Abstracts

Rationale: The role of a lesion in cognitive dysfunction in mesial temporal sclerosis(MTS) is well established. It is less clear if abnormal electrical activity can also impact on cognitive functioning. We evaluated the impact of contralateral electrographic activity on cognitive functioning in patients with unilateral MTS. Methods: We included all cases of unilateral MTS that underwent video-EEG monitoring and neuropsychological testing in our service between Jan1999 and Mar2008. Exclusion criteria were <6 years of education, IQ <70, ages <16 or >55, uncompensated psychiatric disease, additional MRI lesions and extratemporal ictal or interictal epileptiform activity. According to lesion side (left or right) and presence of unilateral or bilateral ictal and interictal epileptiform activity, patients were classified as: unilateral right(UR), bilateral right(BR), unilateral left(UL) and bilateral left(BL). A group of normal individuals matched for age, gender and education served as a control group. Comparisons among groups were performed with SPSS version 13.0, with nonparametric Kruskal-Wallis and Mann-Whitney, with a significance level of 0.05. Results: Of 104 patients with uMTS, 31 were excluded(11 had <6 years of education, 11 for age, 3 for psychiatric disease and 4 for IQ less than 70). The study group consisted of 73 patients and 26 controls. Patients were classified as: UR(22), BR(10), UL(35) and BL(6). Groups did not differ in relation to gender, age(mean 35.9 yrs), education(mean 11.4 yrs), and seizure frequency at the time of neuropsychological testing. Patients groups had significantly lower FSIQ and VIQ than controls(FSIQ: C=103.9, UR=94.3, BR=89.9, UL=93.5, BL=91.7, p=0,017). Patients with LMTS performed significantly worse than RMTS patients and controls in longterm recall of verbal material (RAVLT 6, 7 and 7 days: C=5.5, UR=5.5, BR=6.4, UL=3.5, BL=1.0, p<0,0001), BL attaining the lowest scores. BR and BL had higher scores of memory complaints than UR and UL, respectively(C=33.8, UR=27.3, BR=36.7, UL=41.8, BL=58.0, p=0,017). Verbal fluency(FAS) was equally impaired in all groups(C=37.8, UR=29.3, BR=29.4, UL=28.8, BL=29.0, p=0,004). BR, BL and UL scored significantly worse in confrontation naming than UR and C(C=45.0, UR=42.3, BR=36.9, UL=37.5, BL=38.4, p=0,017). Bilateral left and right groups scored higher than their unilateral counterparts in the Hamilton Anxiety(C=5.0, UR=6.1, BR=7.3, UL=7.8, BL=9.6, p=0,027) and Depression Scales(C=3.8, UR=5.1, BR=6.6, UL=7.4, BL=9.4, p=0,003). Conclusions: Bilateral functional involvement in unilateral MTS impacts negatively on cognition. Left-sided lesions affect verbal episodic memory; bilateral involvement in left MTS causes more profound verbal memory impairment. Contralateral involvement in right MTS affects language function. Left sided lesions are associated with higher anxiety and depression scores. Bilateral dysfunction is associated with higher anxiety and depression scores than unilateral dysfunction. FAPESP Process 05/56464-9 (Cinapce)