8 research outputs found
Le stress chez les enfants avec convulsions fébriles : mécanismes et contribution au pronostic
Le stress est continuellement associĂ© Ă la genĂšse, la frĂ©quence et la sĂ©vĂ©ritĂ© des convulsions en Ă©pilepsie. De nombreux modĂšles animaux suggĂšrent quâune relation entre le stress et les convulsions soit mise en place en dĂ©but de vie, voire dĂšs la pĂ©riode prĂ©natale. Or, il existe peu de preuves de cette hypothĂšse chez lâhumain. Ainsi, lâobjectif gĂ©nĂ©ral de cette thĂšse Ă©tait dâexaminer le lien entre le stress en dĂ©but de vie, dĂšs la conception, et les convulsions chez les humains. Pour ce faire, cette thĂšse avait comme intĂ©rĂȘt principal les convulsions fĂ©briles (CF). Il sâagit de convulsions pĂ©diatriques communes et somme toute bĂ©nignes, bien quâelles soient associĂ©es Ă de lĂ©gĂšres particularitĂ©s neurologiques et cognitives. En ce sens, les CF reprĂ©sentent un syndrome de choix pour notre Ă©tude, considĂ©rant leur incidence frĂ©quente en trĂšs bas Ăąge et lâabsence de consĂ©quences majeures Ă long terme. Ainsi, elles permettent lâĂ©tude de la relation entre le stress en dĂ©but de vie et les convulsions par lâentremise dâun relativement grand bassin populationnel, en rĂ©duisant lâimpact de potentiels facteurs confondants.
Dans ce contexte, notre objectif gĂ©nĂ©ral a Ă©tĂ© Ă©tudiĂ© par lâentremise de cinq objectifs secondaires. Dâabord, le premier objectif secondaire de cette thĂšse Ă©tait de faire le point sur la littĂ©rature expliquant le lien entre les convulsions, le stress, ainsi que lâimpact que pourrait avoir le stress sur le pronostic cognitif des syndromes convulsifs (article 1).
Le second Ă©tait dâexaminer la relation entre les symptĂŽmes maternels auto-rapportĂ©s de stress, dâanxiĂ©tĂ© spĂ©cifique Ă la grossesse ou de dĂ©pression durant la grossesse et la pĂ©riode postpartum et les CF. Par le biais dâun devis longitudinal, les rĂ©sultats de cette thĂšse suggĂšrent quâune plus forte anxiĂ©tĂ© spĂ©cifique Ă la grossesse ainsi quâune plus grande prĂ©sence de symptĂŽmes dĂ©pressifs en pĂ©riode postnatale sont associĂ©es Ă une diminution du seuil convulsif des CF, caractĂ©risĂ©e par un plus jeune Ăąge lors du premier Ă©pisode convulsif (article 2).
ĂtudiĂ© Ă travers ce mĂȘme devis longitudinal, le troisiĂšme objectif secondaire de cette thĂšse Ă©tait dâĂ©valuer le lien entre des changements biologiques associĂ©s Ă lâexposition au stress prĂ©natal et les CF. Or, nos rĂ©sultats mettent plutĂŽt en lumiĂšre des diffĂ©rences sur le plan du systĂšme sĂ©rotoninergique placentaire, sous-tendant une exposition ou une propension au stress. Dâune part, ces changements seraient associĂ©s Ă une hausse de lâincidence des CF et, dâautre part, Ă une baisse du seuil convulsif (article 3).
Par ailleurs, le quatriĂšme sous-objectif couvert par cette thĂšse Ă©tait dâĂ©tudier la rĂ©ponse biologique de stress chez des enfants avec antĂ©cĂ©dents de CF afin de voir si elle se distingue de celle dâenfants sans antĂ©cĂ©dents convulsifs. Notre Ă©tude appariĂ©e suggĂšre une plus forte sensibilitĂ© au stress chez les enfants avec antĂ©cĂ©dents de CF « simple » (article 4). Ainsi, ces rĂ©sultats ne dĂ©montrent pas de changements systĂ©matiques Ă lâensemble des enfants sur le plan de la rĂ©activitĂ© au stress. Toutefois, des changements chez les enfants avec CF simples pourraient sous-tendre des anomalies prĂ©morbides.
