Table 4.

Correlations between cognitive and physical measures and ERPs.

Test	Older adults					Young adults
	Variable	r	p	99% CI	95% CI	r	p	99% CI	95% CI
Executive function PC	sMMR (age)	0.299*	0.004	0.001 to 0.594	0.035 to 0.524	ns	ns	ns	ns
	sP3a	0.239	0.017	−0.062 to 0.517	0.003 to 0.468	ns	ns	ns	ns
	Six-minute walk distance (age, edu)	0.203	0.036	−0.076 to 0.443	0.011 to 0.395	—	—	—	—
Error susceptibility PC	sMMR (edu, age)	−0.276	0.007	−0.491 to 0.021	−0.465 to −0.055	ns	ns	ns	ns
Explicit memory PC	aP2 (age, edu)	0.254	0.012	−0.025 to 0.508	0.025 to 0.439	ns	ns	ns	ns
Working memory PC	aMMN	ns	ns	ns	ns	0.479*	0.001	0.045 to 0.756	0.184 to 0.689
Six-minute walk distance	sP3a (age)	0.319*	0.002	0.062 to 0.548	0.131 to 0.502	—	—	—	—
	Executive function PC (age, edu)	0.284	0.006	−0.050 to 0.531	0.059 to 0.490	—	—	—	—
	sMMR (edu)	0.203	0.036	−0.076 to 0.443	0.011 to 0.395	—	—	—	—
Tapping speed – dominant hand	sP3a	0.272	0.008	−0.009 to 0.533	0.034 to 0.478	ns	ns	ns	ns
	sMMR	0.215	0.028	−0.064 to 0.463	0.017 to 0.393	ns	ns	ns	ns
	aMMN (age)	−0.229	0.021	−0.477 to 0.033	−0.417 to −0.032	0.417	0.005	−0.026 to 0.715	0.116 to 0.658
Tapping speed – non-dominant hand	sP3a (age)	0.298	0.004	−0.019 to 0.600	0.067 to 0.520	ns	ns	ns	ns
	aN1 (age)	−0.252	0.013	−0.481 to 0.009	−0.436 to −0.058	ns	ns	ns	ns
	aMMN	ns	ns	ns	ns	0.387	0.008	−0.049 to 0.668	0.087 to 0.622

Variables that show correlation at least in one of the groups within 95% CI are listed; those showing significant correlation within 99% CI are marked with *. Age and/or education (edu) in parentheses refers to significant partial correlations after controlling for the mentioned variable. r, Pearson’s correlation coefficient (bootstrap statistics with 1000 iterations); p, significance (one-tailed); CI, confidence interval; ns, non–significant; −, not measured within the young adult group.