Table 3

Performance of groups on cognitive tests at the initial evaluation by final diagnosis

Tests Mean (SD), range	Developing dementia	Stable QD	Significance Mann-Whitney U (two tailed)*	Significance χ^2†
*Mann-Whitney U analysis conducted to compare groups on continuous predictor variables;
†χ² analysis conducted to compare groups on predictor variables recoded to categorical variables (above and below the 5th centile rank).
Working memory, abstraction, problem solving
Digit span-forwards (max 14)	8.2 (2.4), 4–13, n=37	8.4 (2.6), 4–14, n=90	0.691
Digit span-backwards (max 14)	6.1 (2.5), 2–13, n=37	6.7 (2.2), 2–14, n=90	0.128
Similarities (max 28)	13.4 (7.1), 0–26, n=37	16.0 (6.3), 0–27, n=91	0.046	0.424
Picture completion (max 20)	12.3 (4.5), 2–18, n=37	13.3 (4.4), 3–19, n=91	0.251	0.305
Episodic memory
Story recall-immediate (max 56)	11.6 (9.9), 0–37, n=37	18.8 (10.8), 0–47, n=91	0.001	0.000
Story recall-delayed (max 56)	6.0 (10.1), 0–37, n=37	13.8 (12.6), 0–45, n=91	0.001	0.001
Percentage story retained (del/imm×100)	31.7 (38.0), 0–100, n=37	58.1 (42.4), 0–155.6, n=91	0.001	0.001
Visual recognition (max 10)	7.8 (2.4), 0–10, n=37	8.8 (2.2), −1–10, n=92	0.015	0.003
Verbal learning-learning index (max 1.0)	0.15 (0.10), 0–0.42, n=32	0.23 (0.16), 0–0.90, n=84	0.003	0.146
HVLT total list recall (max 36)	14.2 (5.6), 3–26, n=32	17.8 (4.6), 7–30, n=86	0.001	0.021
Verbal recognition (max 12)	7.3 (2.7), 0–11, n=31	9.6 (2.2), 0–12, n=85	0.001	0.004
Language and executive function
Frenchay Aphasia Screening Test (max 15)	14.3 (0.7), 13–15, n=35	14.3 (0.9), 11–15, n=89	0.917	0.828
Verbal fluency	36.6 (11.5), 9–56, n=36	41.1 (11.1), 18–69, n=87	0.044	0.145
Weigl’s colour form sorting (max 4)	3.5 (0.8), 1–4, n=35	3.6 (0.8), 1–4, n=92	0.676	0.588
Cognitive speed
Digit copy-age scaled score (max 210)	102.9 (20.5), 53–151, n=37	106.5 (20.1), 60–155, n=86	0.384	0.510
Visuospatial function
Cube analysis (max 10)	9.2 (1.3), 4–10, n=37	9.4 (1.5), 0–10, n=91	0.398	0.896