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Vesna Jelic

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9 papers

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YNICL Journal 2026 Journal Article

Cognitive adaptations for memory deficits in MCI and AD patients: A meta-analysis of EEG microstates

Timothy Piton
Una Smailovic
Vesna Jelic
Thomas Koenig
Paul G. Unschuld
Lucie Bréchet

AIM: EEG microstate analysis enables the exploration of the brain's neuronal network activity associated with distinct mental states and cognitive functions in neurodegenerative conditions, such as Alzheimer's disease (AD). Some studies indicated that AD and patients with mild cognitive impairments (MCI) show a reduced presence of microstate C, which is related to self-related memory functions and mind-wandering and involves brain areas of the default mode network (DMN). However, other studies reported an increased presence of microstate A, which is associated with auditory/language functions. Here, we aimed to systematically investigate alterations in the four canonical EEG microstates (A, B, C, and D) in MCI and AD patients compared to healthy older adults. METHODS: We performed a meta-analysis that compared microstate temporal parameters - mean duration, occurrence rate, and time coverage - among MCI and AD patients and healthy older adults. We included 12 experimental studies that examined resting-state, eyes-closed EEG microstate parameters in 1347 participants (448 MCI patients, 514 AD patients, and 385 healthy controls). RESULTS: We found thatAD patients showed increased duration and time coverage of microstate A and increased duration of microstate B, while the occurrence of microstates C and D was reduced. MCI patients also exhibited increased duration, occurrence, and time coverage of microstate A, while all three parameters of microstate D were reduced compared to healthy controls. CONCLUSION: These results suggest that MCI and AD patients suffer from disruption in their cognitive control, memory, and self-referential processes. They may compensate for these deficits by verbalizing and visualizing their inner thoughts to maintain cognitive engagement.

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YNICL Journal 2025 Journal Article

Selective association of EEG microstates with clinical symptoms and mutation status in monogenic Alzheimer disease

Charlotte Johansson
Thomas Koenig
Una Smailovic
Vanessa Hallström
Vesna Jelic
Caroline Graff

EEG microstates are transient and short-lasting periods of stable scalp potential fields that are associated with disturbed temporal dynamics of large-scale brain networks, affected by early synaptic loss in Alzheimer disease (AD). We investigated changes in EEG microstates in presymptomatic (PMC) and symptomatic mutation carriers (SMC) compared to healthy non-carrier (NC) controls in families with autosomal dominant AD (ADAD). A total of 99 EEG recordings from 7 SMC, 17 PMC and 24 NC were selected from a Swedish ADAD cohort. Seven classes (A to G) of microstate topographical maps were fitted to their resting-state EEG. Next, microstate parameters of coverage (fraction of total recording time), duration (average time in milliseconds) and occurrence (frequency per second) of different topographical maps were assessed in repeated-measures analyses to compare differences between NC, PMC and SMC. Selective decreases in coverage of class B (SMC vs NC, p = 0.023) and class C (SMC vs PMC and NC, p = 0.017 and p = 0.004) were observed in symptomatic individuals. In contrast, mutation carriers had a decrease in coverage of class D (SMC and PMC vs NC, p = 0.015 and p = 0.001) and an increase in coverage of class E compared to controls (SMC and PMC vs NC, both p = 0.001). Thus, global brain network dynamics as described by EEG microstate classes were selectively affected in this cohort of monogenic AD, associated with either clinical symptoms (class B and C) or mutation status (class D and E). The latter suggests early mutation-related changes that are detectable already in the presymptomatic stages of disease.

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YNICL Journal 2021 Journal Article

Differential early subcortical involvement in genetic FTD within the GENFI cohort

Martina Bocchetta
Emily G. Todd
Georgia Peakman
David M. Cash
Rhian S. Convery
Lucy L. Russell
David L. Thomas
Juan Eugenio Iglesias

