Exploring the contribution of spatial navigation to cognitive functioning in older adults

Spatial navigation (SN) impairment is present early in Alzheimer's disease (AD). We tested whether SN performance, self-centered (egocentric) and world-centered (allocentric), was distinguishable from performance on established cognitive functions—verbal and nonverbal memory, executive and visuospatial function, attention/working memory, and language function. 108 older adults (53 cognitively normal [CN] and 55 with amnestic mild cognitive impairment [aMCI]) underwent neuropsychological examination and real-space navigation testing. Subset (n = 63) had automated hippocampal volumetry. In a factor analysis, allocentric and egocentric navigation tasks loaded highly onto the same factor with low loadings on other factors comprising other cognitive functions. In linear regression, performance on other cognitive functions was not, or was only marginally, associated with spatial navigation performance in CN or aMCI groups. After adjustment for age, gender, and education, right hippocampal volume explained 26% of the variance in allocentric navigation in aMCI group. In conclusion, spatial navigation, a known cognitive marker of early AD, may be distinguished from other cognitive functions. Therefore, its assessment along with other major cognitive functions may be highly beneficial in terms of obtaining a comprehensive neuropsychological profile

Sex differences in brain atrophy in dementia with Lewy bodies

\ua9 2023 The Authors. Alzheimer\u27s & Dementia published by Wiley Periodicals LLC on behalf of Alzheimer\u27s Association.INTRODUCTION: Sex influences neurodegeneration, but it has been poorly investigated in dementia with Lewy bodies (DLB). We investigated sex differences in brain atrophy in DLB using magnetic resonance imaging (MRI). METHODS: We included 436 patients from the European-DLB consortium and the Mayo Clinic. Sex differences and sex-by-age interactions were assessed through visual atrophy rating scales (n = 327; 73 \ub1 8 years, 62% males) and automated estimations of regional gray matter volume and cortical thickness (n = 165; 69 \ub1 9 years, 72% males). RESULTS: We found a higher likelihood of frontal atrophy and smaller volumes in six cortical regions in males and thinner olfactory cortices in females. There were significant sex-by-age interactions in volume (six regions) and cortical thickness (seven regions) across the entire cortex. DISCUSSION: We demonstrate that males have more widespread cortical atrophy at younger ages, but differences tend to disappear with increasing age, with males and females converging around the age of 75. Highlights: Male DLB patients had higher odds for frontal atrophy on radiological visual rating scales. Male DLB patients displayed a widespread pattern of cortical gray matter alterations on automated methods. Sex differences in gray matter measures in DLB tended to disappear with increasing age

Gray Matter Changes in Parkinson's and Alzheimer's Disease and Relation to Cognition

Purpose of Review We summarize structural (s)MRI findings of gray matter (GM) atrophy related to cognitive impairment in Alzheimer's disease (AD) and Parkinson's disease (PD) in light of new analytical approaches and recent longitudinal studies results. Recent Findings The hippocampus-to-cortex ratio seems to be the best sMRI biomarker to discriminate between various AD subtypes, following the spatial distribution of tau pathology, and predict rate of cognitive decline. PD is clinically far more variable than AD, with heterogeneous underlying brain pathology. Novel multivariate approaches have been used to describe patterns of early subcortical and cortical changes that relate to more malignant courses of PD. New emerging analytical approaches that combine structural MRI data with clinical and other biomarker outcomes hold promise for detecting specific GM changes in the early stages of PD and preclinical AD that may predict mild cognitive impairment and dementia conversion

Sex and gender differences in Alzheimer's disease: current challenges and implications for clinical practice: Position paper of the Dementia and Cognitive Disorders Panel of the European Academy of Neurology

Alzheimer's disease (AD) is characterized by high heterogeneity in disease manifestation, progression and risk factors. High phenotypic variability is currently regarded as one of the largest hurdles in early diagnosis and in the design of clinical trials; there is therefore great interest in identifying factors driving variability that can be used for patient stratification. In addition to genetic and lifestyle factors, the individual's sex and gender are emerging as crucial drivers of phenotypic variability. Evidence exists on sex and gender differences in the rate of cognitive deterioration and brain atrophy, and in the effect of risk factors as well as in the patterns of diagnostic biomarkers. Such evidence might be of high relevance and requires attention in clinical practice and clinical trials. However, sex and gender differences are currently seldom appreciated; importantly, consideration of sex and gender differences is not currently a focus in the design and analysis of clinical trials for AD. The objective of this position paper is (i) to provide an overview of known sex and gender differences that might have implications for clinical practice, (ii) to identify the most important knowledge gaps in the field (with a special regard to clinical trials) and (iii) to provide conclusions for future studies. This scientific statement is endorsed by the European Academy of Neurology

Cognitive and Motor Decline in Dementia with Lewy Bodies and Parkinson's Disease Dementia

Background: There is a need to better understand the rate of cognitive and motor decline of Dementia with Lewy bodies (DLB) and Parkinson's disease Dementia (PDD). Objectives: To compare the rate of cognitive and motor decline in patients with DLB and PDD from the E-DLB Consortium and the Parkinson's Incidence Cohorts Collaboration (PICC) Cohorts. Methods: The annual change in MMSE and MDS-UPDRS part III was estimated using linear mixed regression models in patients with at least one follow-up (DLB n = 837 and PDD n = 157). Results: When adjusting for confounders, we found no difference in the annual change in MMSE between DLB and PDD (−1.8 [95% CI −2.3, −1.3] vs. −1.9 [95% CI −2.6, −1.2] [P = 0.74]). MDS-UPDRS part III showed nearly identical annual changes (DLB 4.8 [95% CI 2.1, 7.5]) (PDD 4.8 [95% CI 2.7, 6.9], [P = 0.98]). Conclusions: DLB and PDD showed similar rates of cognitive and motor decline. This is relevant for future clinical trial designs