Apolipoprotein E and Alzheimer's disease pathology in African American older adults

The apolipoprotein-E4 (APOE*4) and apolipoprotein-E2 (APOE*2) alleles are more common in African American versus non-Hispanic white populations, but relationships of both alleles with Alzheimer's disease (AD) pathology among African American individuals are unclear. We measured APOE allele and β-amyloid (Aβ) and tau using blood samples and positron emission tomography (PET) images, respectively. Individual regression models tested associations of each APOE allele with Aβ or tau PET overall, stratified by racialized group, and with a racialized group interaction. We included 358 older adults (42% African American) with Aβ PET, 134 (29% African American) of whom had tau PET. APOE*4 was associated with higher Aβ in non-Hispanic white (P < 0.0001), but not African American (P = 0.64) participants; racialized group modified the association between APOE*4 and Aβ (P < 0.0001). There were no other racialized group differences. These results suggest that the association of APOE*4 and Aβ differs between African American and non-Hispanic white populations. Other drivers of AD pathology in African American populations should be identified as potential therapeutic targets.

Unhealthy white matter connectivity, cognition, and racialization in older adults

INTRODUCTION

White matter hyperintensities (WMH) may promote clinical Alzheimer's disease (AD) disparities between Black American (BA) and non-Hispanic White (nHW) populations. Using a novel measurement, unhealthy white matter connectivity (UWMC), we interrogated racialized group differences in associations between WMH in AD pathology-affected regions and cognition.

METHODS

UWMC is the proportion of white matter fibers that pass through WMH for every pair of brain regions. Individual regression models tested associations of UWMC in beta-amyloid (Aβ) or tau pathology-affected regions with cognition overall, stratified by racialized group, and with a racialized group interaction.

RESULTS

In 201 older adults ranging from cognitively unimpaired to AD, BA participants exhibited greater UWMC and worse cognition than nHW participants. UWMC was negatively associated with cognition in 17 and 5 Aβ- and tau-affected regions, respectively. Racialization did not modify these relationships.

DISCUSSION

Differential UWMC burden, not differential UWMC-and-cognition associations, may drive clinical AD disparities between racialized groups.

HIGHLIGHTS

Unhealthy white matter connectivity (UWMC) in Alzheimer's disease (AD) pathology-affected brain regions is associated with cognition. Relationships between UWMC and cognition are similar between Black American (BA) and non-Hispanic White (nHW) individuals. More UWMC may partially drive higher clinical AD burden in BA versus nHW populations. UWMC risk factors, particularly social and environmental, should be identified.

MEG Oscillatory Slowing in Cognitive Impairment is Associated with the Presence of Subjective Cognitive Decline

The mechanisms behind Alzheimer's disease are not yet fully described, and changes in the electrophysiology of patients across the continuum of the disease could help to understand them. In this work, we study the power spectral distribution of a set of 129 individuals from the Connectomics of Brian Aging and Dementia project.From this sample, we acquired task-free data, with eyes closed, and estimated the power spectral distribution in source space. We compared the spectral profiles of three groups of individuals: 70 healthy controls, 27 patients with amnestic MCI, and 32 individuals showing cognitive impairment without subjective complaints (IWOC).The results showed a slowing of the brain activity in the aMCI patients, when compared to both the healthy controls and the IWOC individuals. These differences appeared both as a decrease in power for high frequency oscillations and an increase in power in alpha oscillations. The slowing of the spectrum was significant mainly in parietal and medial frontal areas.We were able to validate the slowing of the brain activity in individuals with aMCI, appearing in our sample in areas related to the default mode network. However, this pattern did not appear in the IWOC individuals, suggesting that their condition is not part of the AD continuum. This work raises interesting questions about this group of individuals, and the underlying brain mechanisms behind their cognitive impairment.

Tract Specific White Matter Lesion Load Affects White Matter Microstructure and Their Relationships With Functional Connectivity and Cognitive Decline

White matter hyperintensities (WMHs) are associated with cognitive decline. Assessing the effect of WMH on WM microstructural changes and its relationships with structural and functional connectivity to multiple cognitive domains are helpful to better understand the pathophysiological processes of cognitive impairment. 65 participants (49 normal and 16 MCI subjects, age: 67.4 ± 8.3 years, 44 females) were studied at 3T. The WMHs and fifty fiber tracts were automatically segmented from the T1/T2-weighted images and diffusion-weighted images, respectively. Tract-profiles of WMH were compared with those of apparent fiber density (AFD). The relationship between AFD and tract connectivity (TC) was assessed. Functional connectivity (FC) between tract ends obtained from resting-state functional MRI was examined in relation to TC. Tract-specific relationships of WMH, TC and FC with a multi-domain neuropsychological test battery and Montreal Cognitive Assessment (MoCA) were also separately assessed by lasso linear regression. Indirect pathways of TC and FC between WMH and multiple cognitive measures were tested using the mediation analysis. Higher WMH loads in WM tracts were locally matched with the reduced AFD, which was related to decrease in TC. However, no direct relationship was found between TC and FC. Tract-specific changes on WMH, TC and FC for each cognitive performance may explain that macro- and microstructural and functional changes are associated differently with each cognitive domain in a fiber specific manner. In these identified tracts, the differences between normal and MCI for WMH and TC were increased, and the relationships of WMH, TC and FC with cognitive outcomes were more significant, compared to the results from all tracts. Indirect pathways of two-step (TC-FC) between WMH and all cognitive domains were significant (p < 0.0083 with Bonferroni correction), while the separated indirect pathways through TC and through FC were different depending on cognitive domain. Deterioration in specific cognitive domains may be affected by alterations in a set of different tracts that are differently associated with macrostructural, microstructural, and function changes. Thus, assessments of WMH and its associated changes on specific tracts help for better understanding of the interrelationships of multiple changes in cognitive impairment.