BACKGROUND: Studies have previously shown evidence for presymptomatic cortical atrophy in genetic FTD. Whilst initial investigations have also identified early deep grey matter volume loss, little is known about the extent of subcortical involvement, particularly within subregions, and how this differs between genetic groups. METHODS: 480 mutation carriers from the Genetic FTD Initiative (GENFI) were included (198 GRN, 202 C9orf72, 80 MAPT), together with 298 non-carrier cognitively normal controls. Cortical and subcortical volumes of interest were generated using automated parcellation methods on volumetric 3 T T1-weighted MRI scans. Mutation carriers were divided into three disease stages based on their global CDR® plus NACC FTLD score: asymptomatic (0), possibly or mildly symptomatic (0.5) and fully symptomatic (1 or more). RESULTS: In all three groups, subcortical involvement was seen at the CDR 0.5 stage prior to phenoconversion, whereas in the C9orf72 and MAPT mutation carriers there was also involvement at the CDR 0 stage. In the C9orf72 expansion carriers the earliest volume changes were in thalamic subnuclei (particularly pulvinar and lateral geniculate, 9-10%) cerebellum (lobules VIIa-Crus II and VIIIb, 2-3%), hippocampus (particularly presubiculum and CA1, 2-3%), amygdala (all subregions, 2-6%) and hypothalamus (superior tuberal region, 1%). In MAPT mutation carriers changes were seen at CDR 0 in the hippocampus (subiculum, presubiculum and tail, 3-4%) and amygdala (accessory basal and superficial nuclei, 2-4%). GRN mutation carriers showed subcortical differences at CDR 0.5 in the presubiculum of the hippocampus (8%). CONCLUSIONS: C9orf72 expansion carriers show the earliest and most widespread changes including the thalamus, basal ganglia and medial temporal lobe. By investigating individual subregions, changes can also be seen at CDR 0 in MAPT mutation carriers within the limbic system. Our results suggest that subcortical brain volumes may be used as markers of neurodegeneration even prior to the onset of prodromal symptoms.

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YNICL Journal 2021 Journal Article

Disease-related cortical thinning in presymptomatic granulin mutation carriers

Sergi Borrego-Écija
Roser Sala-Llonch
John van Swieten
Barbara Borroni
Fermín Moreno
Mario Masellis
Carmela Tartaglia
Caroline Graff

Mutations in the granulin gene (GRN) cause familial frontotemporal dementia. Understanding the structural brain changes in presymptomatic GRN carriers would enforce the use of neuroimaging biomarkers for early diagnosis and monitoring. We studied 100 presymptomatic GRN mutation carriers and 94 noncarriers from the Genetic Frontotemporal dementia initiative (GENFI), with MRI structural images. We analyzed 3T MRI structural images using the FreeSurfer pipeline to calculate the whole brain cortical thickness (CTh) for each subject. We also perform a vertex-wise general linear model to assess differences between groups in the relationship between CTh and diverse covariables as gender, age, the estimated years to onset and education. We also explored differences according to TMEM106B genotype, a possible disease modifier. Whole brain CTh did not differ between carriers and noncarriers. Both groups showed age-related cortical thinning. The group-by-age interaction analysis showed that this age-related cortical thinning was significantly greater in GRN carriers in the left superior frontal cortex. TMEM106B did not significantly influence the age-related cortical thinning. Our results validate and expand previous findings suggesting an increased CTh loss associated with age and estimated proximity to symptoms onset in GRN carriers, even before the disease onset.

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YNICL Journal 2019 Journal Article

EEG time signature in Alzheimer´s disease: Functional brain networks falling apart

Una Smailovic
Thomas Koenig
Erika J Laukka
Grégoria Kalpouzos
Thomas Andersson
Bengt Winblad
Vesna Jelic

Spontaneous mental activity is characterized by dynamic alterations of discrete and stabile brain states called functional microstates that are thought to represent distinct steps of human information processing. Electroencephalography (EEG) directly reflects functioning of brain synapses with a uniquely high temporal resolution, necessary for investigation of brain network dynamics. Since synaptic dysfunction is an early event and best correlate of cognitive status and decline in patients along Alzheimer's disease (AD) continuum, EEG microstates might serve as valuable early markers of AD. The present study investigated differences in EEG microstate topographies and parameters (duration, occurrence and contribution) between a large cohort of healthy elderly (n = 308) and memory clinic patients: subjective cognitive decline (SCD, n = 210); mild cognitive impairment (MCI, n = 230) and AD (n = 197) and how they correlate to conventional cerebrospinal fluid (CSF) markers of AD. Four most representative microstate maps assigned as classes A, B (asymmetrical), C and D (symmetrical) were computed from the resting state EEGs since it has been shown previously that this is sufficient to explain most of the resting state EEG data. Statistically different topography of microstate maps were found between the controls and the patient groups for microstate classes A, C and D. Changes in the topography of microstate class C were associated with the CSF Aβ42 levels, whereas changes in the topography of class B were linked with the CSF p-tau levels. Gradient-like increase in the contribution of asymmetrical (A and B) and gradient-like decrease in the contribution of symmetrical (C and D) maps were observed with the more severe stage of cognitive impairment. Our study demonstrated extensive relationship of resting state EEG microstates topographies and parameters with the stage of cognitive impairment and AD biomarkers. Resting state EEG microstates might therefore serve as functional markers of early disruption of neurocognitive networks in patients along AD continuum.

