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2 Cognitive Heterogeneity and Risk of Progression in Data-Driven Subtle Cognitive Decline Phenotypes
- Kelsey R Thomas, Katherine J Bangen, Alexandra J Weigand, Gema Ortiz, Kayla S Walker, David P Salmon, Mark W Bondi, Emily C Edmonds
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 103-104
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Objective:
There is increasing recognition of cognitive and pathological heterogeneity in early-stage Alzheimer’s disease and other dementias. Data-driven approaches have demonstrated cognitive heterogeneity in those with mild cognitive impairment (MCI), but few studies have examined this heterogeneity and its association with progression to MCI/dementia in cognitively unimpaired (CU) older adults. We identified cluster-derived subgroups of CU participants based on comprehensive neuropsychological data and compared baseline characteristics and rates of progression to MCI/dementia or a Dementia Rating Scale (DRS) of <129 across subgroups.
Participants and Methods:A hierarchical cluster analysis was conducted using 11 baseline neuropsychological test scores from 365 CU participants in the UCSD Shiley-Marcos Alzheimer’s Disease Research Center (age M=71.93 years, SD=7.51; 55.9% women; 15.6% Hispanic/Latino/a/x/e). A discriminate function analysis was then conducted to test whether the individual neuropsychological scores predicted cluster-group membership. Cox regressions examined the risk of progression to consensus diagnosis of MCI or dementia, or to DRS score <129, by cluster group.
Results:Cluster analysis identified 5 groups: All-Average (n=139), Low-Visuospatial (n=46), Low-Executive (n=51), Low-Memory/Language (n=83), and Low-All Domains (n=46). The discriminant function analysis using the neuropsychological measures to predict group membership into these 5 clusters correctly classified 85.2% of the participants. Subgroups had unique demographic and clinical characteristics. Relative to the All-Average group, the Low-Visuospatial (hazard ratio [HR] 2.39, 95% CI [1.03, 5.56], p=.044), Low-Memory/Language (HR 4.37, 95% CI [2.24, 8.51], p<.001), and Low-All Domains (HR 7.21, 95% CI [3.59, 14.48], p<.001) groups had greater risk of progression to MCI/dementia. The Low-Executive group was also twice as likely to progress to MCI/dementia compared to the AllAverage group, but did not statistically differ (HR 2.03, 95% CI [0.88,4.70], p=.096). A similar pattern of results was found for progression to DRS score <129, with the Low-Executive (HR 2.82, 95% CI [1.26, 6.29], p=.012), Low-Memory/Language (HR 3.70, 95% CI [1.80, 7.56], p<.001) and Low-All Domains (HR 5.79, 95% CI [2.74, 12.27], p<.001) groups at greater risk of progression to a DRS score <129 than the All-Average group. The Low-Visuospatial group was also twice as likely to progress to DRS <129 compared to the All-Average group, but did not statistically differ (HR 2.02, 95% CI [0.80, 5.06], p=.135).
Conclusions:Our results add to a growing literature documenting heterogeneity in the earliest cognitive and pathological presentations associated with Alzheimer’s disease and related disorders. Participants with subtle memory/language, executive, and visuospatial weaknesses all declined at faster rates than the All-Average group, suggesting that there are multiple pathways and/or unique subtle cognitive decline profiles that ultimately lead to a diagnosis of MCI/dementia. These results have important implications for early identification of individuals at risk for MCI/dementia. Given that the same classification approach may not be optimal for everyone, determining profiles of subtle cognitive difficulties in CU individuals and implementing neuropsychological test batteries that assess multiple cognitive domains may be a key step towards an individualized approach to early detection and fewer missed opportunities for early intervention.
3 Type 2 Diabetes Moderates the Association between Amyloid PET and Attention/Executive Functioning in Older Veterans
- Rachel Membreno Almendares, Katherine J Bangen, Monica T Ly, Kayla S Walker, Sunder Mudaliar, Kelsey R Thomas
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 104-105
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Objective:
Type 2 diabetes (T2D) is a risk factor for cognitive impairment/dementia and has been shown to modify the impact of Alzheimer’s disease (AD) biomarkers on cognition and everyday functioning. Studies examining amyloid-ß (Aß), one of the hallmark AD pathologies, have shown mixed results regarding associations of Aß biomarkers with cross-sectional cognition as well as T2D, though Aß is generally associated with future cognitive declines. The purpose of the present study is to examine whether T2D impacts the associations between amyloid positron emission tomography (PET) and cognition in older Veterans.
Participants and Methods:The current study included 202 mostly male Vietnam-Era Veterans from the Department of Defense-Alzheimer’s Disease Neuroimaging Initiative (DOD ADNI) study (age M=69.38 years, SD=4.37; 40% with self-reported T2D) who completed neuropsychological testing and florbetapir PET imaging. The Aß PET standardized uptake variable ratio (SUVR) was measured using a previously-validated summary SUVR calculated by dividing the mean uptake across 4 AD-vulnerable cortical regions by whole cerebellar uptake. General linear models examined whether T2D moderated the relationship of Aß PET with memory, attention/executive functioning, and language composite scores. Models adjusted for age, education, apolipoprotein E e4 carrier status, vascular risk burden, depressive symptoms, post-traumatic stress disorder (PTSD) symptom severity, and history of traumatic brain injury (TBI).
