A revised intracarotid etomidate memory (Wada) procedure

Area of Science:

• Neuroscience
• Neurosurgery
• Epileptology

Background:

• Assessing unilateral memory function is crucial for epilepsy surgery planning.
• Standard anterior temporal lobectomy requires understanding hemispheric memory contributions.
• The original etomidate speech and memory (e-SAM) procedure had significant side effects.

Purpose of the Study:

• To evaluate unilateral memory function using a modified e-SAM procedure.
• To assess memory lateralization in epilepsy patients undergoing temporal lobectomy evaluation.
• To refine the e-SAM procedure for improved patient safety and clinical utility.

Main Methods:

• A modified etomidate speech and memory (e-SAM) procedure involving single bolus injection was developed.
• Unilateral memory testing was performed via intracarotid injection of etomidate in 21 epilepsy patients.
• Neuropsychological data were analyzed to compare memory performance between ipsilateral and contralateral injections.

Main Results:

• Significant differences in memory scores were observed between ipsilateral and contralateral injections relative to the epileptogenic focus (P < 0.01).
• The modified bolus injection technique eliminated major side effects in 18 subsequent patients.
• Results suggest the procedure effectively reflects unilateral hippocampal memory function and dysfunction.

Conclusions:

• The modified etomidate procedure successfully demonstrates the memory function of the epileptogenic hemisphere.
• The technical revision from continuous to bolus injection is effective and safe.
• This revised procedure provides essential clinical data for surgical decision-making in epilepsy patients.