1. Associations Between Regional Brain Volumes and the NIH-Toolbox Cognition Battery Fluid and Crystallized Composite Scores in Cognitively Healthy Older Adults
SORRELL, Anne; CHAN, Clifford; FALANGOLA, M. Fatima; JENSEN, Jens; HELPERN, Joseph; BENITEZ, Andreana
Center for Biomedical Imaging and Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC
Table 1. Sample characteristics (N=51).
BACKGROUND
The new NIH-Toolbox Cognition Battery (NIHTB-CB) is a series of brief computerized tests of cognitive function across the lifespan. The NIHTB-CB yields composite scores reflecting two major types of cognitive abilities: “fluid” (e.g. rapid information processing, problem-solving, reasoning) and “crystallized” (i.e. knowledge gained from experience and education).1, 2
Crystallized abilities tend to be cumulatively acquired across the lifespan and are preserved through old age, whereas fluid abilities improve rapidly during childhood, peak in early adulthood, and decline with age. Fluid abilities are thought to reflect changes in neurobiological integrity as a function of age and neurological diseases that alter the brain’s structure and function.3
Thus, we hypothesized that the Fluid Composite (FLU), not the Crystallized Composite (CRY), would correlate significantly with measures of brain volume as quantified through the only FDA-approved automated segmentation program (NeuroQuant®).
RESULTS
Lower FLU scores were modestly associated with increased volumes of the lateral and inferior lateral ventricles (r’s= , p< tailed), whereas CRY scores were not associated with any of the volumes of interest (Fig. 2).
These FLU correlations with ventricular volumes were significantly higher than the CRY correlations with ventricular volumes (Hotelling’s t=2.5, p=0.01).
Demographic Characteristics %
Age (Mean ± S.D.)
67.8 ± 5.4
Female
64.7
White
94.1
Years of Education (Mean ± S.D.)
16.6 ± 2.4
NIHTB-CB Composite Scores
(Fully Adjusted Scaled Scores)
Mean ± S.D.
Crystallized Composite
118.2 ± 15.3
Fluid Composite
104.5 ± 13.2
Total Composite
113.6 ± 17.3
NeuroQuant® Volumes
(Percent of Intracranial Volume)
Cortical Gray Matter
30.3 ± 1.2
Cortical White Matter
30.3 ± 1.8
Lateral Ventricles
1.9 ± 1.1
Inferior Lateral Ventricles
0.2 ± 0.1
Hippocampi
0.5 ± 0.1
Figure 2. Significant correlations between FLU and ventricular volumes.
 Crystallized
 Fluid
 Crystallized
 Fluid
Scaled Scores
Lateral Ventricles
(% ICV)
Inferior Lateral Ventricles
(% ICV)
CONCLUSIONS
The NIHTB-CB Fluid Composite is specifically associated with ventricular volumes in a sample of healthy older adults, suggesting that fluid abilities are associated with global brain atrophy in aging.4 These results imply that the NIHTB-CB composite scores may reflect different neurobiological phenomena associated with brain aging.
METHODS
51 cognitively healthy older adults underwent neuro-psychological testing and a brain MRI. NIHTB-CB scores analyzed were FLU and CRY scaled scores fully adjusted for several demographic variables (Table 1). Table 2 lists all of the NIHTB-CB tests that contribute to the composite scores.
T1-MPRAGE images were submitted to NeuroQuant® for volumetric analysis (Fig. 1, Table 1); volumes (in cm3) normalized to intracranial volume were obtained for brain areas known to change with age: cortical gray and white matter, lateral and inferior lateral ventricles, and bilateral hippocampi.
Table 2. NIHTB-CB Tests.
NIHTB-CB Test
Abilities Measured
Composite
Picture Vocabulary Test
Language and auditory word-visual picture matching
Crystallized
Oral Reading Test
Language and written word pronunciation
Dimensional Change Card Sort Test
Executive function and cognitive flexibility
Fluid
Flanker Test of Executive Function
Inhibitory control and attention
Picture Sequence Memory Test
Episodic memory
List Sorting Working Memory Test
Working memory
Pattern Comparison Processing Speed Test
Processing speed
Figure 1. Sample NeuroQuant® General Morphometry Report.
Sample NIHTB-CB Tests
NIHTB-CB Test Administration Set-up
(a) Picture Vocabulary Test
(b) Picture Sequence Memory Test
REFERENCES: 1-Weintraub, S., et al. (2013). Cognition assessment using the NIH Toolbox. Neurology, 80(11 Supplement 3), S54–S64. 2-Mungas, D., et al. (2014). Factor Structure, Convergent Validity, and Discriminant Validity of the NIH Toolbox Cognitive Health Battery (NIHTB-CHB) in Adults. J Int Neuropsychol Soc, 20(6), Akshoomoff, N., et al. (2013). NIH Toolbox Cognitive Function Battery (CFB): Composite Scores of Crystallized, Fluid, and Overall Cognition. Monographs of the Society for Research in Child Development, 78(4), 119– Bugg, J. , et al. (2006). Age differences in fluid intelligence: Contributions of general slowing and frontal decline. Brain and Cognition, 62(1), 9–16.