Brain state may help predict how people with epilepsy respond to electrical stimulation, a study suggests.
Researchers found that the same electrical stimulation could have markedly different effects depending on patterns of brain activity immediately beforehand.
The results suggest that timing treatment according to a patient’s current brain activity could make neuromodulation more consistent. Neuromodulation uses electrical or magnetic stimulation to alter nerve activity.
Researchers analysed recordings from 36 people with epilepsy who underwent intracranial electrical stimulation as part of clinically indicated procedures to map areas involved in seizures.
The dataset, hosted on the EBRAINS Knowledge Graph, included around 320 recording sessions and more than 10,000 individual stimulations.
Recordings were made using stereoelectroencephalography, or SEEG, in which electrodes placed inside the brain measure electrical activity, alongside high-density EEG, which uses electrodes on the scalp.
The team examined 125 measures of brain activity recorded before each stimulus, including communication and synchronisation between different brain regions and the complexity of electrical signals.
Whole-brain patterns predicted responses more accurately than recordings taken from individual locations.
Predictions were strongest when brain networks involved in movement, sensation and vision were stimulated.
Selecting trials based on particular patterns of activity before stimulation reduced variation in responses by up to 24 per cent.
Similar predictive patterns were found using both electrodes inside the brain and non-invasive scalp recordings.
The researchers said the results could support future approaches that monitor brain activity in real time to help determine when stimulation should be delivered.
Brain stimulation techniques are already used in research and to treat conditions including Parkinson’s disease, epilepsy and depression, but responses can vary considerably even when the stimulation site and settings are the same.
The results could help researchers examine whether adapting stimulation to a person’s changing brain state can make such treatments more consistent and reliable.
