Abstract Background Long‐term forgetting (LTF) over days or weeks may be a sensitive early marker of Alzheimer’s disease (AD), useful for preclinical AD trials. We examined associations between LTF and markers of brain pathology in individuals from the world’s largest kindred with autosomal dominant AD due to the Presenilin‐1 (PSEN1) E280A mutation. Methods A total of 14 cognitively unimpaired PSEN1 mutation carriers (mean age: 35.9 years) and 16 matched non‐carriers (mean age: 32.8 years) from the Colombia‐Boston Biomarker Study of autosomal dominant AD were included. Participants underwent amyloid (11‐C Pittsburgh compound B) and tau (Flortaucipir) PET imaging, and memory tasks (NEUROPSI word list, stories and semi‐complex figure). We examined performance on learning and delayed recall after a 20‐min, 1‐day and 7‐day interval. LTF was calculated for the three tasks as the proportion of material retained at 20 min that was recalled 7 days later. Mann‐Whitney tests were conducted to compare memory performance and LTF between PSEN1 mutation carriers and non‐carriers. Spearman’s correlations were used to examine the association between LTF and brain pathology markers of amyloid burden and regional tau (entorhinal and inferior temporal cortices). Fisher’s exact tests were used to compare correlation coefficients between groups. Results Learning did not differ between carriers and non‐carriers. Compared to non‐carriers, carriers had lower 20‐min recall in all three tasks (p<0.05), and lower 1‐day and 7‐day recall of word list and stories. There were no group differences in word list, stories or figure LTF. Further, no group differences were observed in the association of amyloid burden and LTF on any of the tasks. Lower word list LTF was associated with greater entorhinal burden among carriers, and the strength of this association was significantly different between carriers and non‐carriers (p = 0.046; carriers: r = 0.73, p = 0.003; non‐carriers: r = 0.43, p = 0.094). Conclusions Our preliminary findings show that, while rates of LTF over 7 days did not differ between PSEN1 carriers and non‐carriers, carriers had lower verbal memory recall over 1 and 7 days. Further, LTF was associated with early tau accumulation, suggesting that longer recall intervals may be more sensitive to detect subtle memory changes in cognitively unimpaired individuals at risk for AD.
Abstract Background Latinos are the fastest growing subpopulation of older adults in the U.S. and have a higher risk for dementia than non‐Latino Whites. Depressive symptoms are prevalent among US Latinos. However, these symptoms often go undiagnosed and are undertreated. Depressive symptoms may be early manifestations of Alzheimer’s Disease (AD) before the onset of mild cognitive impairment and dementia. It’s unclear whether depressive symptoms in the presence of incipient neurodegeneration are associated with cognitive function in older Latino adults. Here, we examined the associations among depressive symptoms, cognition and hippocampal volume in older Latinos. Method A total of 65 Spanish‐speaking Latinos enrolled in the Boston Latino Aging Study (BLAST) and the Harvard Aging Brain Study (HABS) were included. Depressive symptoms were assessed with the 30‐item‐Geriatric Depression Scale (GDS) and cognition with the Preclinical Alzheimer’s Cognitive Composite (PACC5), which includes the Mini‐Mental State Examination (MMSE), Digit Symbol Coding, Free and Cued Selective Reminding Test, Category Fluency (animals) and Logical Memory Delayed Recall (NEUROPSI Stories for BLAST participants). A subset of 34 participants also underwent a structural brain MRI on a 3T scanner. Spearman correlations were used to determine cross‐sectional associations among depressive symptoms, hippocampal volume, and cognition. Models were adjusted for age and education. Results Participants had a mean age of 66 +/‐ 7.2 years, a mean education of 12.9 +/‐ 5.1 years, and 74% were female. They had a mean MMSE score of 26.7 +/‐ 2.8, a mean GDS score of 6.1 +/‐ 5.5 and a mean adjusted hippocampal volume of 7836.5 +/ = 630.9 mm 3 . Correlation analyses revealed that higher depressive symptoms were associated with lower years of education (r = ‐0.39, p<0.001), worse performance on cognitive measures (r = ‐0.33, p = 0.009) and smaller hippocampal volume (r = ‐0.61, p = <0.001). Conclusions Preliminary results of this ongoing biomarker study suggest that depressive symptoms in older Latinos are associated with markers of neurodegeneration (i.e., hippocampal volume) and worse cognition. Future work will focus on investigating predictors of long‐term emotional and cognitive functioning in Spanish‐speaking, older Latino populations.
