Journal of Alzheimer's disease : JAD
-
Case Reports
Alzheimer's Disease FDG PET Imaging Pattern in an Amyloid-Negative Mild Cognitive Impairment Subject.
The revised NIA-AA diagnostic criteria for Alzheimer's disease (AD) and mild cognitive impairment (MCI) due to AD make use of amyloid pathology and neurodegeneration biomarkers which increase the diagnostic confidence in the majority of patients. However, in daily praxis, cases with conflicting biomarker constellations occur. ⋯ In this subject, the biomarkers of Aβ deposition were negative. [18F]FDG PET, however, showed an AD-typical hypometabolism. Further studies are required to determine frequency and relevance of cases with neurodegeneration-first biomarker constellations to improve our understanding on pathogenesis and diagnosis of AD.
-
Comparative Study
Mirror Image of the Amyloid-β Species in Cerebrospinal Fluid and Cerebral Amyloid in Alzheimer's Disease.
Alzheimer's disease (AD) is characterized by amyloid-β (Aβ) accumulation in brain that is paralleled by Aβ(1-42) reduction in cerebrospinal fluid (CSF). We analyzed the pattern of Aβ peptides, including the N- and C-terminal truncated fragments, in brain and CSF from two familial and one sporadic AD cases. We found that (i) each patient is characterized by a distinct Aβ profile in CSF and brain deposits and (ii) the CSF Aβ pattern mirrors the Aβ profile of cerebral amyloid. These results suggest the existence of different molecular AD subtypes which can be recognized by CSF analysis, enabling patient stratification.
-
There is growing evidence that the human brain is a large scale complex network. The structural network is reported to be disrupted in cognitively impaired patients. However, there have been few studies evaluating the effects of amyloid and small vessel disease (SVD) markers, the common causes of cognitive impairment, on structural networks. ⋯ Greater white matter hyperintensity volumes or lacunae numbers were significantly associated with decreased network integration (increased shortest path length, decreased global efficiency) and increased network segregation (increased clustering coefficient, increased transitivity, increased modularity). Decreased network integration or increased network segregation were associated with poor performances in attention, language, visuospatial, memory, and frontal-executive functions. Our results suggest that SVD alters white matter network integration and segregation, which further predicts cognitive dysfunction.
-
The two non-semantic variants of primary progressive aphasia (PPA), nonfluent/agrammatic PPA (nfv-PPA) and logopenic variant PPA (lv-PPA), share language features despite their different underlying pathology, and may be difficult to distinguish for non-language experts. ⋯ Non-language presenting features can help differentiate between the two non-semantic PPA syndromes, with a double dissociation observed on tasks of episodic memory and emotion processing. Based on performance on these tasks, we propose a decision tree as a complementary method to differentiate between the two non-semantic variants. These findings have important clinical implications, with identification of patients who may potentially benefit existing therapeutic interventions currently available for Alzheimer's disease.
-
Destination memory, or the ability to remember the destination to whom a piece of information was addressed, is found to be compromised in Alzheimer's disease (AD). Our paper investigated the relationship between destination memory and theory of mind in AD since both destination memory and theory of mind are social abilities that require processing attributes of interlocutors. ⋯ Significant correlations were observed between destination memory, and 1st and 2nd order cognitive theory of mind in AD participants and controls. By demonstrating a relationship between compromises in 2nd order theory of mind and in destination memory, our work highlights links between social cognition and memory functioning in AD.