Abstract

To identify clinical and neuroimaging characteristics between posterior cortical atrophy (PCA) and typical amnestic Alzheimer’s disease (tAD) patients at an early disease stage, 16 PCA and 13 age-matched tAD patients were enrolled. Compared with tAD patients, PCA patients showed higher mean recognition and recall test scores, and lower mean calculation, spatial attention, shape discrimination, and writing test scores. Mean right hippocampal volume was larger in PCA patients compared with tAD patients, while cortical gray matter (GM) volume of bilateral parietal and occipital lobes was smaller in PCA patients. Further, when compared with tAD patients, significant hypometabolism was observed in bilateral parietal and occipital lobes, particularly the right occipitotemporal junction in PCA patients. Additionally, there were significant positive correlations in recognition and recall scores with hippocampal volumes. In PCA patients, calculation and visuospatial ability scores are positively associated with GM volume of parietal and occipital lobes. And only spatial attention and shape discrimination scores are positively associated with regional glucose metabolism of parietal and occipital lobes. Therefore, PCA patients display better recognition and recall scores, which are associated with larger hippocampal volumes and poorer performance in visual spatial tasks because of marked GM atrophy and hypometabolism of parietal and occipital lobes.

Highlights

  • Lobe atrophy is an early feature in tAD, yet atrophy is detected in posterior areas such as the precuneus and posterior cingulate gyrus[14]

  • Our study provides important information regarding the clinical manifestation, patterns of cerebral atrophy, Alzheimer’s disease (AD) biomarker levels, and regional glucose metabolism in posterior cortical atrophy (PCA) and tAD patients at an early disease stage

  • Compared with tAD patients, PCA patients show more symptoms related to the visual cortex, and exhibit marked impairments in visuospatial-related cognitive function

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Summary

Introduction

Lobe atrophy is an early feature in tAD, yet atrophy is detected in posterior areas such as the precuneus and posterior cingulate gyrus[14]. Compared with tAD patients, PCA patients show greater atrophy in the right occipitotemporal cortex[15]. Voxel-based image analysis of 18F-fluoro-deoxyglucose-PET (FDG-PET) in tAD patients suggests the earliest hypometabolic regions occurs in the posterior cingulate cortex and mesial temporal structures[16]. The difference of neurocognitive and neuroimaging characteristic between PCA and tAD patients in Chinese population is largely unknown, and for the correlation between the neuropsychological tests performance and the atrophic or hypometabolic regions in these patients[19]. Differences in clinical manifestations, biomarker levels, regional atrophy, and glucose metabolism between the groups were compared, with the possible relationship between neuropsychological tests performance and neuroimaging characteristics in PCA patients further analyzed

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