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Related Concept Videos

Epilepsy and Seizures: Overview01:24

Epilepsy and Seizures: Overview

Epilepsy is a chronic neurological disease marked by recurrent, unpredictable seizures. These seizures are caused by abnormal electrical discharges in the brain, leading to behavior, sensation, or consciousness alterations. They can also cause transient impairment of awareness, interfering with daily activities.
Various factors can trigger epilepsy, including genetic factors, brain damage, metabolic causes, and unknown etiology. Diagnosis of epilepsy involves electroencephalography (EEG), which...
Seizures l: Introduction01:20

Seizures l: Introduction

Understanding seizures and epilepsy relies on key definitions that help in recognizing, classifying, and managing these disorders. These definitions provide a framework for recognizing, classifying, and managing seizure disorders.DefinitionsA seizure is a sudden, abnormal burst of electrical activity in the brain that can cause changes in awareness, movement, sensation, or behavior, depending on the area involved. Epilepsy is a chronic condition characterized by recurrent, unprovoked seizures,...
Brain Waves01:23

Brain Waves

Brain waves are electrical signals generated by the neurons in the brain, which are regularly monitored to measure mental activities. Brain waves and their frequency ranges can be measured using an electroencephalogram or EEG. There are four main types of brain waves, each with distinct characteristics:
Epilepsy ll: Types01:22

Epilepsy ll: Types

Recurrent seizures, stemming from abnormal electrical activity in the brain, are the defining characteristic of epilepsy, a chronic neurological condition. Because seizure features vary greatly, epilepsy is classified using two systems: by seizure type and by epilepsy syndromes. These classifications enable clinicians to describe seizure patterns and select suitable treatment strategies.I. Classification by Seizure Type1. Focal EpilepsyFocal epilepsy begins in one hemisphere of the brain.
Seizures: Classification01:13

Seizures: Classification

Epilepsy is primarily characterized by unpredictable seizures, either provoked by an identifiable factor, such as injury or illness, or unprovoked, occurring spontaneously without apparent cause.
Seizures are typically classified into two main categories: focal and generalized seizures.
Focal Seizures
Focal seizures originate from specific regions of the brain. These seizures are further sub-classified into two types:

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Related Experiment Video

Updated: Jun 17, 2026

High-Quality Seizure-Like Activity from Acute Brain Slices Using a Complementary Metal-Oxide-Semiconductor High-Density Microelectrode Array System
06:28

High-Quality Seizure-Like Activity from Acute Brain Slices Using a Complementary Metal-Oxide-Semiconductor High-Density Microelectrode Array System

Published on: September 27, 2024

Electrographic high-frequency activity and epilepsy.

Premysl Jiruska1, Andrew D Powell, Wei-Chih Chang

  • 1Neuroscience, School of Clinical and Experimental Medicine, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, United Kingdom.

Epilepsy Research
|December 25, 2009
PubMed
Summary
This summary is machine-generated.

High-frequency electrographic activity (HFA), a marker of epilepsy, is reviewed. Understanding HFA generation mechanisms is crucial for epilepsy research and treatment localization.

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Interictal High Frequency Oscillations Detected with Simultaneous Magnetoencephalography and Electroencephalography as Biomarker of Pediatric Epilepsy
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Interictal High Frequency Oscillations Detected with Simultaneous Magnetoencephalography and Electroencephalography as Biomarker of Pediatric Epilepsy

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Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue
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Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue

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Last Updated: Jun 17, 2026

High-Quality Seizure-Like Activity from Acute Brain Slices Using a Complementary Metal-Oxide-Semiconductor High-Density Microelectrode Array System
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Interictal High Frequency Oscillations Detected with Simultaneous Magnetoencephalography and Electroencephalography as Biomarker of Pediatric Epilepsy
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Interictal High Frequency Oscillations Detected with Simultaneous Magnetoencephalography and Electroencephalography as Biomarker of Pediatric Epilepsy

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Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue
13:14

Multi-electrode Array Recordings of Human Epileptic Postoperative Cortical Tissue

Published on: October 26, 2014

Area of Science:

  • Neuroscience
  • Epileptology

Background:

  • High-frequency electrographic activity (HFA), ranging from 80-600Hz, is observed in epilepsy.
  • HFA occurs both between seizures (interictally) and at seizure onset.
  • Its generation mechanisms are hypothesized to be key to epileptogenesis and ictogenesis.

Purpose of the Study:

  • To review the current understanding of high-frequency electrographic activity (HFA).
  • To discuss the role of HFA in epilepsy.
  • To highlight future research challenges concerning HFA.

Main Methods:

  • Literature review of high-frequency electrographic activity (HFA).
  • Analysis of HFA's presence in epileptic foci and during seizures.
  • Examination of hypotheses regarding HFA generation.

Main Results:

  • HFA is a specific electrographic marker found in epileptic foci.
  • HFA is utilized in presurgical evaluations for epilepsy focus localization.
  • Current knowledge on HFA generation and its role in epilepsy is synthesized.

Conclusions:

  • High-frequency electrographic activity (HFA) is a significant biomarker in epilepsy.
  • Further research into HFA generation mechanisms is needed.
  • HFA plays a critical role in localizing epileptic foci for surgical planning.