Objective: Neurofilament light chain (NfL), a plasma-based biomarker for neurodegeneration, is a promising marker for early Alzheimer disease (AD) detection in individuals at increased risk. We previously reported that Presenilin1 (PSEN1) E280A carriers have increased levels of plasma NfL relative to non-carrier family members twenty years before the onset of clinical symptoms. Abstract reasoning is one of the first cognitive abilities to deteriorate in AD. Here, we examined whether levels of plasma NfL were associated with non-verbal abstract reasoning performance in non-demented PSEN1-E280A carriers and non-carriers. Participants and Methods: A total of 798 members of the Colombian kindred with the PSEN1 E280A mutation (462 cognitively-unimpaired and 336 non-carriers; mean age= 34.02 (10.53), mean education= 8.23(4.60), 57% females and 43% males) were included in the study. Participants completed the Raven’s Progressive Matrices (RPM), Mini Mental State Examination (MMSE), and underwent blood sampling. Plasma NfL concentrations were measured with a single molecule array (Simoa) method. Mann-Whitney U test and education-adjusted Spearman partial correlation were used to examine group differences and associations between abstract reasoning performance and NfL levels. Results: Non-carriers were older (p <.001) and had higher levels of education than carriers (p =.025). Compared to non-carriers, carriers had higher levels of NfL (p =.014), lower performance on the MMSE (p <.001) and on the RPM (p =.001). In the whole sample, performance on the RPM was significantly associated with age (r= -.144, p <.001), and MMSE score (r =.198, p <.001). In carriers only, performance on the RPM was negatively associated with NfL levels (r =-.121, p =.009). This association was not significant in non-carriers. Conclusions: Our findings support the hypothesis that plasma NfL levels may be indicators of disease progression and early cognitive dysfunction in autosomal dominant AD. Future work with NfL, abstract reasoning and memory with larger samples across the preclinical/prodromal spectrum will allow a more comprehensive examination of these associations.
Abstract Background The prevalence of dementia in populations that are underrepresented in research is projected to increase with population aging. Latino and Black individuals, the largest underrepresented populations in the US, experience a higher dementia burden than non‐Hispanic White individuals, which is not explained by ethnoracial biological factors. Disparities in structural and social determinants of health may contribute to the preponderance of medical conditions known to increase dementia risk, including potentially modifiable factors in Latino and Black communities. To assess the scope of this problem, we measured the frequency of common modifiable dementia risk factors in community‐dwelling, cognitively normal, Latino and Black adults. Method Cognitively normal community‐dwelling Latino and Black adults, ≥45‐years‐old, were enrolled within our longitudinal study of memory and aging at Mayo Clinic in Florida (Jacksonville, FL) and completed a baseline assessment between 3/2022 and 10/2023. Demographics, and self‐reported race/ethnicity and history of dementia risk factors were recorded. Dementia risk factors were objectively sampled through clinical interview (depression: Geriatric Depression Scale ≥5), examination (hypertension: BP >130/80 mmHg; obesity: BMI≥30), and serum analyses (hyperlipidemia: total cholesterol<200mg/dL, HDL>50mg/dL, LDL<100mg/dL, Triglycerides<150mg/dL; diabetes: HbA1C >5.6%, vitamin B12 deficiency: <350 ng/dL). Result 86 participants (43 Latino, 43 Black), 65.8 (8.8) years‐old, female (62.8%), with 16 (2.4) years of education were assessed. Dementia risk factors were frequent in Latino and Black participants, including hypertension (63%, 90%; p = 0.005), hyperlipidemia (93%, 89%; p = 0.702), obesity (33%, 44%; p = 0.370), diabetes (60%, 47%; p = 0.370), vitamin B12 deficiency (21%, 21%; p = 0.989), and depression (5%, 24%; p = 0.781). These risk factors were unrecognized or suboptimally managed in a substantial proportion of Latino and Black participants: hypertension (56%, 73%; p = 0.170), hyperlipidemia (80%, 73%; p = 0.591), diabetes (57%, 47%; p = 0.502), vitamin B12 deficiency (21%, 21%; p = 0.789), and depression (5%, 3%; p>0.99). Conclusion Potentially modifiable dementia risk factors were detected in the majority of community‐dwelling Latino and Black cognitively normal older‐adults and were frequently unrecognized or suboptimally managed. Proactive screening for known dementia risk factors may provide opportunities for targeted interventions to improve brain health and decrease dementia disparities in underrepresented populations.