Results:There was no main effect of diabetes on memory, attention/executive functioning, or language performance, and higher Aß PET SUVR was only associated with worse attention/executive functioning performance (ß=-.146, 95% CI [-.261, -.031], p=.013). The Aß PET x T2D interaction was significant for attention/executive functioning such that higher Aß PET SUVR was associated with lower attention/executive functioning scores, but only in those with T2D (ß=-.116, [-.225, -.006], p=.038). This interaction was not significant for language or memory.
Conclusions:The results show that Aß may negatively impact attention/executive functioning, but this effect was only found in Veterans with T2D. Prior work has suggested that T2D may be more associated with tau biomarkers than markers of Aß, so it is possible that the current results are due to a compounding effect of Aß pathology plus microvascular and/or tau pathology. Notably, the sample was relatively young, a relatively large proportion had elevated PTSD symptoms and/or a TBI history (which have both been shown to relate to attention/executive function), and the measures that made up the attention/executive composite (Trail Making Test A and B) have been shown to be particularly sensitive - all of which may have contributed to the domain-specific effects. Future research is needed to investigate the role that tau and vascular pathology may play in cognition among individuals with T2D. Longitudinal studies are also needed to better understand the timing and progression of these relationships.
56 TBI Severity Moderates the Association between Subjective and Objective Attention in Older Veterans
- Peter P Rantins, Monica Ly, Alexandra L Clark, Alexandra J Weigand, Kayla S Walker, Victoria C Merritt, Katherine J Bangen, Kelsey R Thomas
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- Journal:
- Journal of the International Neuropsychological Society / Volume 29 / Issue s1 / November 2023
- Published online by Cambridge University Press:
- 21 December 2023, pp. 363-364
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Objective:
Prior work on associations between self-reported cognition and objective cognitive performance in Veterans has yielded mixed findings, with some evidence indicating that mild traumatic brain injury (TBI) may not impact the associations between subjective and objective cognition. However, few studies have examined these relationships in both mild and moderate-to-severe TBI, in older Veterans, and within specific cognitive domains. Therefore, we assessed the moderating effect of TBI severity on subjective and objective cognition across multiple cognitive domains.
Participants and Methods:This study included 246 predominately male Vietnam-Era Veterans (age M=69.61, SD=4.18, Range = 60.87 – 85.16) who completed neuropsychological testing and symptom questionnaires as part of the Department of Defense-Alzheimer’s Disease Neuroimaging Initiative (DoD-ADNI). Participants were classified as having history of no TBI (n=81), mild TBI (n=80), or moderate-tosevere TBI (n=85). Neuropsychological composite scores in the domains of memory, attention/executive functioning, and language were included as the outcome variables. The Everyday Cognition (ECog) measure was used to capture subjective cognition and, specifically, the ECog domain scores of memory, divided attention, and language were chosen as independent variables to mirror the objective cognitive domains. General linear models, adjusting for age, education, apolipoprotein E ε4 carrier status, pulse pressure, depressive symptom severity, and PTSD symptom severity, tested whether TBI severity moderated the associations of domain-specific subjective and objective cognition.
Results:Across the sample, subjective memory was associated with objective memory (β=-.205, 95% CI [-.332, -.078], p=.002) and subjective language was associated with objective language (β=-.267, 95% CI [-.399, -.134], p<.001). However, the main effect of subjective divided attention was not associated with objective attention/executive functioning (p=.124). The main effect of TBI severity was not associated with any of the objective cognitive domain scores after adjusting for the other variables in the model. The TBI severity x subjective cognition interaction was significant for attention/executive functioning [F(2,234)=5.18, p=.006]. Specifically, relative to Veterans without a TBI, participants with mild TBI (β=-.311, 95% CI [-.620, -.002], p=.048) and moderate-to-severe TBI (β=-.499, 95% CI [-.806, -.193], p=.002) showed stronger negative associations between subjective divided attention and objective attention/executive functioning. TBI severity did not moderate the associations between subjective and objective cognition for memory or language domains. The pattern of results did not change when the total number of TBIs was included in the models.
Conclusions:In this DoD-ADNI sample, stronger associations between subjective and objective attention were evident among individuals with mild and moderate-to-severe TBI compared to Veterans without a TBI history. Attention/executive functioning measures (Trails A and B) may be particularly sensitive to detecting subtle cognitive difficulties related to TBI and/or comorbid psychiatric symptoms, which may contribute to these attention-specific findings. The strongest associations were among those with moderate-to-severe TBI, potentially because the extent to which their attention difficulties are affecting their daily lives are more apparent despite no significant differences in objective attention performance by TBI group. This study highlights the importance of assessing both subjective and objective cognition in older Veterans and the particular relevance of the attention domain within the context of TBI.