Publications by authors named "C Degueldre"

145 Publications

In vivo exploration of synaptic projections in frontotemporal dementia.

Sci Rep 2021 Aug 9;11(1):16092. Epub 2021 Aug 9.

GIGA Cyclotron Research Centre, University of Liège, B30 Sart Tilman, 4000, Liège, Belgium.

The purpose of this exploratory research is to provide data on synaptopathy in the behavioral variant of frontotemporal dementia (bvFTD). Twelve patients with probable bvFTD were compared to 12 control participants and 12 patients with Alzheimer's disease (AD). Loss of synaptic projections was assessed with [F]UCBH-PET. Total distribution volume was obtained with Logan method using carotid artery derived input function. Neuroimages were analyzed with SPM12. Verbal fluency, episodic memory and awareness of cognitive impairment were equally impaired in patients groups. Compared to controls, [F]UCBH uptake tended to decrease in the right anterior parahippocampal gyrus of bvFTD patients. Loss of synaptic projections was observed in the right hippocampus of AD participants, but there was no significant difference in [F]UCBH brain uptake between patients groups. Anosognosia for clinical disorder was correlated with synaptic density in the caudate nucleus and the anteromedial prefrontal cortex. This study suggests that synaptopathy in bvFTD targets the temporal social brain and self-referential processes.
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http://dx.doi.org/10.1038/s41598-021-95499-1DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8352914PMC
August 2021

Familiarity in Mild Cognitive Impairment as a Function of Patients' Clinical Outcome 4 Years Later.

Alzheimer Dis Assoc Disord 2021 Jul 23. Epub 2021 Jul 23.

GIGA-Cyclotron Research Centre In Vivo Imaging, University of Liège F.R.S.-National Funds for Scientific Research Belgium Centre Hospitalier du Bois de l'Abbaye et de Hesbaye Memory Clinic, CHU Liège, Liège, Belgium.

Objectives: The current study addresses the nature of memory difficulties in amnestic mild cognitive impairment (aMCI). Whereas recollection is consistently found to be impaired in aMCI, the results on familiarity are divergent. One potential factor that could explain this divergence in findings relates to the heterogeneity of aMCI patients, so that only those aMCI patients who develop Alzheimer disease (AD) may present with impaired familiarity. The present study aimed at testing this hypothesis.

Methods: A group of 45 aMCI patients and a group of 26 healthy older adults performed a verbal recognition memory test with the Remember/Know paradigm to assess recollection and familiarity processes. All participants were followed for 4 years with clinical and neuropsychological testing. At the end of follow-up, 22 aMCI patients progressed to AD and 23 aMCI patients remained stable. Initial memory performance was compared between the 3 groups.

Results: Whereas recollection was severely diminished in all aMCI patients, familiarity accuracy (and consequently global recognition accuracy) was found to be impaired only in aMCI patients who subsequently developed AD.

Conclusion: These findings suggest that the enrichment of the aMCI population with predementia stage patients may modulate the likelihood to observe familiarity deficits, and impaired global recognition accuracy may accompany incipient AD.
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http://dx.doi.org/10.1097/WAD.0000000000000466DOI Listing
July 2021

Corrigendum to: Incidental Verbal Semantic Processing Recruits the Fronto-temporal Semantic Control Network.

Cereb Cortex 2021 Aug;31(10):4864

GIGA - Cyclotron Research Centre in vivo imaging, University of Liège, 4000 Liège, Belgium.

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http://dx.doi.org/10.1093/cercor/bhab250DOI Listing
August 2021

Parkinson's disease multimodal imaging: F-DOPA PET, neuromelanin-sensitive and quantitative iron-sensitive MRI.

NPJ Parkinsons Dis 2021 Jul 8;7(1):57. Epub 2021 Jul 8.

GIGA-CRC In Vivo Imaging, University of Liège, Liège, Belgium.

Parkinson's disease (PD) is a neurodegenerative synucleinopathy characterized by the degeneration of neuromelanin (NM)-containing dopaminergic neurons and deposition of iron in the substantia nigra (SN). How regional NM loss and iron accumulation within specific areas of SN relate to nigro-striatal dysfunction needs to be clarified. We measured dopaminergic function in pre- and postcommissural putamen by [F]DOPA PET in 23 Parkinson's disease patients and 23 healthy control (HC) participants in whom NM content and iron load were assessed in medial and lateral SN, respectively, by NM-sensitive and quantitative R2* MRI. Data analysis consisted of voxelwise regressions testing the group effect and its interaction with NM or iron signals. In PD patients, R2* was selectively increased in left lateral SN as compared to healthy participants, suggesting a local accumulation of iron in Parkinson's disease. By contrast, NM signal differed between PD and HC, without specific regional specificity within SN. Dopaminergic function in posterior putamen decreased as R2* increased in lateral SN, indicating that dopaminergic function impairment progresses with iron accumulation in the SN. Dopaminergic function was also positively correlated with NM signal in lateral SN, indicating that dopaminergic function impairment progresses with depigmentation in the SN. A complex relationship was detected between R2* in the lateral SN and NM signal in the medial SN. In conclusion, multimodal imaging reveals regionally specific relationships between iron accumulation and depigmentation within the SN of Parkinson's disease and provides in vivo insights in its neuropathology.
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http://dx.doi.org/10.1038/s41531-021-00199-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8266835PMC
July 2021

Incidental Verbal Semantic Processing Recruits the Fronto-temporal Semantic Control Network.

Cereb Cortex 2021 Jun 28. Epub 2021 Jun 28.

GIGA - Cyclotron Research Centre in vivo imaging, University of Liège, 4000 Liège, Belgium.

The frontoparietal semantic network, encompassing the inferior frontal gyrus and the posterior middle temporal cortex, is considered to be involved in semantic control processes. The explicit versus implicit nature of these control processes remains however poorly understood. The present study examined this question by assessing regional brain responses to the semantic attributes of an unattended stream of auditory words while participants' top-down attentional control processes were absorbed by a demanding visual search task. Response selectivity to semantic aspects of verbal stimuli was assessed via a functional magnetic resonance imaging response adaptation paradigm. We observed that implicit semantic processing of an unattended verbal stream recruited not only unimodal and amodal cortices in posterior supporting semantic knowledge areas, but also inferior frontal and posterior middle temporal areas considered to be part of the semantic control network. These results indicate that frontotemporal semantic networks support incidental semantic (control) processes.
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http://dx.doi.org/10.1093/cercor/bhab169DOI Listing
June 2021
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