Abstracts

Rationale: Modality specific cognitive morbidity has been documented following anterior temporal lobectomy (ATL) for the treatment of intractable temporal lobe epilepsy (TLE) with worsening of language skills and verbal memory following resection of dominant structures and worsening of visual memory following non-dominant resections. In recent years, laser ablation surgery has emerged as a minimally invasive alternative that targets mesio-temporal structures sparing temporal neocortex, however limited data is available regarding cognitive outcome following this procedure. We present outcome data for 10 patients with pre and post-surgical neuropsychological evaluations in order to assess the impact of this novel procedure on cognitive status.Methods: Out of 17 cases that have undergone laser ablation surgery in our institution, 10 subjects (5 males; 5 famles) completed pre- and post-surgical neuropsychological testing. All subjects were left hemisphere dominant as determined by functional MRI and/or WADA. Subjects had a mean age of 42 years (range 22-62). Four subjects underwent left-sided and 6 right sided ablations. Average number of months between the procedure and the post-surgical testing was 6.6 months (range 5-10).Results: Of the 4 subjects that underwent ablation of dominant structures, 3 showed a deterioration in measures of verbal memory ranging from 0.5 to 1 standard deviation below pre-surgical scores. Their performance on all language and non-verbal variables either remained unchaged or improved post-surgically. Test scores (including visual memory) for all subjects with non-dominant ablations either remained stable or improved on follow-up testing.Conclusions: Early follow-up outcome data indicates that ablation of dominant mesio-temporal structures may result in additional verbal memory morbidity but does not negatively impact language functions including confrontation naming and verbal fluency as it has been documented in ATL. Non-dominant ablations appear to have a positive impact in overall cognition likely the result of improved seizure control.