Does stereoelectroencephalographic depth electrode insertion alter seizure frequency? A baseline versus endpoint...

Area of Science:

• Neurology
• Neurosurgery
• Epilepsy Research

Background:

• The implantation effect is a temporary decrease in seizure frequency post-intracranial electrode insertion.
• This phenomenon occurs independently of any therapeutic interventions in epilepsy patients.

Purpose of the Study:

• To investigate clinical and demographic predictors of the implantation effect.
• To analyze seizure reduction rates and explore potential mechanisms behind this effect.

Main Methods:

• Retrospective analysis of 51 epilepsy patients undergoing stereoelectroencephalography (SEEG).
• Data collected at 1, 3, 6, and 12 months post-implantation.
• Responder status defined as ≥50% seizure frequency reduction.

Main Results:

• Responder rates varied: 71.4% at 1 month, decreasing to 33.3% at 6 months, and rising to 50% at 12 months.
• Complete seizure freedom observed in up to 42.9% at 1 month.
• No significant associations found with age, sex, imaging, stimulation, electrode count, or medication type/load.

Conclusions:

• Lack of predictive variables suggests microlesions from electrodes may transiently disrupt epileptogenic networks.
• Electrode location might be more critical than quantity.
• Further prospective studies are needed to elucidate the mechanisms and role of antiseizure medications.