Abstracts

Rationale: Psychomotor and cognitive slowing are known complications of chronic epilepsy. In this investigation we systematically compared the speed and efficiency of epilepsy and control groups across increasingly complex psychomotor tasks in order to determine the impact of task difficulty on motor/psychomotor slowing. A secondary aim was to characterize the "motor age" of epilepsy patients and its relative discrepancy compared to chronological age. Methods: Patients with chronic temporal lobe epilepsy (TLE)(n=74) and healthy controls (n=69), mean age 36.5 and 39.1, were administered three 25-item psychomotor tasks of increasing complexity. Task complexity ranged from “simple” (round peg in round hole), “intermediate” (slotted key in grooved pegboard), to “complex” (assembly of three items with placement in pegboard). The dependent variables of interest were: a) mean time to task completion, b) mean time per unit item (25 divided by total time to completion), and c) "motor age", that is, the predicted age of epilepsy patients based on their performance time, using the results of regression of age and gender to completion time in controls. Results: Data were analyzed by 2x3 repeated measures ANOVA. Increasing task complexity was associated with significantly (p <.001) slower performance across subject groups (task effect). Epilepsy patients performed significantly (p <.001) worse than controls across all tasks (group effect). Significant (p <.001) progressive slowing was observed in the TLE group compared to controls aas a function of increasing psychomotor complexity (group x task interaction). Finally, epilepsy patients exhibited increasingly abnormal “motor age” across tasks characterized by increased disparity between predicted compared to actual chronological age. Conclusions: Psychomotor speed and efficiency is not only impaired in chronic TLE patients compared to controls, but it is differentially affected by task complexity with increasingly slowed and inefficient performance in conjunction with increasing task difficulty. Based on identified relationships between chronological age and motor performance in controls, the “motor age” of epilepsy patients is significantly advanced compared to chronological age.