Sex Differences in Magnetoencephalography-Identified Functional Connectivity in the Human Connectome Project Connectomics of Brain Aging and Dementia Cohort

Introduction: The human brain shows modest traits of sexual dimorphism, with the female brain, on average, 10% smaller than the male brain. These differences do not imply a lowered cognitive performance, but suggest a more optimal brain organization in women. Here we evaluate the patterns of functional connectivity (FC) in women and men from the Connectomics of Brain Aging and Dementia sample. Methods: We used phase locking values to calculate FC from the magnetoencephalography time series in a sample of 138 old adults (87 females and 51 males). We compared the FC patterns between sexes, with the intention of detecting regions with different levels of connectivity. Results: We found a frontal cluster, involving anterior cingulate and the medial frontal lobe, where women showed higher FC values than men. Involved connections included the following: (1) medial parietal areas, such as posterior cingulate cortices and precunei; (2) right insula; and (3) medium cingulate and paracingulate cortices. Moreover, these differences persisted when considering only cognitively intact individuals, but not when considering only cognitively impaired individuals. Discussion: Increased anteroposterior FC has been identified as a biomarker for increased risk of developing cognitive impairment or dementia. In our study, cognitively intact women showed higher levels of FC than their male counterparts. This result suggests that neurodegenerative processes could be taking place in these women, but the changes are undetected by current diagnosis tools. FC, as measured here, might be valuable for early identification of this neurodegeneration.

Connectomics in Brain Aging and Dementia - The Background and Design of a Study of a Connectome Related to Human Disease

The natural history of Alzheimer’s Disease (AD) includes significant alterations in the human connectome, and this disconnection results in the dementia of AD. The organizing principle of our research project is the idea that the expression of cognitive dysfunction in the elderly is the result of two independent processes — the neuropathology associated with AD, and second the neuropathological changes of cerebrovascular disease. Synaptic loss, senile plaques, and neurofibrillary tangles are the functional and diagnostic hallmarks of AD, but it is the structural changes as a consequence of vascular disease that reduce brain reserve and compensation, resulting in an earlier expression of the clinical dementia syndrome. This work is being completed under the auspices of the Human Connectome Project (HCP). We have achieved an equal representation of Black individuals (vs. White individuals) and enrolled 60% Women. Each of the participants contributes demographic, behavioral and laboratory data. We acquire data relative to vascular risk, and the participants also undergo in vivo amyloid imaging, and magnetoencephalography (MEG). All of the data are publicly available under the HCP guidelines using the Connectome Coordinating Facility and the NIMH Data Archive. Locally, we use these data to address specific questions related to structure, function, AD, aging and vascular disease in multi-modality studies leveraging the differential advantages of magnetic resonance imaging (MRI), functional magnetic resonance imaging (fMRI), MEG, and in vivo beta amyloid imaging.

Impact of a personal emergency response system on hospital utilization by community-residing elders

The purpose of this study was to determine whether use of a 24-hour personal emergency response system (PERS) might be associated with selected hospital utilization rates among community-residing users. Utilization rates of 106 patients were reviewed for 1 year before and 1 year after enrollment in the PERS. Self-paired analyses were conducted on number of visits to an emergency department (ED), number of hospital inpatient admissions, and number of inpatient days. During the 1-year follow-up period, those subscribers using the PERS had a statistically significant decrease in per person hospital admissions and inpatient days. No significant differences occurred in ED visits. When indicated, a PERS may be an appropriate environmental prescription.

Scholarly productivity: a regional study of physical therapy faculty in schools of allied health

A study of the scholarly activities of physical therapy faculty members in selected schools of allied health was conducted through a mailed questionnaire survey. The analysis of the data provided by the respondents (N = 127; 97.6%) revealed the following: 1) the respondents' primary scholarly activity was authorship of referred journal articles; 2) a majority of the respondents presented a paper at a professional meeting during the past three years; 3) only a small percentage of the respondents had directed extramurally funded projects; 4) the majority of the respondents indicated that their own academic preparation was the primary factor that encouraged their scholarly pursuits and that heavy teaching and administrative responsibilities were the primary discouraging factors; and 5) the respondents indicated that faculty scholarly activities are, and will continue to be, important considerations in academic promotion decisions. Comparison of the data provided by these respondents with data from the 1983 American Physical Therapy Association physical therapy faculty survey suggests modest gains in scholarly productivity. The implications of these findings are that faculty development programs are warranted and physical therapy administrators and faculty should join forces in finding more effective ways to involve faculty in research activities.