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YNIMG Journal 2019 Journal Article

Spatiotemporal analysis for detection of pre-symptomatic shape changes in neurodegenerative diseases: Initial application to the GENFI cohort

Claire Cury
Stanley Durrleman
David M. Cash
Marco Lorenzi
Jennifer M. Nicholas
Martina Bocchetta
John C. van Swieten
Barbara Borroni

Brain atrophy as measured from structural MR images, is one of the primary imaging biomarkers used to track neurodegenerative disease progression. In diseases such as frontotemporal dementia or Alzheimer's disease, atrophy can be observed in key brain structures years before any clinical symptoms are present. Atrophy is most commonly captured as volume change of key structures and the shape changes of these structures are typically not analysed despite being potentially more sensitive than summary volume statistics over the entire structure. In this paper we propose a spatiotemporal analysis pipeline based on Large Diffeomorphic Deformation Metric Mapping (LDDMM) to detect shape changes from volumetric MRI scans. We applied our framework to a cohort of individuals with genetic variants of frontotemporal dementia and healthy controls from the Genetic FTD Initiative (GENFI) study. Our method, take full advantage of the LDDMM framework, and relies on the creation of a population specific average spatiotemporal trajectory of a relevant brain structure of interest, the thalamus in our case. The residuals from each patient data to the average spatiotemporal trajectory are then clustered and studied to assess when presymptomatic mutation carriers differ from healthy control subjects. We found statistical differences in shape in the anterior region of the thalamus at least five years before the mutation carrier subjects develop any clinical symptoms. This region of the thalamus has been shown to be predominantly connected to the frontal lobe, consistent with the pattern of cortical atrophy seen in the disease.

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YNIMG Journal 2019 Journal Article

The inner fluctuations of the brain in presymptomatic Frontotemporal Dementia: The chronnectome fingerprint

Enrico Premi
Vince D. Calhoun
Matteo Diano
Stefano Gazzina
Maura Cosseddu
Antonella Alberici
Silvana Archetti
Donata Paternicò

Frontotemporal Dementia (FTD) is preceded by a long period of subtle brain changes, occurring in the absence of overt cognitive symptoms, that need to be still fully characterized. Dynamic network analysis based on resting-state magnetic resonance imaging (rs-fMRI) is a potentially powerful tool for the study of preclinical FTD. In the present study, we employed a "chronnectome" approach (recurring, time-varying patterns of connectivity) to evaluate measures of dynamic connectivity in 472 at-risk FTD subjects from the Genetic Frontotemporal dementia research Initiative (GENFI) cohort. We considered 249 subjects with FTD-related pathogenetic mutations and 223 mutation non-carriers (HC). Dynamic connectivity was evaluated using independent component analysis and sliding-time window correlation to rs-fMRI data, and meta-state measures of global brain flexibility were extracted. Results show that presymptomatic FTD exhibits diminished dynamic fluidity, visiting less meta-states, shifting less often across them, and travelling through a narrowed meta-state distance, as compared to HC. Dynamic connectivity changes characterize preclinical FTD, arguing for the desynchronization of the inner fluctuations of the brain. These changes antedate clinical symptoms, and might represent an early signature of FTD to be used as a biomarker in clinical trials.

