31 Item and Associative Visual Memory in Presurgical Temporal Lobe Epilepsy Patients

Abstract

Objective:

Patients with temporal lobe epilepsy (TLE) commonly show memory deficits on neuropsychological tests. The BVMT-R is a widely used test of visual learning and memory that involves accurately reproducing an array of figures in the correct special location. The present study examined performance processes of visual memory in presurgical patients with TLE, including item (i.e., accuracy) and associative memory (i.e., location), which have been shown to be dissociable in studies of visual memory in other neurologic populations.

Participants and Methods:

Participants included nine patients with left TLE (67% female; 67% left-handed; mean age = 46.15 years, range = 24-55; mean education = 14.8 years, range = 9-18) and six patients with right TLE (17% female; 33% left-handed; mean age = 57.64 years, range = 22-62; mean education = 15.52 years, range 11-18). Mean duration of epilepsy was 19 years. Participants had an average of two failed anti-seizure medications prior to surgery. TLE groups were compared to 22 healthy controls (36% female; 14% left-handed; mean age = 33.68 years, range = 2253; mean education = 17.66 years, range = 1620). All participants completed comprehensive neuropsychological testing at a large Northeastern medical center. The BVMT-R was scored using standard and novel scoring paradigms. All data were retrospectively reviewed from archival datasets.

Results:

MANCOVA results indicated a significant multivariate main effect for group membership and standard BVMT-R scoring after controlling for level of education, Wilks’ A = 0.59, F(4, 64) = 4.91, p = .002. The multivariate partial eta squared (np2) of .58 indicated a strong relationship between group membership and both immediate and delayed recall, with the control group performing better overall. The TLE groups did not perform significantly different from each other. A significant multivariate main effect for group and novel BVMT-R scoring was found (also controlling for education), Wilks’ A = 0.42, F(8, 58) = 3.97, p = .001. Overall, the control group demonstrated better item learning with no significant difference between TLE groups observed. Both the control (M = (16.5, SD = 2.04) and left TLE (M = 12.33, SD = 4.03) showed stronger associative learning compared to the right TLE group (M = 10.2, SD = 4.27). For item and location delayed recall, controls (M = 4.82, SD = 1.62) had more accurate recall compared to left TLE (M = 1.56, SD = 2.04) with a trend toward better performance compared to the right TLE patients (M = 2.6, SD = 1.82); the TLE groups performed similarly. No difference was observed for associative delayed recall between the three groups.

Conclusions:

Patients with right TLE showed worse associative learning compared to left TLE, while performance was generally comparable to their right TLE counterparts on other novel BVMT-R scoring paradigms. Unsurprisingly, patients with TLE performed worse on BVMT-R using standard scoring procedures, though no lateralizing effect was observed. While these findings suggest that associative visual learning weakness may be characteristic of right TLE, findings should be interpreted cautiously the given small sample size and demographic considerations (i.e., uneven gender distribution, lack of data on ethnicity/race).