Verbal Memory Localized in Non-language-dominant Hemisphere: Atypical Lateralization Revealed by Material-specific...

Area of Science:

• Neuroscience
• Epileptology
• Neurosurgery

Background:

• Hippocampectomy is a treatment for mesial temporal lobe epilepsy (MTLE) with hippocampal sclerosis.
• Patients with MTLE without hippocampal sclerosis or with preserved memory function face higher risks from hippocampectomy.
• Standard understanding posits verbal memory and language functions lateralize to the same hemisphere.

Observation:

• A case study of a 24-year-old male with drug-resistant MTLE without hippocampal sclerosis is presented.
• The patient exhibited preserved verbal intelligence quotient and memory, indicating high risk for memory decline post-surgery.
• A super-selective Wada test was performed to assess memory and language lateralization.

Findings:

• The super-selective Wada test revealed right-sided dominance for both verbal and visual memory.
• Language function was left-dominant, deviating from the typical hemispheric co-localization.
• Following hippocampectomy, the patient achieved seizure freedom with no memory decline at one year.

Implications:

• This case highlights that memory and language dominant hemispheres may not align in epilepsy patients with atypical profiles.
• Detailed functional lateralization assessments are crucial for personalized treatment strategies in drug-resistant epilepsy.
• Super-selective Wada testing offers valuable insights for surgical planning in complex epilepsy cases.