. Author manuscript; available in PMC: 2018 Jan 1.

Published in final edited form as: J Alzheimers Dis. 2017;59(4):1427–1437. doi: 10.3233/JAD-170116

Table 4.

Spearman’s r correlations (p-values) between driving summary variables (per day) and domain-specific cognitive z-scores; n = 28

	Executive function	Attention	Memory	Working memory	Visuospatial
Variable
Mean distance driven per day (miles)	0.54	0.49	0.38	NS	NS
Mean distance driven per day (miles)	0.003^**	<0.01^**	0.045^*
Day-to-day variability in distance driven	0.49	NS	0.42	NS	0.40
Day-to-day variability in distance driven	<0.01^**		0.03^*		<0.05^*
Mean time driven per day (min)	0.49	NS	NS	NS	NS
Mean time driven per day (min)	<0.01^**
Day-to-day variability in time driven	0.42	0.38	0.38	NS	NS
Day-to-day variability in time driven	0.03^*	<0.05^*	<0.05^*
Day-to-day variability in first start time	NS	NS	0.47	NS	NS
Day-to-day variability in first start time			0.02
% of driving days ≥ 20 miles	0.49	0.44	NS	NS	NS
% of driving days ≥ 20 miles	<0.01^**	0.02^*
Mean time of highway driving per day (s)	0.59	0.46	0.43	0.40	0.50
Mean time of highway driving per day (s)	0.001^**	0.02^*	0.02^*	0.04^*	0.01^*

p < 0.05;

^**

p < 0.01.

NS, not significant; p = 0.0014 after adjusting for multiple comparisons.