Abstract Background Methods available for in‐vivo diagnosis of Alzheimer's disease (AD) are expensive and invasive. Neurofilament light chain (NfL), a plasma‐based biomarker for neurodegeneration, is a promising marker for early detection in individuals at increased risk. We previously reported that Presenilin1 ( PSEN1 ) E280A carriers have increased levels of plasma NfL relative to non‐carrier family members twenty years before the onset of clinical symptoms. Here, we examined whether baseline levels of plasma NfL predict self‐reported sleep quality and cognition 10 years later in non‐demented PSEN1 ‐E280A carriers and non‐carriers. Methods A total of 51 PSEN1 ‐E280A carriers (mean age = 30.06, SD = 4.63), including 2 mildly impaired carriers and 49 age‐matched non‐carriers (mean age = 35.55, SD = 6.16) from the Colombia‐Boston (COLBOS) longitudinal biomarker study were included. Participants underwent blood sampling at baseline and completed the Pittsburgh Sleep Quality Index (PSQI), Mini Mental State Exam (MMSE), and memory testing (CERAD Word List) at follow‐up approximately 10 years later. Self‐reported sleep quality was assessed by calculating the PSQI score. Plasma NfL concentrations were measured with a single molecule array (Simoa) method. Linear regressions were used to examine associations among NfL levels, sleep quality, and memory. Results There were no group differences, between carriers and non‐carriers, in baseline NfL levels, memory performance, or total PSQI scores (p>0.05). However, carriers had lower MMSE scores than non‐carriers (carriers M=27.90; non‐carriers M=28.47; p = 0.05). Among the entire sample, baseline NfL levels predicted recall scores on the CERAD word list (p = 0.03) and MMSE performance (p = 0.02). Additionally, associations between NfL levels and age trended toward significance (p = 0.06). Sleep quality (PSQI) was not associated with age, memory performance, or NfL levels. Conclusions Preliminary findings support the hypothesis that plasma NfL levels may predict memory function and overall cognitive status in ADAD. However, our findings suggest that NfL levels may not be associated with self‐reported sleep quality in individuals in prodromal stages of ADAD. Future work using objective sleep metrics and larger samples across the preclinical/prodromal spectrum will allow a more comprehensive examination of these associations.
