Visualizing Ripples and Fast Ripples in Scalp and Intracranial EEG

Ripples (80-200 Hz) and Fast Ripples (200-600 Hz) are brief (15-200 msec) bursts of spectral energy that can occur superimposed on inter-ictal or ictal epileptiform spikes or superimposed on the EEG background. Both ripples and fast ripples may delineate regions that are necessary and sufficient for seizures known as the epileptogenic zone and correspond with disease severity. Natus® BRAIN QUICK® can visualize ripples and fast ripples and distinguish these events from artifact. BRAIN QUICK plug-ins can quantify and automatically annotate each ripple, fast ripple, and spike event for higher-level custom analysis approaches using Python or Matlab.

Learning Objectives:

• Ripples (80-200 Hz) and fast ripples (200-600 Hz) occur superimposed on epileptiform spikes or the EEG background in scalp EEG, intracranial EEG, and the local field potential.
• Ripples that occur on the EEG background may be an admixture of normal and pathological events. Ripples superimposed on epileptiform spikes and fast ripples found in the EEG background or superimposed on epileptiform spikes are most often pathological events.
• Identifying ripples and fast ripples should be performed during non-REM sleep, during wakefulness muscle artifact can lead to false ripple and fast ripple detections. Software can be used to validate the detections and make redactions.
• Fast ripples may indicate the synchronization of pathological neuron clusters that can prime epileptiform spikes and seizures. Data show that surgeries that target fast ripple correlate with seizure free post-operative seizure outcome.

ASET approval for 1.0 CEC