Table 2.

Comparisons of Patients and Healthy Comparison Subjects on the Standard Neuropsychologic Battery

Measure	Patients (N = 123) Mean (SD)	Healthy subjects (N = 36) Mean (SD)	t value
Attention/motor
Trail Making Test (A)
Response time (sec)	27.6 (8.3)	28.3 (8.6)	t = 0.48, ns
Digit Span
Numbers recalled	11.0 (2.6)	10.8 (2.8)	t = 0.28, ns
Continuous Performance Test
d′ verbal	1.9 (0.9)	2.0 (0.8)	t = 0.85, ns
d′ visual	1.6 (0.7)	1.6 (0.8)	t = 0.43, ns
Digit Symbol
Number of symbols	60.2 (10.3)	62.2 (9.7)	t = 1.05, ns
Memory/learning^a
Wechsler Memory Scale, Visual Reproduction
Immediate recall^b	35.7 (3.2)	34.3 (3.2)	t = 2.25, p = .03
Delayed recall^b	34.8 (3.6)	31.7 (5.5)	t = 3.11, p = .03
Hopkins Verbal Learning Test
Trial 1	6.5 (0.9)	6.1 (2.02)	t = 0.96, ns
Trial 2	9.2 (1.6)	8.4 (2.0)	t = 2.33, p = .02
Trial 3	10.2 (1.4)	9.4 (1.8)	t = 2.35, p = .03
Delayed recall	9.3 (2.0)	7.2 (3.5)	t = 3.07, p = .004
Discrimination index	10.8 (1.1)	10.0 (2.1)	t = 1.73, ns
Executive
Trial Making Test (B)
Response time (sec)	58.02 (16.9)	60.01 (16.7)	t = 0.61, ns
Halstead–Reitan Categories Test	43.2 (26.9)	45.5 (23.2)	t = 0.44, ns
Verbal fluency
Words generated	40.5 (10.7)	43.3 (9.7)	t = 1.36, ns
Wisconsin Card Sort Test
Categories^b	5.1 (1.4)	5.6 (0.9)	t = 2.24, p = .03
Errors	29.5 (18.0)	24.0 (16.2)	t = 1.61, ns
Perseverative responses^b	16.2 (11.5)	11.5 (7.9)	t = 2.39, p = .02
Perseverative errors^b	13.2 (6.5)	10.6 (4.7)	t = 2.23, p = .03
Failure to maintain set^b	1.0 (1.2)	0.5 (0.7)	t = 2.01, p = .05
Learning to learn^b	–0.5 (3.2)	0.2 (2.2)	t = 2.59, p = .02

Higher scores indicate better performance. Depressed subjects reported no deficits and actually performed better than healthy subjects.

Log transformation (base 10) of data performed before analysis.