(a).

Memory function subtest scores		Before intervention	After intervention	Improvement relative to baseline (= 1)	t	P
Audio/visual memory	BrainPower	2.28 ± 1.06	3.43 ± 0.83	1.50	−8.247	<0.001
	Placebo	2.51 ± 0.81	3.41 ± 1.00	1.36	−5.014	<0.001
	t	−1.232	0.074
	P	0.221	0.941
Abstracting ability	BrainPower	2.40 ± 1.08	3.45 ± 0.75	1.44	−6.602	<0.001
	Placebo	2.73 ± 1.08	3.47 ± 0.92	1.27	−4.791	<0.001
	t	−1.474	0.081
	P	0.144	0.889
Memory retrieval	BrainPower	2.17 ± 1.15	2.81 ± 0.92	1.29	−3.526	0.001
	Placebo	2.18 ± 1.14	2.47 ± 0.83	1.13	−1.820	0.075
	t	−.027	0.410
	P	0.979	0.060