Abstract Background The disruption of brain functional connections has been linked to cognitive impairment in Alzheimer’s disease. The functional architecture of the brain can be modeled using graph theory, which provides metrics to describe both local and global network properties. Autosomal dominant Alzheimer’s disease (ADAD) provides a unique opportunity to study brain changes in preclinical AD since carriers of ADAD mutations are destined to develop dementia at young age and have a well‐characterized disease trajectory. Here, we applied a graph theory approach to examine the functional network topology in Presenilin‐1 (PSEN1) E280A carriers and non‐carriers. Methods A total of 43 cognitively‐unimpaired individuals (18 PSEN1 carriers, 25 non‐carriers; mean age = 36.6±5.2) from the Colombia‐Boston biomarker study were included. Participants underwent resting‐state fMRI in a 3T scanner, and a comprehensive multi‐domain neuropsychological battery. fMRI data were preprocessed using C‐PAC. Global functional connectivity (FC) was derived from the nodal strength of the Pearson correlation matrix between time‐series of 400 ROIs [Shaeffer‐2016] within 6 different functional networks [Yeo‐2011]. The strength of within‐ (z) and between‐network (h) functional integration was derived from a consensus modularity analysis [Dwyer‐2014]. Differences in cognitive variables were evaluated using Mann‐Whitney tests. Differences in FC were assessed using permutation methods: global FC using FSL‐randomize and integration parameters were based on a consensus analysis applied to random controlled matrices. Both methods were repeated 1000 times, with a p<0.05 significance threshold. Results There were no group differences in cognitive variables. Compared to non‐carriers, carriers exhibited decreased local FC in higher‐order association areas, and increased connectivity in somatosensory areas. There were no group differences in the within‐network integration. Carriers showed decreased between‐network integration, especially in higher‐order association networks, mainly the default mode network (Fig.1). Conclusions Findings support the hypothesis that alterations of functional network topology are evident in preclinical ADAD, primarily in the higher‐order cognitive networks. Early identification of abnormalities within these networks may be useful in understanding how FC changes may lead to subsequent cognitive decline in individuals at increased risk for AD. Future work with larger samples should investigate the relationships between FC changes and the neurobiological factors underlying AD.
This dissertation presents a line of research that explores the association between highincidence psychiatric disorders, specifically Attention-Deficit/Hyperactivity Disorder (ADHD) and depression, and adverse driving outcomes.In addition to examining the magnitude of risk posed by high incidence psychiatric disorders, through evaluation of self-reported as well as criterion-based, objective markers of driving behavior (e.g., number of violations, collisions, at-fault collisions, and collision severity), the role of visual inattention and disinhibition as potential mechanisms of risk is explored.
Abstract Background Mayo Test DRIVE (MTD): Test D evelopment through R apid I teration, V alidation and E xpansion, is a web‐based multi‐device (smartphone, tablet, personal computer) platform optimized for remote self‐administered cognitive assessment that includes a computer‐adaptive word list memory test (Stricker Learning Span; SLS), a measure of processing speed/executive functioning (Symbols Test) and a score combining both the memory and processing speed/executive functioning measures (MTD Composite). We aimed to determine the reliability of MTD measures across follow‐up sessions. Method Individuals participating in this ancillary study who completed at least two and up to four complete MTD sessions were included, resulting in 1,293 participants (mean age = 70.6, SD = 11.6; mean education = 15.6, SD = 2.3; 48.6% male; 96.9% White; 99.1% non‐Hispanic; 97.1% cognitively unimpaired) from parent studies (see Table 1). MTD raw scores were winsorized at 1% and 99% to minimize the impact of outliers. Test‐retest reliability was assessed using single‐rating, absolute‐agreement, and two‐way mixed ICCs and results are described using descriptives from Koo et al. (2016). ICCs for in‐person‐administered traditional neuropsychological measures are also reported alongside MTD for a subset of participants newly enrolled into the MCSA (to ensure participants were test naïve to both MTD and in‐person tests). Result Reliability was good for the MTD Composite raw [total ICC = 0.78; see Table 2 for session‐to‐session ICCs and 95% CIs], and moderate‐to‐good for the primary outcome variables for each subtest [total ICC = 0.74 for both SLS and Symbols]. Weighting by accuracy negatively impacted reliability of Symbols and the Composite; without this weighting, MTD Composite and Symbols variables showed higher reliability (MTD Composite z total ICC = 0.80; Symbols response time total ICC = 0.84; see Table 2). Alternative methods of defining response time on Symbols showed nearly identical reliability values. SLS sum of trials (primary variable) had subtly higher reliability than separate measures of learning (1‐5 correct, max span) or delay. Reliability of remote MTD and in‐person‐administered measures and select comparisons are provided in Table 3. Conclusion MTD showed moderate to good reliability, similar to in‐person‐administered traditional neuropsychological tests. Future work will examine the effect of demographics, device type, and session interference on reliability.
