Table 1.

Participant characteristics, clock drawing, and driving outcomes

	Healthy controls (n = 47)	Alzheimer's disease (n = 75)
Age	71.87 (7.77)	76.65 (6.24)*
Gender (%, M/F)	61.7/38.3	53.3/46.7
Education	16.30 (3.78)	13.53 (3.28)*
MMSE	29.48 (0.65)	25.05 (2.83)*
CDR sum of boxes	0.00 (0.00)	2.76 (1.60)*
Visual acuity (≥20/20)	45%	15%*
7-point system	5.61 (1.07)	4.16 (1.67)**
8-point system	7.43 (1.06)	6.05 (2.08)**
10-point system	9.17 (.94)	7.52 (2.20)**
Conceptualization error	10.60%	43.80%**
Driving experience (years)	53.11 (6.80)	56.28 (9.23)*
Miles driven/week	195.53 (114.87)	87.64 (88.20)**
Road test error rate	0.04 (0.03)	0.09 (0.07)**
Unsafe driver ratings	14.90%	54.70%**

Notes: Values are means (SD) unless otherwise noted; MMSE = Mini-Mental State Examination; CDR = Clinical Dementia Rating Scale.

*p < .05.

**p < .001.