Resilience of developing brain networks to interictal epileptiform discharges is associated with cognitive outcome

Ibrahim, George M.; Cassel, Daniel; Morgan, Benjamin R.; Smith, Mary Lou; Otsubo, Hiroshi; Ochi, Ayako; Taylor, Margot J.; Rutka, James T.; Snead, O. Carter; Doesburg, Sam M.

doi:10.1093/brain/awu214

Cited by 93 publications

(94 citation statements)

References 56 publications

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“…[38][39][40][41] Furthermore, a relationship between changes in EEG network topology and the IED frequency was found. 41 Whether IEDs in turn affect functional connectivity is under debate. We found a stress-sensitivity driven correlation between cortisol and IED frequency and functional connectivity and an overall correlation between functional connectivity and IED frequency, irrespective of stress sensitivity.…”

Section: Cortisol and Functional Connectivitymentioning

confidence: 85%

The relation between cortisol and functional connectivity in people with and without stress‐sensitive epilepsy

et al. 2017

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SummaryObjective: The most common reported seizure-precipitant is stress. We recently showed a biologic basis for stress sensitivity of seizures: cortisol levels in people with stress-sensitive epilepsy correlated with focal interictal epileptiform discharges (IEDs) on electroencephalography (EEG). Here we aimed to determine whether the effect of cortisol on the epileptic brain is global or focal, and whether cortisol affects all brains or just those of stress-sensitive people. Because epilepsy is associated with changes in functional brain connectivity, we studied the relationship between cortisol and changes in global and focal (node-centered) functional connectivity measures for individuals with stress-sensitive and non-stresssensitive epilepsy. Methods: Seventeen people with epilepsy underwent long-term (>24 h) EEG recording. During the first 5 h after waking, saliva was collected every 15 min for cortisol measurements. Theta-band functional connectivity was assessed for every 15 min of the recording. We calculated the average phase-lag index (PLI) between all channels as a measure of global functional connectivity. We used network Strength, the averaged PLI per channel, as focal functional connectivity measure. We correlated cortisol, global, and focal functional connectivity (Strength) with IED frequency using linear mixed models. Analyses were split for people with and without stress-sensitivity of seizures. Results: Cortisol was negatively correlated with global functional connectivity in people with stress-sensitive seizures (estimate À0.0020; P < .01), whereas not in those without stress-sensitivity (estimate À0.0003; P = .46). This relationship occurred irrespective of the presence of IEDs on a channel (channels without IEDs and stress-sensitivity: estimate À0.0019; P < .01, non-stress-sensitive À0.0003; P = .41). Global and focal functional connectivity were negatively correlated with IED frequency, irrespective of stress sensitivity of seizures or channel type. Significance: People with stress-sensitive epilepsy have a whole-brain neuronal response to cortisol that is different from that of people with non-stress-sensitive epilepsy. This offers a basis for understanding seizure genesis in stress-sensitive epilepsy, which might require a different treatment approach.

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Section: Cortisol and Functional Connectivitymentioning

confidence: 85%

The relation between cortisol and functional connectivity in people with and without stress‐sensitive epilepsy

et al. 2017

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“…При эпилептических энцефалопатиях эпилептическая активность сама по себе может способствовать возникновению тяже-лых когнитивных и поведенческих нарушений кроме и сверх тех нарушений, которые являются ожидаемы-ми при самом заболевании (например, при кортикаль-ных мальформациях) и которые с течением времени могут ухудшаться [22]. Механизмы влияния эпилепти-формной интериктальной активности на когнитивные функции недостаточно изучены, однако считается, что такие разряды оказывают повреждающее влияние на межнейронные взаимодействия во внутренних ней-ронных сетях мозга [44].…”

Section: Ch I Ld Neurology R U S S I a N J O U R N A L O Funclassified

The Formation of Cognitive and Mental Disorders in Epilepsy: The Role of Various Factors Associated With Disease and Treatment (A Review of Literature and Case Reports)

Мухин¹,

Пылаева²

2017

Rus. ž. det. nevrol.

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“…A recent study showed disrupted SN in relation to inter-ictal spikes in children with focal (temporal and extra-temporal) intractable epilepsy (Ibrahim et al, 2014). In addition, it has been observed that thalamic deactivation is associated with inter-ictal discharges in generalised epilepsy (Wang et al, 2012b).…”

Section: Discussionmentioning

confidence: 99%

“…Although previous studies examined salience network changes in heterogeneous groups of patients (focal and generalised epilepsy), whereas in our study, we only investigated a homogenous group of MTLE, findings from those studies can support each other. It has been previously suggested that large-scale network changes in relation to spikes can be applied across different clinical variables for epilepsy (Ibrahim et al, 2014). Also, previous work examining prespike related BOLD changes revealed that BOLD signal changes were identifiable prior to interictal spikes in focal (Jacobs et al, 2009) and generalised (Moeller et al, 2008) epilepsy.…”

Section: Discussionmentioning

confidence: 99%

The epileptogenic network: the relationship between resting state and pre-spike related perturbations

Faizo¹

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Mesial Temporal Lobe Epilepsy (MTLE) is the most common symptomatic focal epilepsy, with hippocampal sclerosis (HS) representing the most commonly occurring pathology linked to MTLE.In the past HS has been understood to represent a focal neuropathological alteration linked to the generation of seizures (i.e., the epileptic focus). However, the phenomenon that not all patients become seizure-free after surgical resection of the hippocampus has given rise to the concept that seizures and interictal epileptiform spikes and sharp waves (IES) captured by electroencephalography (EEG) in MTLE result from activity in a functionally connected epileptogenic network of brain regions. Large-scale network dynamics may thus be involved in the generation of IES and the temporal synchronisation of network structures may be an important factor in spike generation. Surgical outcome may be improved by broadening the focus from the identification of a single epileptogenic region to the characterisation of temporally synchronous epileptogenic networks associated with spikes.A common way to identify functional networks is to assess functional connectivity (FC) between spatially distinct brain regions. FC measures the degree of covariance between the activity in a specific brain region and other areas across the whole brain. The simultaneous acquisition of EEG and functional magnetic resonance imaging (fMRI) enables the identification of functional networks in which haemodynamic changes are time-locked to spikes. Nevertheless, whether this reflects the propagation of neural activity from a 'focus', or conversely the activation of a network linked to spike generation remains controversial. Delineation of functional connectivity patterns related to IES may be useful in shedding light on the mechanisms underlying their generation, and potentially of seizures in MTLE. Although the exact physiologic relationship between IES and seizures is not fully understood, there is a growing evidence to suggest that the neural network involved in generating IES is a reliable estimator of the network that generates seizures.My PhD aimed to explore the changes in brain network function that predispose the generation of IES using EEG-fMRI in patients with MTLE. I collected EEG-fMRI data from two groups of subjects: patients with MTLE and healthy controls. First, I examined MTLE patients to assess the presence of altered functional network connectivity identifiable immediately prior to the appearance of interictal spikes on EEG. A fundamental finding was the significant loss of bilateral hippocampal

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Resilience of developing brain networks to interictal epileptiform discharges is associated with cognitive outcome

Cited by 93 publications

References 56 publications

The relation between cortisol and functional connectivity in people with and without stress‐sensitive epilepsy

The relation between cortisol and functional connectivity in people with and without stress‐sensitive epilepsy

The Formation of Cognitive and Mental Disorders in Epilepsy: The Role of Various Factors Associated With Disease and Treatment (A Review of Literature and Case Reports)

The epileptogenic network: the relationship between resting state and pre-spike related perturbations

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