Bilateral medial temporal lobe damage without amnesic syndrome: a case report

Area of Science:

• Neurology
• Neurosurgery
• Epileptology

Background:

• Unilateral mediotemporal resections are typically avoided with contralateral damage due to amnesia risk, following the H.M. case.
• Medically refractory epilepsy with bilateral mediotemporal lesions presents a surgical challenge.
• Selective anterior temporal lobe Amobarbital testing aids in predicting memory outcomes.

Observation:

• A patient presented with bilateral mediotemporal cysts and complex partial seizures originating from the left mediotemporal region.
• The patient had pre-existing deficits in non-verbal learning and memory due to additional right mediotemporal damage.
• Despite these factors, a left amygdaloid body and hippocampal formation resection was performed after a positive Amytal test.

Findings:

• Postoperatively, the patient's non-verbal memory function improved significantly.
• Verbal memory function experienced a decline after the surgery.
• The patient became seizure-free and did not develop a postoperative amnesic syndrome.

Implications:

• This case challenges the strict contraindication for mediotemporal surgery in patients with bilateral lesions.
• Selective Amytal testing can be a valuable tool in identifying suitable candidates for epilepsy surgery.
• Careful patient selection and surgical planning can lead to successful seizure control with manageable memory outcomes.