Epilepsy is recognised as a dynamic disease, where seizures and their features change over time. Specifically, we recently demonstrated that seizures themselves change in terms of their evolution. However, the underpinning modulators of seizure evolution remain unclear. In this work, we analyse continuous (interictal ) intracranial Electroencephalographic (iEEG) recordings , and elucidate fluctuations in iEEG band power over different timescales ( ranging from minutes to days) . We find that all patients show an approximately circadian fluctuation in their EEG band power, but also many other fluctuations on patient-specific timescales. Importantly, we find that a combination of fluctuations on different timescales can explain the changes in seizure evolution in most patients above chance-level. We interpret these results as evidence that seizure modulating factors exist, and they vary over time (patient-specifically). These time-varying modulating factors can be captured in fluctuations of EEG band power , and future work should link them to the exact biological time-varying processes  .
Epilepsy is recognised as a dynamic disease, where susceptibility to seizures and seizure characteristics change over time. Specifically, we recently found variable seizure dynamics within individual patients. Additionally, the variability appeared to follow subject-specific circadian or longer timescale modulations. However, whether signatures of these modulations over different timescales can be captured on continuous (interictal) EEG remains unclear. In this work, we analyse continuous interictal intracranial electroencephalographic (iEEG) recordings from video-telemetry units and find fluctuations in iEEG band power over different timescales ranging from minutes up to twelve days . We find that all subjects show not only an approximately-circadian fluctuation in their EEG band power, but also many other fluctuations on subject-specific timescales. Importantly, we find that a combination of fluctuations on different timescales can explain changes in seizure network evolution in a regression model in most subjects above chance level. These results suggest that subject-specific fluctuations in iEEG band power over timescales of minutes to days are associated with how seizures are modulated over time. Future work is needed to link the detected fluctuations to the exact biological time-varying processes . Understanding seizure modulating factors enables development of novel treatment strategies that minimise the seizure spread, duration, or severity and therefore clinical impact of seizures .
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seizures and their features
susceptibility to seizures and seizure characteristics
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demonstrated that seizures themselves change in terms of their evolution. However, the underpinning modulators of seizure evolution remain
found variable seizure dynamics within individual patients. Additionally, the variability appeared to follow subject-specific circadian or longer timescale modulations. However, whether signatures of these modulations over different timescales can be captured on continuous (interictal) EEG remains
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(interictal ) intracranial Electroencephalographic
interictal intracranial electroencephalographic
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, and elucidate
from video-telemetry units and find
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(
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to days)
up to twelve days
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patients show an approximately circadian
subjects show not only an approximately-circadian
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patient-specific
subject-specific
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the
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evolution in most patients above chance-level. We interpret these results as evidence that seizure modulating factors exist, and they vary over time (patient-specifically). These time-varying modulating factors can be captured in fluctuations of EEG band power , and future work should link them
network evolution in a regression model in most subjects above chance level. These results suggest that subject-specific fluctuations in iEEG band power over timescales of minutes to days are associated with how seizures are modulated over time. Future work is needed to link the detected fluctuations
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. Understanding seizure modulating factors enables development of novel treatment strategies that minimise the seizure spread, duration, or severity and therefore clinical impact of seizures