Current Gerontology and Geriatrics Research

Research Article

Intraindividual Variability in Domain-Specific Cognition and Risk of Mild Cognitive Impairment and Dementia

Table 1

Means (SDs) of the raw and standardized scores for the cognitive measures at baseline, standardized scores for executive function, verbal episodic memory, overall cognition, IAV Cognitive Domains, and IAV Time for WHISCA participants by group.


Means (SDs)
Cognitive domain	All ()	No impairment ()	MCI	value	Probable dementia	value	MCI or probable dementia ()	value

PMA vocabulary	36.93 (9.580)	37.24 (9.420)	31.19 (10.56)	<0.0001	31.00 (10.44)	<0.0001	30.86 (10.64)	<0.0001
Letter fluency	40.03 (12.35)	40.18 (12.27)	37.47 (13.57)	0.0639	37.82 (14.50)	0.2050	37.15 (13.51)	0.0162
Category fluency	29.15 (6.215)	29.37 (6.168)	24.07 (4.922)	<0.0001	25.44 (6.298)	<0.0001	24.91 (5.589)	<0.0001
*BVRT	6.915 (3.675)	6.755 (3.579)	9.838 (4.122)	<0.0001	10.36 (4.483)	<0.0001	10.01 (4.151)	<0.0001
CVLT (learning)	29.03 (6.174)	29.34 (6.009)	23.05 (5.527)	<0.0001	22.00 (6.931)	<0.0001	23.03 (6.308)	<0.0001
CVLT (short-delay free recall)	8.587 (3.018)	8.756 (2.925)	5.365 (2.672)	<0.0001	4.822 (3.284)	<0.0001	5.287 (2.923)	<0.0001
CVLT (long-delay free recall)	9.334 (2.975)	9.488 (2.893)	6.203 (2.669)	<0.0001	6.022 (3.583)	<0.0001	6.337 (2.984)	<0.0001
Digits forward	7.484 (2.059)	7.524 (2.066)	6.608 (1.719)	<0.0001	6.978 (1.738)	0.0789	6.713 (1.751)	<0.0001
Digits backward	6.723 (2.022)	6.765 (2.029)	6.041 (1.716)	0.0025	5.867 (1.590)	0.0005	5.891 (1.696)	<0.0001
Card rotations	56.38 (26.94)	57.13 (26.81)	43.78 (24.26)	<0.0001	36.89 (26.25)	<0.0001	41.66 (25.30)	<0.0001
Finger tapping (dominant)	38.57 (7.561)	38.67 (7.566)	36.64 (7.242)	0.0237	38.00 (6.801)	0.5583	36.71 (7.245)	0.0113
Finger tapping (nondominant)	36.46 (6.417)	36.58 (6.419)	34.11 (6.080)	0.0012	35.32 (5.915)	0.1931	34.14 (5.955)	0.0002

Standardized total score (-scores): verbal fluency, CVLT, digits forward and backward, and fine motor speed
Verbal fluency	−0.046 (0.952)	−0.019 (0.945)	−0.633 (0.873)	<0.0001	−0.490 (1.009)	0.0010	−0.570 (0.932)	<0.0001
CVLT	0.024 (0.932)	0.076 (0.902)	−1.01 (0.813)	<0.0001	−1.11 (1.104)	<0.0001	−0.988 (0.926)	<0.0001
Digits forward and backward	−0.017 (0.993)	0.006 (0.997)	−0.446 (0.805)	<0.0001	−0.396 (0.718)	0.0006	−0.460 (0.787)	<0.0001
Fine motor speed	−0.102 (1.085)	−0.084 (1.085)	−0.456 (1.037)	0.0038	−0.246 (0.995)	0.3216	−0.449 (1.028)	0.0010

Standardized scores (-scores): executive function, verbal episodic memory, and overall cognition
Executive function	−0.038 (0.978)	−0.008 (0.976)	−0.661 (0.816)	<0.0001	−0.544 (0.862)	0.0003	−0.633 (0.839)	<0.0001
Verbal episodic memory	0.024 (0.932)	0.076 (0.902)	−1.01 (0.813)	<0.0001	−1.11 (1.104)	<0.0001	−0.988 (0.926)	<0.0001
Overall cognition	−0.128 (0.962)	−0.077 (0.938)	−1.10 (0.887)	<0.0001	−1.12 (0.906)	<0.0001	−1.11 (0.902)	<0.0001

IAV Cognitive Domains (standard deviation across cognitive domains at baseline)
SD	0.806 (0.260)	0.804 (0.259)	0.811 (0.272)	0.8182	0.917 (0.288)	0.0042	0.843 (0.269)	0.1475

IAV time (slope of IAV Cognitive Domains across measurement occasions)
Slope SD	0.003 (0.519)	−0.009 (0.512)	0.221 (0.600)	0.0017	0.281 (0.594)	0.0002	0.237 (0.604)	0.0001

Note. PMA vocabulary: primary mental abilities vocabulary (total correct − 1/3 number incorrect); letter fluency: letter fluency (number correct); category fluency: category fluency (number correct); BVRT: Benton Visual Retention Test (total figures with errors); CVLT (learning): California Verbal Learning Test (number correct 3 list A trials); CVLT (short-delay free-recall): California Verbal Learning Test (number correct list A short-delay free recall); CVLT (long-delay free-recall): California Verbal Learning Test (number correct list A long-delay free-recall); digits forward: digit span forward (number correct); digits backward: digit span backward (number correct); card rotations: card rotations (total correct − total incorrect); finger tapping (dominant): finger tapping test (taps for dominant hand); finger tapping (nondominant): finger tapping test (taps for nondominant hand); *higher scores reflect poorer performance.