Rosselli, Mónica

Abstract Background Research on gender and ethnic differences in white matter tracts yields mixed results. Although men show larger global corpus callosum (CC) in absolute values, women have demonstrated larger splenium and isthmus. Additionally, men have shown greater white matter and fractional anisotropy (FA) in multiple regions than women. This study investigates sex and ethnic differences in the corpus callosum and transcallosal white matter tissue microstructure of older individuals with normal cognition and memory disorders. Method 191 participants (Female n = 120; Hispanics n = 115; Non‐Hispanics n = 76; Age mean = 71.07; SD = 7.75) were included in the sample from the 1Florida ADRC with cognitively normal ( n = 75), MCI ( n = 88), and dementia ( n = 28) diagnoses. Corpus callosum volumes were collected using a Siemens Skyra 3T MRI scanner and were divided into anterior, mid‐anterior, central, mid‐posterior, and posterior regions. Also, MRI‐based free water diffusion tensor imaging (FW‐DTI) measured FW‐corrected FA (fwcFA) to assess and compare the integrity of transcallosal tract templates (TCATT) across motor, temporal, parietal, and occipital regions across males and females and ethnic groups. Result Univariate ANCOVAs controlling for age and clinical diagnosis were performed; females had larger normalized CC volumes in the posterior, F (1, 184) = 8.92, p = .003, η p 2 = .046, mid‐anterior, F (1,184)= 5.68, p = .018, η p 2 = .030, and anterior, F (1,184)= 14.54, p < .001, η p 2 = .073, regions, which all survived FDR corrections, with no ethnic differences observed. For transcallosal tracts, females had higher fwcFA in the inferior temporal gyrus, η p 2 Hispanics had higher fwcFA in the premotor cortex, η p 2 η p 2 Conclusion Sex and ethnicity influence white matter changes during aging independently of age and cognitive diagnosis. However, the effect explained by these demographic variables was very small, suggesting the influence of additional factors.

AbstractThe Alzheimer's Association hosted the second Latinos & Alzheimer's Symposium in May 2021. Due to the COVID‐19 pandemic, the meeting was held online over 2 days, with virtual presentations, discussions, mentoring sessions, and posters. The Latino population in the United States is projected to have the steepest increase in Alzheimer's disease (AD) in the next 40 years, compared to other ethnic groups. Latinos have increased risk for AD and other dementias, limited access to quality care, and are severely underrepresented in AD and dementia research and clinical trials. The symposium highlighted developments in AD research with Latino populations, including advances in AD biomarkers, and novel cognitive assessments for Spanish‐speaking populations, as well as the need to effectively recruit and retain Latinos in clinical research, and how best to deliver health‐care services and to aid caregivers of Latinos living with AD.

Background: Plasma NfL (pNfL) levels are elevated in many neurological disorders. However, the utility of pNfL in a clinical setting has not been established. Objective: In a cohort of diverse older participants, we examined: 1) the association of pNfL to age, sex, Hispanic ethnicity, diagnosis, and structural and amyloid imaging biomarkers; and 2) its association to baseline and longitudinal cognitive and functional performance. Methods: 309 subjects were classified at baseline as cognitively normal (CN) or with cognitive impairment. Most subjects had structural MRI and amyloid PET scans. The most frequent etiological diagnosis was Alzheimer’s disease (AD), but other neurological and neuropsychiatric disorders were also represented. We assessed the relationship of pNfL to cognitive and functional status, primary etiology, imaging biomarkers, and to cognitive and functional decline. Results: pNfL increased with age, degree of hippocampal atrophy, and amyloid load, and was higher in females among CN subjects, but was not associated with Hispanic ethnicity. Compared to CN subjects, pNfL was elevated among those with AD or FTLD, but not those with neuropsychiatric or other disorders. Hippocampal atrophy, amyloid positivity and higher pNfL levels each added unique variance in predicting greater functional impairment on the CDR-SB at baseline. Higher baseline pNfL levels also predicted greater cognitive and functional decline after accounting for hippocampal atrophy and memory scores at baseline. Conclusion: pNfL may have a complementary and supportive role to brain imaging and cognitive testing in a memory disorder evaluation, although its diagnostic sensitivity and specificity as a stand-alone measure is modest. In the absence of expensive neuroimaging tests, pNfL could be used for differentiating neurodegenerative disease from neuropsychiatric disorders.