Abstract

Across different studies, patients with temporal lobe epilepsy (TLE) demonstrate
impairments on numerous measures of attentional control that are classically associated
with frontal lobe functioning. One aspect of attentional control that has not been
examined in TLE is the ability to execute two modality-specific tasks concurrently. We sought to examine the status of dual-task coordination in TLE. We further examined the cohorts’ performance on a range of traditional measures of attentional control. Eighteen
TLE patients and 22 healthy controls participated in the study. Dual-task performance
involved comparing the capacity to execute a tracking and a digit recall task simultaneously with the capacity to execute the tasks separately. We also administered measures of: set
shifting (odd-man-out test), sustained attention (elevator counting), selective attention
(elevator counting with distraction), and divided attention (trail making test). We found that the proportional decrement in dual-task performance relative to single-task performance did not vary between the groups (TLE = 92.48%; controls = 93.70%), nor
was there a significant difference in sustained attention (p > .10). Patients with TLE did demonstrate marked deficits in selective attention (p < .0001), divided attention
(p < .01), and set shifting (p < .01). These findings add to the knowledge about cognitive
dysfunction in TLE, indicating that impairments in attentional control in TLE tend to be
selective. The greatest deficits appear to be on tasks that invoke a high level of processing resources. In contrast, sustained attention is less compromised and the capacity to allocate cognitive resources appears to be normal in patients with TLE.