Objective EEG Bed Side Assessment of Impaired Conscious Awareness in Epilepsy

Study Overview
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Brief Summary
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In this project EEG recordings between healthy participants and those with a diagnosed Absence-epilepsy will be compared. The investigators suggest differences in EEG microstate analysis and neuropsychological parameters related to interictal cognitive impairment in these patients. This projects goal is to derive an EEG-based measure of conscious awareness.

Detailed Description
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This projects goal is to derive an EEG-based measure of conscious awareness to be applied in the care for epilepsy patients. The established terminology of ictal versus interictal is deceptive because it suggests that during the interictal phase epileptic activity is absent and detrimental mechanisms of the disease are only active during seizures. But evidence exists that cognitive impairment extends to states traditionally considered interictal. The development of an objective, ideally ambulatory test assessing cognitive impairment would not only provide a deeper understanding of the pathology but induce a change in clinical practice: if cognitive impairment could be demonstrated interictally, this fact would help to weigh treatment effects against potential side-effects. In this project the investigators will set out to identify EEG markers in healthy volunteers, which reflect the changes in spatial and temporal dynamics of neuronal activity during states of reduced conscious awareness using sleep as an example of a state of reduced conscious awareness; assess with neuropsychological testing reductions in interictal conscious awareness in patients with epilepsy; test, whether markers established under (1) are valid in individuals with epilepsy and interictally reduced conscious awareness (see (2)).

Official Title
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Objective EEG Bed Side Assessment of Impaired Conscious Awareness in Epilepsy

Conditions
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Epilepsy, Absence

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: age minimum 18 years diagnosis of (absence) epilepsy // healthy age-matched controls being of good health (besides epilepsy in the case group) Exclusion Criteria: central nervous system disorders (besides epilepsy in the case group) substance abuse pregnancy

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| healthy subjects<br>Age-matched healthy participants will be recruited via flyers at public education facilities and online advertisement. Participants need to be healthy and without central nervous system disorders and substance abuse. The investigators will also exclude pregnant women from the experiment. | |
| patients with absence epilepsy<br>Apart from the diagnosis of epilepsy, patients need to be of good health and without central nervous system disorders and substance abuse. The investigators will also exclude pregnant women from the experiment. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| temporal integration changes according to different sleep states | The investigators develop an EEG-based measure of impaired conscious awareness based on wakefulness and deepening sleep stages which will serve as a model for increasingly impaired conscious awareness. By performing a microstate analysis on EEG data, the investigators hypothesize a decrease of the temporal integration, a prerequisite for conscious awareness, of the EEG gradually from wakefulness to deep sleep. | 3 years | 
| temporal integration changes in interictal EEG | The investigators apply the aforementioned analysis (leading to Outcome 1) on interictal EEG recordings obtained from patients with diagnosed absence epilepsy. The investigators hypothesize a reduced temporal integration in epilepsies with reduced consciousness. | 3 years | 
| graph modularity changes according to different sleep states | The investigators will calculate the EEG-based functional connectivity and graph modularity for each sleep state. The investigators hypothesize that during wakefulness, graph modularity will be lower than during the descent to sleep. | 3 years | 
| graph modularity changes in interictal EEG | The investigators will calculate the EEG-based functional connectivity and graph modularity for the absence epilepsy condition. The investigators hypothesize that impaired consciousness will be reflected in lower graph modularity compared to healthy subjects. | 3 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| EEG based measures (Outcome 4) correlate with | The investigators hypothesize that the graph modularity level correlates with neuropsychological test scores in the surveyed data of epilepsy patients. | 3 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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interictal activity, impaired consciousness, absence epilepsy