Functional Connectivity Alterations of the Temporal Lobe and Hippocampus in Semantic Dementia and Alzheimer’s Disease

Schwab, Simon; Afyouni, Soroosh; Chen, Yan; Han, Zaizhu; Guo, Qihao; Dierks, Thomas; Wahlund, Lars-Olof; Grieder, Matthias (2020). Functional Connectivity Alterations of the Temporal Lobe and Hippocampus in Semantic Dementia and Alzheimer’s Disease. Journal of Alzheimer's disease, 76(4), pp. 1461-1475. IOS Press 10.3233/JAD-191113

[img]
Preview
Text
Schwab_etal_jad191113_prepress.pdf - Accepted Version
Available under License Creative Commons: Attribution-Noncommercial (CC-BY-NC).

Download (555kB) | Preview
[img]
Preview
Text
Schwab_etal_FC in AD and SD_JAD_2020.pdf - Published Version
Available under License Creative Commons: Attribution-Noncommercial (CC-BY-NC).

Download (1MB) | Preview

Background: Semantic memory impairments in semantic dementia are attributed to atrophy and functional disruption of the anterior temporal lobes. In contrast, the posterior medial temporal neurodegeneration found in Alzheimer’s disease is associated with episodic memory disturbance. The two dementia subtypes share hippocampal deterioration, despite a relatively spared episodic memory in semantic dementia.
Objective: To unravel mutual and divergent functional alterations in Alzheimer’s disease and semantic dementia, we assessed functional connectivity between temporal lobe regions in Alzheimer’s disease (n = 16), semantic dementia (n = 23), and healthy controls (n = 17).
Methods: In an exploratory study, we used a functional parcellation of the temporal cortex to extract time series from 66 regions for correlation analysis.
Results: Apart from differing connections between Alzheimer’s disease and semantic dementia that yielded reduced functional connectivity, we identified a common pathway between the right anterior temporal lobe and the right orbitofrontal cortex in both dementia subtypes. This disconnectivity might be related to social knowledge deficits as part of semantic memory decline. However, such interpretations are preferably made in a holistic context of disease-specific semantic impairments and functional connectivity changes.
Conclusion: Despite a major limitation owed to unbalanced databases between study groups, this study provides a preliminary picture of the brain’s functional disconnectivity in Alzheimer’s disease and semantic dementia. Future studies are needed to replicate findings of a common pathway with consistent diagnostic criteria and neuropsychological evaluation, balanced designs, and matched data MRI acquisition procedures.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > University Psychiatric Services > University Hospital of Psychiatry and Psychotherapy > Translational Research Center

UniBE Contributor:

Dierks, Thomas and Grieder, Matthias

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1387-2877

Publisher:

IOS Press

Funders:

[4] Swiss National Science Foundation
[UNSPECIFIED] Beijing Natural Science Foundation
[UNSPECIFIED] NSFC
[UNSPECIFIED] Alzheimer fonden
[UNSPECIFIED] Swiss Synapsis Foundation
[UNSPECIFIED] University of Bern

Language:

English

Submitter:

Matthias Grieder

Date Deposited:

20 Jul 2020 10:54

Last Modified:

25 Aug 2020 12:04

Publisher DOI:

10.3233/JAD-191113

PubMed ID:

32651312

BORIS DOI:

10.7892/boris.145264

URI:

https://boris.unibe.ch/id/eprint/145264

Actions (login required)

Edit item Edit item
Provide Feedback