Abstracts

Rationale: The Rey Complex Figure Test (RCFT) is frequently included in epilepsy pre-surgical neuropsychological test batteries as a measure of figural memory. Although reasons currently remain unclear, research suggests that RCFT recall is more closely associated with left temporal lobe function than right in epilepsy patients.In our center, a tendency for left temporal lobe epileptics (LTLE) to omit major features on the right side of the design was repeatedly observed. The purpose of the current study was to evaluate whether this aspect of RCFT recall is more likely to be present in LTLE than in right temporal lobe epilepsy patients (RTLE). Methods: 42 candidates for temporal lobe resection for intractable epilepsy(20 left,18 right,4 bilateral)were administered the RCFT as part of the pre-surgical neuropsychological work-up. Recall was tested immediately after copy (IR)and following 30 minute delay (DR). Figures were scored utilizing the Meyers & Meyers (1995) system. Of specific interest was the right most aspect of the figure (See Figure 1). Patients completely omitting these features on either IR or DR (see Figure 2) were assigned to the Right Omission(RO. Those who included any aspect of these scoring units on both IR and DR conditions were assigned to No Omission (NO). Those with evidence of bilateral seizure activity were grouped with the LTLE patients for analysis given the evidence of left hemisphere dysfunction. Results: 46% of LTLE/Bilateral patients(11/24) met criteria for the RO group, compared to 11% of RTLE patients(2/18). This difference was highly significant (Chi-Square = 6.095, p.< .014). With regard to other neuropsychological tests, the RO group performed more poorly on both immediate (T = -2.75, p< .009) and delayed recall (T = -2.45, p<.019) conditions of the WMS-R Logical Memory, but not on any other measure. Conclusions: Almost one-half of patients with left temporal dysfunction omitted the right most aspect of the design in recall of the RCFT. The high proportion of LTLE patients omitting this sizeable aspect of the design (22% of the figures possible scoring points)may help explain research suggesting greater sensitivity of the RCFT to left as opposed to right sided seizure onset. Omission of the right was also associated with poor performance on a prose passage recall task, a test considered sensitive to left temporal lobe dysfunction. The groups did not differ on any other measure making it unlikely that right omission is simply an indication of diffuse cognitive impairment. To the extent that the left temporal lobe mediates representation of right-sided space, the incidence of right omission on the RCFT should increase following left temporal lobectomy. While infrequent in the current sample, the presence of right-sided omission in RTLE patients could indicate left temporal dysfunction and may suggest a heightened risk of significant memory problems post surgery.The relationship between these findings and post-surgical memory functioning warrants investigation.