What does the presence of multifocal spikes in an EEG indicate?

The presence of multifocal spikes in an EEG is indicative of abnormal electrical activity occurring in multiple regions of the brain. This pattern is often associated with focal epilepsy, which is characterized by seizures that originate in a specific location within one hemisphere of the brain. Multifocal spikes signal that there may be disturbances in neuronal firing across different foci, increasing the likelihood of seizure activity related to localized brain dysfunction.

This finding contrasts with generalized seizure activity, where the electrical disturbances are spread uniformly across the entire brain, leading to different spike characteristics. Normal brain activity typically does not exhibit spikes, and potential structural abnormalities may not be solely determined by the presence of multifocal spikes without further investigation, such as imaging studies. Thus, multifocal spikes are most closely associated with an elevated risk for focal epilepsy.