Abstracts

Rationale: Decline in verbal memory is frequently observed after left anterior temporal lobectomy (ATL). Right ATL is only rarely associated with mild memory problems and detailed neuropsychological evaluations usually fail to consistently reveal the presence of deficits in other cognitive domains after right ATL. There is evidence that some patients with frontotemporal dementia (FTD) who have lobar atrophy of the left temporal lobe developed into visual artists, but it remains unclear if these new skills are related to a release of inhibition of the right hemisphere or a compensatory strategy. In addition, in these demented patients the involvement of other neural structures in the degenerative process prevents the assessment of the specific role of the temporal lobe atrophy. Thus, in this study, we compared the performance of patients after right and left temporal lobectomy on tests that measure verbal and figural creative innovation. Methods: Eighteen subjects, 9 with right and 9 with left ATL, performed the verbal and figural forms of the Torrence Test of Creative Thinking. The verbal and figural creativity scores were compared between and within the two groups.Results: Creativity scores were not different between the two groups. In the left ATL group, figural scores were not different than verbal scores. In the right ATL group, however, figural scores were significantly higher than verbal scores (P = 0.028).Conclusions: The finding that patients with left ATL,when compared to those with right ATL, did not have enhanced figural creativity fails to support the left temporal lobe disinhibition postulate of enhanced figural creativity that was based on observations of patients with FTD. In contrast, patients with right ATL performed better at creative figural tasks than verbal tasks, while patients with left ATL had similar performances on both tasks. The current study, unfortunately, could not determine if the superior figural versus verbal creativity found in the right ATL group is induced by the surgery or is related to presence of chronic right temporal lobe epilepsy. Patients with left temporal lobe epilepsy sometimes exhibit hypergraphia. It is possible that patients with right temporal lobe epilepsy may exhibit a parallel phenomenon of increased drawing fluency, a quality that might account for the high artistic performance on visual arts in some patients with epilepsy. Future studies should compare performance of the same patients prior and after ATL to distinguish if the figural versus verbal creativity dissociation is due to the surgery or the chronic epilepsy.