Investigating whether fractional anisotropy is associated with reduced reaction time cost on an attentional control task: Neuroimaging / multi‐modal comparisons. (7th December 2020)

• Record Type: Journal Article
• Authors: McKay, Nicole Sarah; Gordon, Brian A.; Strain, Jeremy F; Wang, Qing; Morris, John C.; Balota, David A.; Benzinger, Tammie L.S.
• Is Part Of: Alzheimer's & dementia. Volume 16(2020)Supplement 4
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-07
• Subjects: Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1002/alz.046462
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Background: Previous research has shown that with age and disease, the integrity of white matter (WM) structures can decline. One such measure of WM integrity is fractional anisotropy (FA), where lower values are often associated with disrupted WM. Similarly, previous work has highlighted that attentional control also declines with age and disease. It was therefore of interest to investigate whether FA was associated with cognitive ability in an aging population. To assess this, we derived a measure of attentional control performance from the Consonant‐Vowel, Odd‐Even (CVOE) task. Method: 246 participants aged 42‐87 years ( M = 69, SD = 8.5), who were enrolled in studies at the Knight ADRC, were included in this analysis. Participants were classified as cognitively normal (CDR = 0, n = 185), or cognitively impaired (CDR > 0, n = 61). All participants completed an MRI, and the CVOE task. Tract‐Based Spatial Statistics (TBSS) were run on FA maps calculated for the participants. We used reaction time (RT) cost, the burden caused by the most difficult aspects of this task, as our behavioral measure of interest. This measure was calculated as the difference between RTs on congruent vs incongruently ordered trials. Result: Using TBSS, we found that the relationships between FA and RT‐cost were significantly different for each group (Figure 1). More specifically, we found no relationship between RT‐cost and FA in our cognitively normal individuals ( r = 0.14, p = 0.052; Figure 2). In contrast, we do observe a significant negative relationship between RT‐cost and FA in our cognitively impaired individuals ( r = ‐0.64, p < 0.01; Figure 3). Conclusion: Overall, we found a strong relationship between WM integrity and cognitive performance, as measured by the CVOE task. That is, as integrity becomes more compromised, participants become slower at switching between trial types within the CVOE task. Importantly, this relationship is only observed for individuals who are cognitively impaired. Taken together, our results add to a body of literature that report a relationship between WM integrity and cognitive performance, but hint that further development of more sensitive cognitive tasks may be needed to fully understand this relationship.