A Quick Test of Cognitive Speed (AQT): Usefulness in dementia evaluations in primary care

Figures & data

Table I. Descriptive data shown for the total study group (SG) and subcategorized for patients with cognitive symptoms (CS) and presumed cognitively healthy patients with other medical problems (CH) as primary reason for admission.

Variable	Cognitive symptoms (CS, n = 52)	Cognitively healthy study group (CH, n = 29)	Total (SG, n = 81)	p-value (CS vs. CH)
Men, n (%)	26 (50)	7 (24)	33 (41)	0.023
Woman, n (%)	26 (50)	22 (76)	48 (59)	0.023
Native language, n (%)
Swedish	48 (92)	29 (100)	77 (95)	0.126
Non-Swedish	4 (8)	0 (0)	4 (5)	0.126
Age, (year)	78.2+5.6	75.2+5.5	77.2+5.7	0.024
Range	66–88	65–88	65–88
Education, (year)	9.9+3.7	11.2+3.9	10.4+3.8	0.135
Range	6–16	5–16	5–16
Duration of cognitive symptoms (years)	2.4+1.9	0 (0)	1.5+1.9	0.001
Range	1–9	0–0	0–9
Medical history, n (%)
Hypertension	33 (63)	16 (55)	49 (60)	0.464
Diabetic disease	7 (13)	1 (3)	8 (10)	0.148
Ischaemic heart disease	15 (29)	6 (21)	21 (26)	0.422
Cerebrovascular disease	6 (12)	0 (0)	6 (7)	0.057
Anxiety	4 (7)	0	4 (5)	0.126
Mild depression	6 (12)	1 (3)	7 (9)	0.214
Medical drugs, n (%)
Anxiolytic	12 (23)	4 (14)	16 (20)	0.314
Antidepressants	21 (40)	5 (17)	26 (32)	0.032
Sleeping drugs	17 (33)	5 (17)	22 (27)	0.134
Antipsychotics	4 (8)	0 (0)	4 (5)	0.126
Antihypertensive	40 (77)	18 (62)	58 (72)	0.155
Lipid lowering drugs	25 (48)	11 (38)	36 (44)	0.378
Salicylic acid (low-dose)	26 (50)	10 (34)	36 (44)	0.178
Warfarin	7 (13)	4 (14)	11 (14)	0.967
Insulin	4 (8)	0 (0)	4 (5)	0.126
Anti-diabetic	3 (6)	1 (3)	4 (5)	0.644

Data are shown as mean +/– 1 standard deviation (SD) and range (min–max). P-value analysed by chi-square for gender, medical history, and medical drugs, independent t-test used for age, education, and duration of cognitive symptoms (CS). Significant p-value < 0.05.

Table II. Data showing final diagnosis, cognitive impairment, and no cognitive impairment, for patients with cognitive symptoms and presumed cognitively healthy patients as primary reason for admission.

Variable	Patients with cognitive symptoms (n)	Patients presumed cognitively healthy (n)	Total study group (n)
After evaluation
Cognitive impairment (n)	46	2	48
After evaluation
No cognitive impairment (n)	6	27	33
Total study group (n)	52	29	81

Table III. Patient data categorized by final clinical diagnosis: Listed as total study group (SG), after exclusion of two individuals, patients with cognitive impairment (CI), and patients with no cognitive impairment (NCI).

Variable	Cognitive impairment (CI, n = 46)	No cognitive impairment (NCI, n = 33)	Total study group (SG, n = 79)	p-value (CI vs. NCI)
Men, n (%)	24 (52)	8 (24)	32 (41)	0.013
Woman, n (%)	22 (48)	25 (76)	47 (59)	0.013
Age (year)	80.0+5.1	75.2+5.5	77.4+5.9	0.003
Range	65–88	66–87	65–88
Education (years)	9.7+3.6	11.5+3.9	10.4+3.8	0.037
Range	65–88	66–87	65–88
MMSE (points)	24.9+3.7	28.6+1.4	26.5+3.5	0.001
Range	15–30	25–30	15–30
CDT (points)	4.5+1.0	4.9+0.4	4.7+0.9	0.048
Range	1–5	3–5	1–5
AQT colour (seconds)	40.0+13.9	26.2+4.5	34.2+12.9	0.001
Range	19–102	17–39	17–102
AQT form (seconds)	55.7+19.9	36.3+15.5	47.6+20.5	0.001
Range	26–148	26–118	26–148
AQT colour-form (seconds)	102.9+42.6	71.2+21.5	89.6+38.5	0.001
Range	49–223	49–138	49–223

Data are shown as mean + 1 standard deviation (SD) and range (min–max). P-value analysed by chi-square for gender, independent Student;s t-test for age, education, and the test variables MMSE, CDT, and AQT. Significant p-value < 0.05.

Figure 1. Receiver operating characteristic (ROC) curve. Null hypothesis: true area = 0.5. Area under curve (AUC): AQT = 0.773; MMSE = 0.849; and CDT = 0.574.

Table IV. Different AQT cut-off times analysed by receiver operating characteristics (ROC).

Variable	Sensitivity	1-Specificity
60.5 s	0.913	0.697
62.0 s	0.913	0.667
63.5 s	0.870	0.606
64.5 s	0.848	0.515
66.0 s	0.826	0.394
67.5 s	0.826	0.364
69.0 s	0.808	0.333
70.5 s	0.783	0.333
72.0 s	0.761	0.273
74.0 s	0.739	0.242
77.5 s	0.674	0.182

Data are shown as A Quick Test of Cognitive Speed (AQT); time presented in seconds (s) and sensitivity and 1-specificity as p-values at different cut-offs on the ROC curve.