Page 255 - MEGIN Book Of Abstracts - 2023

lyzed of 146 MS patients, and 100 patients had a 5-year Neuroscience Institute, Université libre de Bruxelles (ULB),
follow-up neuropsychological assessment. Network Bruxelles, Belgium; Magnetoencephalography Unit, Depart-
properties of the minimum spanning tree (i.e. back- ment of Functional Neuroimaging, Service of Nuclear Medi-
bone of the functional brain network) indicating net- cine, CUB-Hôpital Erasme, Bruxelles, Belgium; Department of
work integration and overload were related to baseline Neurology, UZ Brussels, Bruxelles, Belgium; Oxford University
and longitudinal cognition, correcting for structural Centre for Functional MRI of the Brain (FMRIB), University
damage. of Oxford, Oxford, UK; St Edmund Hall, University of Oxford,
Oxford, UK
RESULTS A more integrated beta band network (i.e.
smaller diameter) and a less integrated delta band ABSTRACT Working memory (WM) problems are fre-
network (i.e. lower leaf fraction) predicted cognitive quently present in people with multiple sclerosis (MS).
decline after 5 years (Radj2=15%), independent of Even though hippocampal damage has been repeat-
structural damage. Cross-sectional analyses showed edly shown to play an important role, the underlying
that a less integrated network (e.g. lower tree hierarchy) neurophysiological mechanisms remain unclear. This
related to worse cognition, independent of frequency study aimed to investigate the neurophysiological
band. underpinnings of WM impairment in MS using mag-
netoencephalography (MEG) data from a visual-verbal
CONCLUSIONS The level of functional brain network 2-back task. We analysed MEG recordings of 79 MS
integration was an independent predictive marker of patients and 38 healthy subjects through event-related
cognitive decline, in addition to the severity of structur- fields and theta (4-8 Hz) and alpha (8-13 Hz) oscillatory
al damage. This work thereby indicates the promise of processes. Data was source reconstructed and parcel-
MEG-derived network measures in predicting disease lated based on previous findings in the healthy subject
progression in MS. sample. MS patients showed a smaller maximum theta
power increase in the right hippocampus between 0
Keywords: Multiple sclerosis, cognitive functioning, longi- and 400 ms than healthy subjects (p = .014). This theta
tudinal, magnetic resonance imaging, magnetoencepha- power increase value correlated negatively with reac-
lography, network organization tion time on the task in MS (r = -.32, p = .029). Evidence
was provided that this relationship could not be ex-
Multiple sclerosis (Houndmills, Basingstoke, England) plained by a 'common cause' confounding relationship
(2021), Vol. 27, No. 11 (33295249) (7 citations) with MS-related neuronal damage. This study provides
the first neurophysiological evidence of the influence of
hippocampal dysfunction on WM performance in MS.
The role of hippocampal theta oscillations in
working memory impairment in multiple sclerosis Keywords: hippocampus, magnetoencephalography,
(2021) multiple sclerosis, n-back, theta, working memory

Costers, Lars; Van Schependom, Jeroen; Laton, Jorne; Human brain mapping (2021), Vol. 42, No. 5 (33247542) (5
Baijot, Johan; Sjøgård, Martin; Wens, Vincent; De Tiège, citations)
Xavier; Goldman, Serge; D'Haeseleer, Miguel; D'hooghe,
Marie Beatrice; Woolrich, Mark; Nagels, Guy
Brain dysconnectivity relates to disability and
AIMS Lab, Center For Neurosciences, UZ Brussel, Vrije Univer- cognitive impairment in multiple sclerosis (2021)
siteit Brussel, Brussel, Belgium; Departement of Radiology,
UZ Brussel, Brussel, Belgium; Nuffield Department of Clinical Sjøgård, Martin; Wens, Vincent; Van Schependom,
Neurosciences, University of Oxford, Oxford, UK; Laboratoire Jeroen; Costers, Lars; D'hooghe, Marie; D'haeseleer,
de Cartographie Fonctionnelle du Cerveau (LCFC), UNI-ULB Miguel; Woolrich, Mark; Goldman, Serge; Nagels, Guy;

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