Accessoirement, durant lâĂ©tude du quatriĂšme sous-objectif, nous nâavons pas Ă©tĂ© en mesure dâidentifier des anomalies cognitives dans les mois suivants un Ă©pisode de CF, ni dâassocier le pronostic cognitif au profil de rĂ©activitĂ© au stress. Dans ce contexte, le cinquiĂšme et dernier objectif secondaire visait Ă investiguer le pronostic Ă©lectrophysiologique des CF et Ă en Ă©tudier lâassociation avec la rĂ©activitĂ© au stress. Les rĂ©sultats suggĂšrent la prĂ©sence de particularitĂ©s Ă©lectrophysiologiques chez les enfants avec antĂ©cĂ©dents de CF « complexes », lesquelles pourraient ĂȘtre associĂ©es aux altĂ©rations cognitives vues chez cette population Ă long terme (article 5). Par-dessus tout, notons que ces particularitĂ©s diffĂšrent en fonction du sous-type de CF complexes. Toutefois, les rĂ©sultats obtenus dans le cadre de notre devis expĂ©rimental nâont pas Ă©tĂ© en mesure dâidentifier un rĂŽle du stress sur ces atypies (addenda).
Ensemble, ces rĂ©sultats suggĂšrent lâexistence dâun lien entre le stress en dĂ©but de vie, dĂšs la pĂ©riode prĂ©natale, et les CF. Ils appuient lâimportance dâinvestiguer le stress prĂ©natal, postnatal et actuel en contexte de syndromes convulsifs en gĂ©nĂ©ral, dont les CF. En raison de lâimpact considĂ©rable du stress sur la qualitĂ© de vie des personnes vivant avec un syndrome convulsif, une meilleure caractĂ©risation de la relation entre le stress prĂ©coce et les convulsions pourrait Ă long terme mener au dĂ©veloppement dâinterventions prĂ©coces et non invasives. Par ailleurs, mĂȘme si ces rĂ©sultats nâont pas Ă©tĂ© en mesure dâidentifier une relation entre la rĂ©activitĂ© au stress et le pronostic cognitif ou Ă©lectrophysiologique des CF, lâĂ©tude de ce lien est nĂ©anmoins suggĂ©rĂ©e par les Ă©tudes animales et devrait faire lâobjet dâĂ©tudes futures.Stress is a phenomenon frequently associated with epileptogenesis and increased seizure frequency and severity. Animal studies suggest the relationship between stress and seizures may begin early in life, maybe even prenatally. Evidence showing a link between early programming through stress and seizure disorders has yet to be found in humans. Hence, the general objective of this thesis was to examine the relationship between early-life stress, including the prenatal period, and seizures in humans. For this purpose, the prime focus of this research was on febrile seizures (FS). FS are common and benign pediatric seizures, associated only with mild neurological and cognitive peculiarities. Due to their frequent incidence in early childhood and lack of severe consequences, they allow for the investigation of the relationship between early-life stress and seizures through a relatively large sample, while reducing the impact of potential confounding variables.In this context, our general objective was investigated through five sub-objectives. First, we aimed toreview the current knowledge on the link between seizures and stress, as well as the impact stress could have on the cognitive prognosis of seizure disorders (1starticle).The second sub-objective was to study the relationship between self-reported maternal emotion distress during both the pregnancy and postpartum period, on FS. Through a longitudinal cohort, this research supports increased prenatal pregnancy-specific anxiety and postpartum depressive symptoms are associated with a lowered FS threshold, as shown through a younger age at first FS occurrence (2ndarticle). Moreover, the third sub-objective, which was studied through the same longitudinal research, was to evaluate how biological changes associated with prenatal exposure to stress may be linked to FS. This study showed changes in the placental serotoninergic system are found in children with FS history. More precisely, these changes are associated with increased FS incidence, and lowered FS threshold (3rdarticle). On the other hand, the fourth sub-objective of this thesis was to study the biological stress response of children with past FS, compared to that of children without personal history of seizures. Our case-control study suggested only children with âsimpleâ FS showed increased sensibility to stress (4tharticle). Hence, these results do not show systematic changes in the
