Neuropsychological aspects of frontal lobe epilepsy

This study sought to increase our understanding of the neuropsychological consequences of frontal lobe epilepsy and surgery for this condition. In so doing, some suggestions were made on the role of the frontal lobes, and ways of assessing possible dysfunction in this area. The performance of a large group of subjects with clearly defined frontal lobe epilepsy (n=74), was examined on a comprehensive battery of neuropsychological measures. The performance of this group was compared to a control group of subjects with clearly defined temporal lobe epilepsy (n=57). There were few consistent group differences in test performance. Neither were there any strong relationships between test scores and epilepsy related variables. The frontal lobe group was sub-divided into more discrete regions (dorsolateral, orbital, mesial, motor/premotor, and extensive), and the neuropsychological characteristics associated with dysfunction in these regions was assessed. Although differences between the samples were small, some of the neuropsychological deficits previously associated with these regions were observed. Since a number of measures were used, their validity in assessment of frontal lobe dysfunction was assessed. A composite score of frontal lobe dysfunction was also derived using multivariate analysis. Comparisons revealed that the new composite score can be considered a more sensitive measure in the assessment of frontal lobe epilepsy, than any individual neuropsychological measure investigated. In addition to the group study, four cases were followed up before and at regular intervals after surgery. The results highlighted a number of significant findings, from both a clinical and theoretical perspective. Although the results of the comparisons between frontal and temporal lobe groups, and between different frontal regions. revealed some significant functional differences, these were not consistently demonstrated. The results suggest the necessity to regard these groups collectively, since epileptic activity in any one specific region can cause deficits associated with other areas.