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Bilateral medial temporal lobe damage without amnesic syndrome: a case report
1Center for Neuroscience, University of California at Davis, USA.
Abstract:
After the case report H.M. [42], unilateral neurosurgical interventions in the mediotemporal area have no longer been performed, if damage to the contralateral mediotemporal region was present, because of running the risk of provoking a postoperative amnesic syndrome. We present a patient with bilateral mediotemporal cysts and medically refractory complex partial seizures originating in the left mediotemporal region. Although our patient had additional right mediotemporal damage and poor non-verbal learning and memory, the left amygdaloid body and the left hippocampal formation were resected because the patient passed a selective anterior temporal lobe Amobarbital test. Postoperatively, our patient's non-verbal memory recovered to normal, but his verbal memory declined. Nevertheless, he was non-amnesic and seizure-free.
Insights
This study reports a patient with bilateral mediotemporal cysts who underwent successful epilepsy surgery. Despite pre-existing memory deficits, the patient achieved seizure freedom with improved non-verbal memory.
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.