Abstracts

Whether chronic temporal lobe epilepsy (TLE) is associated with progressive adverse changes in brain structure, cognitive function, or psychiatric status remains controversial. Much of the available evidence is cross-sectional in nature, focusing on limited areas of outcome, with few modern prospective studies. This 4-year prospective investigation assesses changes in brain structure, cognitive function, and psychiatric status in patients with chronic TLE compared to healthy controls. An overall cohort of 160 patients with TLE and healthy controls are returning for examination four years after their baseline assessment. This report reviews the prospective outcomes for a consecutive series of 28 TLE and 21 healthy controls. All subjects underwent quantitative MRI volumetrics (total volumes of gray matter, white matter and CSF), neuropsychological status (assessment of intelligence, language, perception, memory, executive function, motor ability), and standardized psychiatric interview (SCID). Analyses included examination of group by time interactions and the proportion of TLE subjects exhibiting adverse outcomes (i.e., change exceeding 2 standard deviations of the healthy controls). [italic]Cognition[/italic]. Significant group by time interactions (p [lt] 0.05) were obtained for measures of intelligence, memory, executive function, and mental/motor speed. Post-hoc analyses indicated that these significant interaction effects were due to either lack of test-retest gain (practice effects) in TLE subjects compared to controls, frank cognitive decline in TLE subjects, or a combination of these effects. A subset of approximatly 20% of TLE subjects showed adverse cognitive outcomes. [italic]Quantitative MRI[/italic]. There were no significant group by time interactions for the volumetric measures, but a trend of reduced overall gray matter and increased CSF was seen in the TLE subjects. [italic]Psychiatric status[/italic]. Significant differences were evident between groups. Interval Axis I disorders were reported by 69% of TLE compared to 39% of controls (p [lt] .05), with mood disorders evident in 50% of TLE and 21% of controls (p [lt] .05). Adverse effects of chronic TLE were identified in this prospective investigation. Most burdensome was ongoing interictal psychiatric co-morbidity, characterized predominantly by mood disorders, and differences in cognitive trajectories over the test-retest interval. Evident trends in quantitative MR volumetrics suggested greater decreases in gray matter and increased CSF in TLE subjects compared to controls. Analyses of individual subject data suggests that a sizeable minority of subjects are at increased risk of adverse outcomes in the context of ongoing chronic TLE. (Supported by NIH NS 2RO1-37738 and M01 RR03186 (GCRC).)