.26	10.56***	1.11	17.47***	1.90	15.06***	1.35
Slope (u1i)	0.64**	0.24	0.00	0.03	0.20***	0.05	0.16*	0.08	0.02**	0.01
Covariance	1.97*	0.85	0.04	0.14	0.42*	0.18	0.21	0.30	−0.10	0.12
Residual (eij)	24.27***	1.27	3.50***	0.18	4.87***	0.25	9.27***	0.48	2.42***	0.13

BRT Models	Digit Symbol		Letter Series		Word Recall		Verbal Fluency		Vocabulary
Fixed Effects	Estimate	SE	Estimate	SE	Estimate	SE	Estimate	SE	Estimate	SE
Intercept (γ00)	37.50***	0.91	7.04***	0.45	14.76***	0.43	10.65***	0.57	27.96***	0.49
BRT plasticity (γ03)	0.06***	0.01	0.03***	0.00	0.02***	0.00	0.02*	0.01	0.01	0.01
Slope (γ10)	0.37	0.22	0.00	0.07	0.09	0.10	−0.01	0.13	−0.01	0.06
BRT plasticity (γ13)	−0.00	0.00	0.00	0.00	0.00	0.00	−0.00	0.00	0.00	0.00
Random Effects
Intercept (u0i)	46.83***	5.07	11.77***	1.14	9.97***	1.06	17.02***	1.87	14.90***	1.33
Slope (u1i)	0.63**	0.24	0.00	0.03	0.19***	0.05	0.16*	0.08	0.02**	0.01
Covariance	2.06*	0.81	−0.02	0.13	0.39*	0.18	0.24	0.30	−0.13	0.12
Residual (eij)	24.28***	1.27	3.50***	0.18	4.87***	0.25	9.27***	0.48	2.41***	0.12

NOTE: For all multilevel analyses, age was centered at 75 years and education was categorized as > or ≤ 12 years of formal education.

γ₀₀ = average cognitive performance for a 75 year-old individual with ≤12 years of education at Year-1; ≤₀₃ = average difference in cognitive performance for a 1-unit increase in plasticity (CRT plasticity, BRT plasticity) at year 1; ≤₁₀ = average amount of cognitive change per year increase of being in the study; ≤₁₃ = average difference in rate of change associated with a 1-unit increase in time in study with a 1-unit increase in plasticity (CRT plasticity, BRT plasticity); u_0i = between-person variance in the intercept of cognitive ability; u_1i = between-person variance in the slope of cognitive ability; e_jj = within-person variance.

^*p<0.05;

^**p<0.01;

^***p<0.001