The scholarly productivity of occupational therapy faculty members: results of a regional study

A study of the scholarly activities of 66 occupational therapy faculty members at selected academic health centers was conducted through a mailed survey. An analysis of the responses showed that (a) the respondents' primary scholarly activities were reporting research findings in refereed journal articles and presenting papers at professional meetings and (b) only a small percentage of the respondents had directed extramurally funded projects. In addition, the level of scholarly productivity of the occupational therapists was significantly lower than that of their allied health colleagues. The majority of the respondents indicated that their own academic preparation was the primary factor that encouraged their scholarly pursuits and that heavy teaching responsibility was the primary discouraging factor. The respondents indicated also that faculty scholarly activities are, and will continue to be, important considerations in academic promotion decisions.

A study of the scholarly activities of allied health faculty in southern academic health science centers

A study of the scholarly activities of 942 allied health faculty members in southern academic health centers was conducted through a mailed survey. The analysis of the responses from respondents (N = 780; 82.8%) found that (1) the scholarly activities of the respondents were primarily refereed journal articles through which they reported research findings; to a much lesser extent, the respondents authored books, chapters in books, monographs, and other publications; (2) less than a majority (46%) of the respondents presented a paper at a professional meeting over the past three years; (3) only a small percentage of respondents (29%) had directed extramurally funded projects; (4) the majority of the respondents (56%) indicated that their own academic preparation was the primary factor that encouraged their scholarly pursuits, and heavy teaching responsibility was the primary discouraging factor (62%); and (5) the respondents believed that faculty scholarly activities are, and will continue to be, important considerations in academic promotion decisions.

The training of multicompetent allied health professionals using a combined-fields method

With the advent of DRGs, quality and cost have become the chief considerations of care providers and institutional managers; as a result, persons who can perform competently in crossover fields may be more employable and valuable than their single-credentialed counterparts. In academic health centers with more than one health-related school, opportunities exist to combine degree programs that result in educating multicompetent health care providers (MCHCP). In lieu of thinking about interdisciplinary education in the traditional sense, the training of MCHCPs can be achieved by simply combining one or more aspects of their respective curricula. Three methods--intra-, across-, and extra-field combinations--of melding two historically separate fields are described. An example of an across-field combination--the Baylor College of Medicine Physician Assistant/Perfusion Technology Program--is given.

Training allied health professionals to deliver breast-feeding services to women in the pre- and postnatal periods

Results of a recently completed project at Baylor College of Medicine suggest that schools of allied health could incorporate a breast-feeding education program into existing allied health curricula. The need for such programs is the medical indication for the increased use of human milk for all segments of the population, especially for infants in the lower socioeconomic strata because of their higher risk to nutritionally related problems and infectious diseases. Paradoxically, increases in breast-feeding are occurring almost exclusively in the middle and upper classes. The benefits of breast-feeding to both mother and child are great: lower incidence of certain disease processes, enhanced psychological adjustment, and increased economic savings. Training allied health professionals in breast-feeding could help alleviate the problem of higher risks of nutritional deficiencies and infectious diseases among groups that do not traditionally breast-feed their infants.

Dental technology program administrators' attitudes toward credentialing health manpower

The purpose of this study was to identify the attitudes of administrators of dental technology programs toward health manpower credentialing. A survey instrument was developed by allied health professionals knowledgeable in the credentialing process. The instrument contained 32 items that were categorized into three subscales and sought information about academic program accreditation, certification, and the licensure of dental technicians. The survey was sent to the directors of the 57 dental technology programs accredited by the American Dental Association, Usable returns totaled 49, or 86 percent. The data indicated that dental technology program administrators support the concept and practice of health manpower credentialing. The data also indicated that these administrators felt that academic program accreditation was of value in meeting demands for quality assurance in dental technology, and that certification of technicians, while beneficial, had been of little value in terms of rewards (recognition and economic gains) for the credential holder. In addition, licensure of dental technicians was found to be desirable.

Preparing faculty for the allied health professions: a follow-up study of a program's graduates

Since 1972, Baylor College of Medicine, the University of Houston and Texas A&M University have jointly offered a graduate Program in Allied Health Teacher Education and Administration. The purpose of the program is to prepare faculty and administrative leaders for allied health education programs. As of December 1978, a total of 94 allied health professionals had completed master's or doctoral degrees and most of them are currently pursuing academic careers. This article describes the results of a follow-up study of these graduates to determine their current activities, locations and job satisfaction and to make decisions regarding the success of the program in raching its goals.