Table 9.

Multilevel models examine the interaction between aperiodic exponent and individual peak α frequency

Predictors	Episodic memory			Executive functioning			BTACT
Predictors	Estimates	95% CI	p	Estimates	95% CI	p	Estimates	95% CI	p
Intercept (M2)	−0.43	−0.60 to −0.25	<0.001	−0.07	−0.19 to 0.05	0.228	−0.13	−0.24 to −0.02	0.024
MIDUS wave	−0.12	−0.25 to 0.01	0.069	−0.41	−0.49 to −0.34	<0.001	−0.37	−0.44 to −0.30	<0.001
Exponent	0.06	−0.41 to 0.53	0.802	0.13	−0.19 to 0.45	0.417	0.13	−0.17 to 0.42	0.393
IAPF	0.07	−0.06 to 0.20	0.269	0.02	−0.07 to 0.11	0.634	0.03	−0.05 to 0.11	0.482
Age	−0.02	−0.03 to −0.01	<0.001	−0.02	−0.03 to −0.02	<0.001	−0.02	−0.03 to −0.02	<0.001
Sex	0.73	0.52 to 0.94	<0.001	0.11	−0.03 to 0.26	0.135	0.22	0.08 to 0.35	0.002
Education	0.17	0.05 to 0.30	0.007	0.14	0.06 to 0.22	0.001	0.14	0.07 to 0.22	<0.001
Lag between waves	−0.09	−0.21 to 0.02	0.116	−0.21	−0.29 to −0.13	<0.001	−0.20	−0.27 to −0.12	<0.001
Wave × exponent	0.09	−0.39 to 0.58	0.714	−0.08	−0.36 to 0.19	0.546	−0.03	−0.29 to 0.23	0.826
Wave × IAPF	0.07	−0.06 to 0.20	0.314	0.06	−0.02 to 0.13	0.146	0.06	−0.01 to 0.13	0.118
Exponent × IAPF	−0.07	−0.51 to 0.38	0.773	−0.15	−0.44 to 0.15	0.327	−0.14	−0.42 to 0.13	0.316
Wave × exponent × IAPF	0.20	−0.26 to 0.67	0.397	0.34	0.07 to 0.61	0.013	0.33	0.08 to 0.59	0.010
Random effects
σ²	0.47			0.15			0.13
τ₀₀	0.38 _M2ID			0.23 _M2ID			0.19 _M2ID
ICC	0.44			0.60			0.59
N	234 _M2ID			235 _M2ID			234 _M2ID
Observations	451			458			443
Marginal R²/conditional R²	0.202/0.557			0.302/0.722			0.323/0.724

Repeated measured cognitive data nested within participant, indicated by M2ID. Sex coded as 0 = male, 1 = female. Education coded as −1 = high school or less, 0 = some college, 1 = bachelor's degree or higher. MIDUS wave coded as 0 = MIDUS 2, 1 = MIDUS 3. Years between waves (i.e., between MIDUS 2 and MIDUS 3 Cognitive Projects) and age at M2 Neuroscience Project are mean centered. Empirical Bayes slope estimation used (Bates et al., 2015).
Bold values are significant at p < .05.