Aging / Alzheimer's
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/30803
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Browsing Aging / Alzheimer's by Author "Johnson, Leigh"
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Item Association Between bilingualism and Amyloid Uptake Among Mexican Americans: An HABS-HD Study(2022) Wiley, Elizabeth; Johnson, Leigh; Hall, James; Petersen, Melissa; O'Bryant, SidBackground: Bilingualism is thought to provide protective benefits in regions of the brain associated with the onset of Alzheimer's Disease (AD). While there has been extensive research on bilingualism's effect on grey matter volume, there is no study to date that has examined the relationship between bilingualism and amyloid burden within brain regions characteristically impacted by AD. This study aims to fill this gap by comparing amyloid deposition in Mexican Americans who are either monolingual or bilingual. Methods: Data were analyzed on n=34 Hispanic, Mexican Americans (n=16 bilingual; n=18 monolingual) participants enrolled in a study of health disparities with available Amyloid PET scans. PET Amyloid scans were conducted using florbetaben (18F) on a Siemens Biograph Vision 450 whole-body PET/CT scanner. PET Amyloid SUVR levels were generated from the following Regions of Interest (ROIs): Frontal, Anterior Posterior Cingulate, Lateral Parietal, Lateral Temporal, and Global, with global SUVR>1.08 determined as the cut-off for Amyloid positivity. Independent t-test and chi-square tests were conducted to examine group differences in language status across demographic variables. One-way ANOVAs were conducted to examine groups differences in APOE e4 carrier status as well as in language capabilities (monolingual, bilingual) and PET amyloid SUVR. Follow-up analyses examining language capabilities were split by APOE e4 carrier status (carrier, non-carrier). Results: In comparison to APOE e4 non-carriers, APOE e4 carriers experienced significantly increased amyloid burden across all regional areas, including global (p< 0.05). Bilingual APOE e4 non-carriers showed a significantly increased amyloid deposition in the Anterior/Posterior Cingulate cortex in comparison to monolingual APOE e4 non-carriers. Furthermore, among APOE e4 non-carriers, there was a trend towards significance for global amyloid uptake (p=0.059), with bilinguals again showing higher amyloid burden. Among APOE e4 carriers, no significant associations were found between language status (monolingual, bilingual) and amyloid uptake. Discussion: This was the first study to examine the association between bilingualism and amyloid burden within specific cortical regions of the brain. Results contradicted previous work observing the role of the posterior/anterior cingulate in bilingualism. The trend towards significance in global amyloid uptake for APOE e4 non-carriers favored increased burden in bilinguals, a result opposite of what was expected. Bilingualism is complex and multifactorial and further work is greatly needed to understand the link it has with amyloid burden particularly by disease state.Item Association between inflammation, white matter hyperintensities, and executive function: the role of ethnicity.(2022) Brown, Frank; Vintimilla, Raul; Hall, James; Johnson, Leigh; O'Bryant, SidAssociation between inflammation, white matter hyperintensities, and executive function: the role of ethnicity. Frank Brown1, Raul Vintimilla2, James Hall2, Leigh Johnson2, Sid O'Bryant2, for the HABS-HD Study Team. 1University of North Texas 2University of North Texas Health Science Center, Institute for Translational Research Background: Systemic inflammation and cardiovascular risk factors (CVRF) impact neurological health and executive function. Neutrophils produce inflammatory mediators and lymphocytes regulate the inflammatory response. Neutrophil to lymphocyte ratio (NLR) has been used as a marker of systemic inflammation, and as a predictor of cardiovascular health. CVRF are correlated with white matter hyperintensity volume (WMH), an MRI indicator of cerebrovascular health. This study seeks to compare if there is a difference in the association between inflammation (NLR), WMH, and executive function among Mexican Americans and non-Hispanic Whites. Method: We analyzed data from 1083 (505 Mexican Americans and 578 non -Hispanic Whites) cognitively normal participants from the Health and Aging Brain Study (HABS-HD). All participants signed a written consent, and underwent a 3T MRI (Siemens Skyra), clinical labs, clinical evaluation, and cognitive testing. Differential blood cell counts were used to obtain NLR. WMH volume was measured from FLAIR using the Statistical Parametric Mapping (SPM) Lesion Segmentation Tool. Linear regression was used to predict the effect of NLR and Log transformed WMH adjusted for intracranial volume (derived from Freesurferv6.0 analysis of T1 MPRAGE) on Trails B z-score (executive function), and to evaluate if NLR can predict WMH volume. Analysis was split by ethnicity. Age, sex, and education were entered as covariates in the models. Results: Sixty-four percent of the total sample were