Physical Performance Is Associated with Working Memory in Older People with Mild to Severe Cognitive Impairment

Table 2

Results of multiple regression analysis with physical performances as predictors (Steps 3 and 4) of working memory and episodic memory after controlling for age, education, level of depression, number of comorbidities, medication, and MMSE (Steps 1 and 2).

Dependent variable	Steps of analysis		Predictor	𝛽	𝑡	Cum 𝑅^2	Incr 𝑅^2
Working memory (𝑛=86)
	Step 1		Age	−0.23	2.12*
			Education	0.26	2.50*
			Depression	−0.22	2.13*
			Comorbidity	−0.04	0.29
			Medications	−0.13	1.10	0.17	0.17*
	Step 2		MMSE	0.61	7.01**	0.49	0.32**
		Step 3	Mobility	0.08	0.77	0.49	0.00
		Step 4	MMSE ∗ mobility	0.18	0.78	0.50	0.00
		Step 3	Balance	0.20	2.02*	0.51	0.03*
		Step 4	MMSE ∗ balance	0.15	0.39	0.52	0.00
		Step 3	Strength	0.31	3.43**	0.56	0.07**
		Step 4	MMSE ∗ strength	0. 81	1.79	0.57	0.01
		Step 3	Aerobic fitness	0.21	2.02*	0.51	0.03*
		Step 4	MMSE ∗ aerobic fitness	0.46	1.22	0.52	0.01
Episodic memory (𝑛=87)
	Step 1		Age	−0.29	2.60*
			Education	0.19	1.82
			Depression	0.07	0.62
			Comorbidity	0.05	0.36
			Medications	0.06	0.46	0.12	0.12
	Step 2		MMSE	0.58	6.20**	0.40	0.29**
		Step 3	Mobility	−0.05	0.45	0.40	0.00
		Step 4	MMSE ∗ mobility	−0.14	0.54	0.41	0.00
		Step 3	Balance	0.14	1.31	0.42	0.01
		Step 4	MMSE ∗ balance	−0.54	1.31	0.43	0.01
		Step 3	Strength	−0.07	0.72	0.41	0.00
		Step 4	MMSE ∗ strength	−0.40	0.76	0.41	0.00
		Step 3	Aerobic fitness	−0.00	0.02	0.40	0.00
		Step 4	MMSE ∗ aerobic fitness	−0.34	0.81	0.41	0.01

Notes: 𝛽: standardized beta coefficient; Cum: cumulative; Incr: increase; MMSE: Mini-Mental State Examination; 𝑡: 𝑡 statistic. ^∗𝑃 value <0.05; ^∗∗𝑃 value <0.01.