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YNICL Journal 2019 Journal Article

White matter hyperintensities in progranulin-associated frontotemporal dementia: A longitudinal GENFI study

Carole H. Sudre
Martina Bocchetta
Carolin Heller
Rhian Convery
Mollie Neason
Katrina M. Moore
David M. Cash
Ione O.C. Woollacott

Frontotemporal dementia (FTD) is a heterogeneous group of neurodegenerative disorders with both sporadic and genetic forms. Mutations in the progranulin gene (GRN) are a common cause of genetic FTD, causing either a behavioural presentation or, less commonly, language impairment. Presence on T2-weighted images of white matter hyperintensities (WMH) has been previously shown to be more commonly associated with GRN mutations rather than other forms of FTD. The aim of the current study was to investigate the longitudinal change in WMH and the associations of WMH burden with grey matter (GM) loss, markers of neurodegeneration and cognitive function in GRN mutation carriers. 336 participants in the Genetic FTD Initiative (GENFI) study were included in the analysis: 101 presymptomatic and 32 symptomatic GRN mutation carriers, as well as 203 mutation-negative controls. 39 presymptomatic and 12 symptomatic carriers, and 73 controls also had longitudinal data available. Participants underwent MR imaging acquisition including isotropic 1 mm T1-weighted and T2-weighted sequences. WMH were automatically segmented and locally subdivided to enable a more detailed representation of the pathology distribution. Log-transformed WMH volumes were investigated in terms of their global and regional associations with imaging measures (grey matter volumes), biomarker concentrations (plasma neurofilament light chain, NfL, and glial fibrillary acidic protein, GFAP), genetic status (TMEM106B risk genotype) and cognition (tests of executive function). Analyses revealed that WMH load was higher in both symptomatic and presymptomatic groups compared with controls and this load increased over time. In particular, lesions were seen periventricularly in frontal and occipital lobes, progressing to medial layers over time. However, there was variability in the WMH load across GRN mutation carriers - in the symptomatic group 25.0% had none/mild load, 37.5% had medium and 37.5% had a severe load - a difference not fully explained by disease duration. GM atrophy was strongly associated with WMH load both globally and in separate lobes, and increased WMH burden in the frontal, periventricular and medial regions was associated with worse executive function. Furthermore, plasma NfL and to a lesser extent GFAP concentrations were seen to be associated with increased lesion burden. Lastly, the presence of the homozygous TMEM106B rs1990622 TT risk genotypic status was associated with an increased accrual of WMH per year. In summary, WMH occur in GRN mutation carriers and accumulate over time, but are variable in their severity. They are associated with increased GM atrophy and executive dysfunction. Furthermore, their presence is associated with markers of WM damage (NfL) and astrocytosis (GFAP), whilst their accrual is modified by TMEM106B genetic status. WMH load may represent a target marker for trials of disease modifying therapies in individual patients but the variability across the GRN population would prevent use of such markers as a global outcome measure across all participants in a trial.

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YNICL Journal 2017 Journal Article

White matter hyperintensities are seen only in GRN mutation carriers in the GENFI cohort

Carole H. Sudre
Martina Bocchetta
David Cash
David L. Thomas
Ione Woollacott
Katrina M. Dick
John van Swieten
Barbara Borroni

Genetic frontotemporal dementia is most commonly caused by mutations in the progranulin (GRN), microtubule-associated protein tau (MAPT) and chromosome 9 open reading frame 72 (C9orf72) genes. Previous small studies have reported the presence of cerebral white matter hyperintensities (WMH) in genetic FTD but this has not been systematically studied across the different mutations. In this study WMH were assessed in 180 participants from the Genetic FTD Initiative (GENFI) with 3D T1- and T2-weighed magnetic resonance images: 43 symptomatic (7 GRN, 13 MAPT and 23 C9orf72), 61 presymptomatic mutation carriers (25 GRN, 8 MAPT and 28 C9orf72) and 76 mutation negative non-carrier family members. An automatic detection and quantification algorithm was developed for determining load, location and appearance of WMH. Significant differences were seen only in the symptomatic GRN group compared with the other groups with no differences in the MAPT or C9orf72 groups: increased global load of WMH was seen, with WMH located in the frontal and occipital lobes more so than the parietal lobes, and nearer to the ventricles rather than juxtacortical. Although no differences were seen in the presymptomatic group as a whole, in the GRN cohort only there was an association of increased WMH volume with expected years from symptom onset. The appearance of the WMH was also different in the GRN group compared with the other groups, with the lesions in the GRN group being more similar to each other. The presence of WMH in those with progranulin deficiency may be related to the known role of progranulin in neuroinflammation, although other roles are also proposed including an effect on blood-brain barrier permeability and the cerebral vasculature. Future studies will be useful to investigate the longitudinal evolution of WMH and their potential use as a biomarker as well as post-mortem studies investigating the histopathological nature of the lesions.

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