ivbiological stress reaction of all children with FS. Still, they do show changes in some children, which could be premorbid to the first FS episode.Incidentally, while studying the fourth sub-objective, we were unable to show changes in the developmental skills of children with FS, nor did we show an interaction with stress reactivity. Hence, the fifth and final subjective of this thesis was to investigate the electrophysiological prognosis of children with past FS, and its association with stress reactivity. Our results show differences in the electrophysiological profile of children with âcomplexâ FS only, which could be linked to cognitive alterations in the long-term (5tharticle). Moreover, we showed these abnormalities differ depending on the type of complex FS. Still, we were unable to identify an additive or interactive link with stress reactivity (addendum). Taken together, these results highlight the existence of a link between stress, starting in the prenatal period, and FS. Hence, they highlight the importance of investigating prenatal, postnatal and current stress in the context of seizure disorders at large, including FS. Given the significant impact of stress on the quality of life of people living with epilepsy, increased knowledge on the link between early stress and seizures could lead to the development of early and non-invasive treatments targeting stress in the future. Moreover, although these results do not show stress to be associated with altered cognitive or electrophysiological prognosis in the context of FS, this link is nevertheless supported by animal research and should be the subject of future studie
Prolonged and unprolonged complex febrile seizures differently affect frontal theta brain activity
Objective: Studies have identified persistent cognitive and functional deficits, which could be
linked to each other, in children with complex febrile seizures (FS). Our aim was to investigate
differences in brain activity in children with a history of complex FS, through a study paradigm
associated with the development of learning capacities and using electroencephalographic
(EEG) signal. To further increase our understanding of these differences, complex FS were
studied separately depending on their type.
Method: EEG was recorded in 43 children with past FS. Brain activity associated with auditory
learning was investigated using a habituation paradigm, in which repetition suppression (RS) is
typically found following stimulus repetition. Auditory stimuli were repeated three times, and
each presentation were analysed separately in the time-frequency (TF) domain. A mixedanalysis of variance was used to assess differences in spectral power between stimulus repetition
and FS type (simple vs complex prolonged; CP vs complex unprolonged; CUP).
Results: Repetition effects were found in the 3-6 Hz during 150-600ms time window after
stimulus onset at frontal sites (F(2, 40)=5.645, p=0.007, η2p=0.220). Moreover, an interaction
effect between stimulus repetition and FS type (F(4, 80)=2.607, p=0.042, η2p=0.115) was
found. Children with CP FS showed greater increase in spectral power in response to the first
stimulus presentation, while children with CUP FS failed to show a RS pattern.
Significance: Our results show distinct abnormalities in brain activity to a habituation paradigm.