female. Means for the whole sample were: age 66.02, education years 12.98, Trails B 0.19, WMH volume -0.035, and NLR 2.16. When compared to non-Hispanic Whites, Mexican Americans were significantly younger, less educated, had lower Trails B score, NLR values and WMH volume. NLR predicted Trails B scores (B = -0.14, t =-0.12, p = 0.004) only in Mexican American, while WMH predicted Trails B scores in Mexican American (B = -0.16, t = -3.02, p = 0.003), and Non-Hispanic Whites (B = -0.14, t = -4.33, p < 0.0001). Results remained significant after adjusting for age, sex, education. NLR predicted WMH volume (B = 0.13, t = 3.38, p = 0.001) only in Mexican American. Conclusion: Our findings suggest an association between NLR, WMH and executive function in Mexican Americans. NLR and WMH volume predicted Trails B scores in Mexican Americans. WMH predicted Trails B scores, but there was no association between NLR and executive function in non-Hispanic Whites. These findings demonstrate the importance of race consideration when assessing the relationship between inflammation, CVRF, WMH, and executive function.Item Effects of Diabetes and White Matter Hyperintensities on Cognition in Mexican Americans Based on APOE e4 Carrier Status: An HABS-HD Study(2022) Mai, Kevin; Petersen, Melissa; Hall, James; Johnson, Leigh; O'Bryant, SidBackground: The U.S. Hispanic population is projected to grow tremendously and face considerable increases in age-related conditions such as Alzheimer's Disease (AD). This same population also experiences a higher frequency of cerebrovascular conditions and diabetic risk factors, both of which have independently been associated with cognitive decline. Previous research demonstrates the impact of Diabetes Mellitus (DM) and white matter hyperintensities (WMHs) on cognitive functioning within the Hispanic population; however, to date, no study has looked into the effects of genetic factors such as APOE-e4 carrier status on the link between these medical conditions and cognition. Methods: Data were analyzed on Mexican American participants from a study of health disparities stratified by DM status (Yes/No) and WMH burden (Low/High): n = 696 APOE e4 non-carriers (n= 206 No DM/Low WMH, n= 73 Yes DM/Low WMH, n= 153 No DM/High WMH, n= 128 Yes DM/High WMH) and n = 157 APOE e4 carriers (n= 48 No DM/Low WMH, n= 17 Yes DM/Low WMH, n= 35 No DM/High WMH, n= 26 Yes DM/High WMH). All participants underwent cognitive testing and a medical exam. Neuropsychological test battery included Trail Making Test Part A and B, WMS-III Digit Span, Mini Mental Status Examination, Spanish and English Verbal Learning Test (Immediate and Delayed Recall), and Digit Symbol Substitution. Diagnosis of DM was categorized as "Yes/No" through past medical history and HbA1c blood work > 6.5. WMH status was based on a median value of 0.816 to separate "Low/High" burden. Genetic testing was completed for APOE e4 to determine carrier status. ANOVAs were conducted stratified by APOEe4 carrier status with medical condition group (Yes/No DM and Low/High WMH) entered as the predictor variable and cognitive test scores as the outcome variable. Tukey post-hoc tests were performed. Results: For APOE e4 non-carriers, participants in the Yes DM/Low WMH, No DM/High WMH, and Yes DM/High WMH groups performed worse than the No DM/Low WMH group on measures of attention, executive functioning, and processing speed. Those in the No DM/High WMH and Yes DM/High WMH groups also performed worse than the No DM/Low WMH group on measures of learning and memory. Among APOE e4 carriers, participants in the Yes DM/High WMH group performed worse than the Low DM/Low WMH group on measures of executive functioning, processing speed, immediate and delayed memory. Also, those in the Yes DM/High WMH group performed worse than the Yes DM/ Low WMH group on measures of global cognition, processing speed and delayed memory. Those in the No DM/ High WMH group performed worse than the No DM/Low WMH group in both immediate and delayed memory. Discussion: In APOE e4 carriers and non-carriers, DM and WMH burden were differentially associated with decreased test performance across multiple cognitive domains. This study tests the combined effect of DM and WMH on cognition in the context of APOE carrier status for Mexican Americans with findings that support the presence of specific associations thereby further highlighting the necessity to explore health disparities.Item Subjective memory complaints and cardiovascular risk factors: a cross-sectional study of the HABS-HD cohort(2022) Mathew, Ezek; Vintimilla, Raul; Hall, James; Johnson, Leigh; O'Bryant, SidBackground: Subjective memory complaints (SMC) are considered as subjects' interpretation of their cognitive aspects, such as memory and perception. Cardiovascular risk factors such as hypertension, diabetes, dyslipidemia, and obesity may contribute to cognitive decline and their relationship with dementia has been documented extensively. However, there is a lack of literature on the relationship between CVRFs and SMC. Depression has been linked to cardiovascular disease and it is strongly associated with SMC, so it