AGE AT ONSET AND NEUROPSYCHOLOGICAL FUNCTION IN FRONTAL-LOBE EPILEPSY

Purpose: Previous studies into the cognitive consequences of frontal l obe epileptic dysfunction may have proved inconclusive, due to a facto r not commonly accounted for: Damage or disturbance during different e pochs of development may give rise to different levels of neuropsychol ogical dysfunction. In this study, we investigated the influence of ag e at onset on cognitive performance in a group of subjects with fronta l lobe epilepsy (FLE). Methods: Seventy-four subjects (42 with left, a nd 32 with right) FLE were classified into early (0-6 years), intermed iate (7-11 years) or late onset (greater than or equal to 12 years) an d their performance recorded on a battery of measures assessing both e xecutive and motor skills. Results: On the measures of executive funct ioning, no consistent pattern emerged, whereas on the measures of moto r skill, the results suggested that a right-sided early onset (i.e., 0 -6 years) did not impair performance compared to a later lesion within the same hemisphere. Furthermore, this sparing of performance was not observed within the left hemisphere. Conclusions: Overall, the result s suggest that individuals with differing ages of epilepsy onset will be differentially impaired on certain cognitive tasks. Several tentati ve ramifications of these results are suggested.