We argue that these changes suggest children with CP FS may be hyperexcitable, while children
with CUP FS show impaired habituation processes. Still, these differences may be associated
with other clinical features linked to complex FS as well. Hence, the role of these differences in
complex FS incidence and prognosis should be the subject of future studies
Effects of eight neuropsychiatric copy number variants on human brain structure
Many copy number variants (CNVs) confer risk for the same range of neurodevelopmental symptoms and psychiatric conditions including autism and schizophrenia. Yet, to date neuroimaging studies have typically been carried out one mutation at a time, showing that CNVs have large effects on brain anatomy. Here, we aimed to characterize and quantify the distinct brain morphometry effects and latent dimensions across 8 neuropsychiatric CNVs. We analyzed T1-weighted MRI data from clinically and non-clinically ascertained CNV carriers (deletion/duplication) at the 1q21.1 (nâ=â39/28), 16p11.2 (nâ=â87/78), 22q11.2 (nâ=â75/30), and 15q11.2 (nâ=â72/76) loci as well as 1296 non-carriers (controls). Case-control contrasts of all examined genomic loci demonstrated effects on brain anatomy, with deletions and duplications showing mirror effects at the global and regional levels. Although CNVs mainly showed distinct brain patterns, principal component analysis (PCA) loaded subsets of CNVs on two latent brain dimensions, which explained 32 and 29% of the variance of the 8 Cohenâs d maps. The cingulate gyrus, insula, supplementary motor cortex, and cerebellum were identified by PCA and multi-view pattern learning as top regions contributing to latent dimension shared across subsets of CNVs. The large proportion of distinct CNV effects on brain morphology may explain the small neuroimaging effect sizes reported in polygenic psychiatric conditions. Nevertheless, latent gene brain morphology dimensions will help subgroup the rapidly expanding landscape of neuropsychiatric variants and dissect the heterogeneity of idiopathic conditions
DĂ©veloppement cognitif des enfants Ă©pileptiques : contribution du stress
LâĂ©pilepsie est un dĂ©sordre neurologique souvent infantile associĂ© Ă des
comorbidités qui impliquent des troubles cognitifs. Depuis quelques
années, les études des chercheurs suggÚrent que la qualité de vie des
personnes atteintes dâĂ©pilepsie est plus sĂ©vĂšrement impactĂ©e par les
comorbidités associées à la maladie que par les crises. Il importe donc
de diminuer la sévérité des troubles cognitifs chez les personnes
Ă©pileptiques. Dans cet article, nous relevons les hypothĂšses de la
littĂ©rature actuelle qui stipulent que le stress pourrait ĂȘtre un facteur
affectant négativement le développement cognitif des enfants
épileptiques. Ainsi, nous décrivons les atteintes neuropsychologiques
inhérentes aux syndromes convulsifs, la relation biologique du stress et
la relation entre le stress et les syndromes convulsifs. Deux modes
dâaction, Ă©voquĂ©s par les chercheurs, par lesquels le stress serait un
facteur aggravant les comorbidités des personnes qui présentent un
syndrome convulsif seront aussi dĂ©crits.Epilepsy is a neurodevelopmental disorder with an onset mainly during childhood, and is linked to life-long cognitive deficits. In this article, we suggest that stress could negatively influence the cognitive development in children suffering from epilepsy. The object of this article is to present two explanations that are complementary and cumulative regarding the link between stress and cognitive development in epileptic children and to review the current knowledge regarding them. First, stress influences seizuresâ frequency and severity, which influences cognitive development. Secondly, stress causes cognitive deficits which might be added to the cognitive deficits caused by seizures
Age at first febrile seizure correlates with perinatal maternal emotional symptoms
Objective: Prenatal exposure to stress and fever are factors lowering seizure threshold in animal models. The
fever effect on seizure threshold is well documented in human infants, however the associations between maternal
perinatal stress and infantsâ susceptibility to seizures is unknown. This is the first study in humans to
investigate longitudinally, whether in humans, the effect of maternal perinatal emotional symptoms such as
stress, anxiety and depression that may trigger a biological stress response on age at first seizure occurrence.
Method: The study sample is a subgroup drawn from a longitudinal follow up cohort (3D cohort study: Design,
Develop, Discover, N= 2366 mother-infant dyads). Twenty-nine otherwise healthy infants who had a febrile
seizure (FS) episode before the last follow-up visit (around 24 months of age) were studied. Mothers completed
questionnaires regarding their emotional health at each pregnancy trimester and at three months postpartum.
The link between maternal emotional symptoms and infant age at first FS was assessed through correlations and
multiple regressions.
Results: We found that maternal anxiety symptoms during the second trimester of pregnancy are linked to the
age at first FS (r(23) =â0.459, p =0.021) and explain 21.1% of its variance. Postnatal maternal depression
symptoms at 3 months postpartum were also associated with the age at first FS (r(23) =â0.587, p= 0.002)
and explained an additional 17.6% of variance. Together, the variables explained 38.7% of the variance in age at
first FS. Maternal perceived stress symptoms at 3 months postpartum were also linked to the age at first FS (r
(23) =â0.418, p=0.038), however, stress did not significantly contribute to the variance of age at first FS..
