Is impairment in set-shifting specific to frontal-lobe dysfunction? Evidence from patients with frontal-lobe or...

Frontal-lobe epilepsy (FLE), temporal-lobe epilepsy (TLE), and matched-control subjects were administered the Trail Making Test (TMT) of the Delis-Kaplan Executive Function System (D-KEFS; Delis et al., 2001), which assesses set-shifting on a visuomotor sequencing task. Results indicated that patients with FLE were impaired in both speed and accuracy on the switching condition relative to patients with TLE and controls. The two patient groups did not differ from controls on the four baseline conditions of the test, which assess visual scanning, motor speed, number sequencing, and letter sequencing. In addition, seizure-related variables (i.e., age of seizure onset, duration of epilepsy, and seizure frequency) failed to correlate with set-shifting performance in patients with FLE. These results suggest that patients with FLE can be reliably distinguished from those with TLE and control subjects on set-shifting as measured by the DKEFS TMT.