is important to consider the contribution of CVRFs and depression as potentially modifiable factors of SMC. Despite the importance of SMC as a risk factor for cognitive decline, and the higher burden of CVRFs, cognitive decline and dementia among minorities like Mexican Americans (MA), not much attention has been paid to the study of SMC in this population. This study examined the factors associated with SMC in community-dwelling older MA and non - Hispanic Whites (NHW), particularly CVRFs and depression. We hypothesized that CVRFs will be associated with SMC, and that the association will be independent of depression. Methods: We studied 1,376 cognitively normal participants (673 MA and 673 NHW) from the Health and Aging Brain Study (HABS - HD). Baseline characteristics were analyzed using t and chi square tests. The presence of SMC was ascertained by the Subjective Memory Complaints Questionnaire (SCMQ). A logistic regression was conducted to examine the relationship of subjective memory complaints with CVRFs and depression. Age, gender, and education were entered as covariates in the model. Results: MA with SMC had a higher prevalence of dyslipidemia (p=0.008), and depression (p< 0.0001) than those without SMC. Fifty nine percent of the NHW sample were female. NHW with SMC were less educated than those without SMC (mean education years 15.26 vs 15.83), and have a higher prevalence of diabetes (p=0.04) and depression (p< 0.0001). When comparing baseline characteristics of MA (323) and NHW (269) with SMC, we found that MA were younger (mean age 63.74 vs 68.85) and less educated (mean education years 9.38 vs 15.26). MA with SMC had a higher prevalence of diabetes (p< 0.0001) and obesity (p=0.0001) when compared with NHW with SMC. Depression was strongly associated with SMC in MA (OR 3.46; 95% CI = 2.45 - 4.89) and NHW (OR 2.22; 95% CI = 1.59 - 3.10). Dyslipidemia was also associated with SMC in MA (OR 1.73; 95% CI = 1.25 - 2.40). NHW with less education had an increased likelihood of exhibiting SMC. Conclusions: Our findings suggest that the association of CVRF and SMC differs among MA and NHW. Depression was strongly associated with SMC in both groups. In MA, dyslipidemia was also associated with SMC in MA, while education was a significant factor only in NHW. The complex relationship between memory complains, vascular risk factors, and depression requires longitudinal studies for further clarification. Understanding SMC and its racial differences may allow early interventions to prevent cognitive decline.Item Visual Function and Cognitive Dysfunction in Older Adults(2022) Rashik, Mohammad Imran; Mozdbar, Sima; Aryal, Subhash; Johnson, Leigh; O'Bryant, SidBackground: Studies have shown a correlation between visual impairment and increased risk of Alzheimer's disease (AD). Therefore, it is important to understand the relationship between visual function and cognitive dysfunction in order to improve care and health-related quality of life. This study assesses the relationship between self-reported visual function and cognitive dysfunction through the use of two questionnaires, the Mini-Mental Status Exam (MMSE) and the 25 item National Eye Institute Vision Function Questionnaire (NEI VFQ-25). Methods: 131 participants from the Alzheimer's Disease in Primary Care (ADPC) study were recruited to complete the NEI VFQ-25. This questionnaire takes into account multiple domains of health and measures the impact of ocular dysfunction on each of the domains. Before completing the questionnaire, as part of the ADPC study, the subjects underwent neuroimaging and a battery of neuropsychological testing, including the MMSE. Based on clinical dementia rating scale (CDR), MMSE scores and additional cognitive testing, participants were classified into three groups of cognitive impairment. These were: normal control with no cognitive impairment (CDR sum of box score equaling 0), mild cognitive impairment (CDR sum of box score between 0.5 to 2) and Alzheimer's dementia (CDR sum of box score over 2.5). To examine the relationship between cognition and self-reported visual function, we performed a Kruskal Wallis test to assess vision specific role difficulties in the three diagnostic categories. Results: The Kruskal Wallis test revealed a significant difference in role difficulties related to vision among the three diagnostic groups (p = 0.04). This means that as the MMSE score decreased due to cognitive impairments, participants reported greater difficulties in their activities of daily living and completion of tasks due to deteriorating eyesight. Conclusions: An important component during the ophthalmic and neuropsychological evaluation of a patient is the consideration of visual function as it relates to quality of life. The need for the NEI-VFQ questionnaire arises because vision tests cannot comprehensively represent the emotional well-being or social function of a patient, formally known as the health-related quality of life. Identifying and addressing reduced visual function could play a role in improving the health-related quality of life for patients who are at an increased risk of cognitive dysfunction.