Significance: Our results suggest a link between increased perinatal maternal emotional symptoms and the age at
first FS. An earlier age at first FS may be the manifestation of a lower seizure threshold. Early first seizure
occurrence is a risk factor for compromised neurological and cognitive development. Further studies should
address the mechanisms by which perinatal maternal emotional symptoms may have an impact on seizure
threshold in humans
Febrile seizures and increased stress sensitivity in children : how it relates to seizure characteristics
BACKGROUND: Studies suggest that the relationship between seizures and stress starts early in life. However, evidence of long-term altered stress reactivity following early-life seizures is lacking. Our objectives were to assess alterations in stress hormone reactivity in children with past febrile seizures (FS) and investigate how these alterations relate to clinical characteristics. METHOD: This case-control study compared a convenience sample of children with simple FS (nâŻ=âŻ24), complex FS (nâŻ=âŻ18), and matched healthy controls (nâŻ=âŻ42). Stress was induced by electrode placement for an electroencephalography (EEG) exam. Salivary cortisol to stress, using three samples collected before and after the stressor, was compared between groups and sex. The relationship between stress reactivity and clinical characteristics (i.e., FS duration, age at first FS, time since the last FS) was investigated. RESULTS: Cortisol reactivity to stress was significantly different depending on study groups, F(1, 78)âŻ=âŻ6.415, pâŻ=âŻ0.003, η2pâŻ=âŻ0.141, but not sex nor was there a significant interaction between group and sex (pâŻâ„âŻ0.581). Participants with simple FS showed higher cortisol reactivity to stress (MâŻ=âŻ14.936, Standard deviation (SD)âŻ=âŻ26.852) compared with those with complex FS (MâŻ=âŻ-4.663, SDâŻ=âŻ18.649, pâŻ=âŻ0.015) and controls (MâŻ=âŻ-3.817, SDâŻ=âŻ18.907, pâŻ=âŻ0.003). There was no significant difference between participants with complex FS and controls (pâŻ>âŻ0.999). Stress reactivity was not linked to clinical characteristics. CONCLUSIONS: Children with past simple FS showed greater changes in salivary cortisol following stress, suggesting enhanced stress sensitivity. As similar results were not found in a population with complex FS, our study shows that stress alterations are not caused by seizure severity. Future studies are needed to investigate whether stress sensitivity may be premorbid to simple FS and may contribute to simple FS incidence
Effects of eight neuropsychiatric copy number variants on human brain structure.
Many copy number variants (CNVs) confer risk for the same range of neurodevelopmental symptoms and psychiatric conditions including autism and schizophrenia. Yet, to date neuroimaging studies have typically been carried out one mutation at a time, showing that CNVs have large effects on brain anatomy. Here, we aimed to characterize and quantify the distinct brain morphometry effects and latent dimensions across 8 neuropsychiatric CNVs. We analyzed T1-weighted MRI data from clinically and non-clinically ascertained CNV carriers (deletion/duplication) at the 1q21.1 (n = 39/28), 16p11.2 (n = 87/78), 22q11.2 (n = 75/30), and 15q11.2 (n = 72/76) loci as well as 1296 non-carriers (controls). Case-control contrasts of all examined genomic loci demonstrated effects on brain anatomy, with deletions and duplications showing mirror effects at the global and regional levels. Although CNVs mainly showed distinct brain patterns, principal component analysis (PCA) loaded subsets of CNVs on two latent brain dimensions, which explained 32 and 29% of the variance of the 8 Cohen's d maps. The cingulate gyrus, insula, supplementary motor cortex, and cerebellum were identified by PCA and multi-view pattern learning as top regions contributing to latent dimension shared across subsets of CNVs. The large proportion of distinct CNV effects on brain morphology may explain the small neuroimaging effect sizes reported in polygenic psychiatric conditions. Nevertheless, latent gene brain morphology dimensions will help subgroup the rapidly expanding landscape of neuropsychiatric variants and dissect the heterogeneity of idiopathic conditions