Abstracts

Rationale: Because of neurodevelopmental aspects, age at cognitive assessment is an important issue when studying children with TLE.Some authors argue that early onset TLE is associated with greater than expected effects on brain structure and cognition,suggesting that,rather than benefiting from increased plasticity with reorganization and protection of cognitive function, presence of recurrent seizures in the developing may be associated with an adverse effect on brain structure and function.We aimed to compare the performance of children with TLE with early versus late age of seizure onset in executive functions (EF). Methods: 35 patients(11.7±2.1 ys;IQ 97.7±11.6)and 25 controls(12.1±2.4 ys;IQ 109.4±14.3)were evaluated with a neuropsychological battery made by 8 tests for EF.Neurodevelopmental aspects of EF were analyzed with ANCOVA, using IQ as a covariate, in 3 analyses:1.Patients’ age at cognitive assessment (younger than 12 versus older than 12 years);2.Patients were compared to age-matched controls according to their age (younger and older) and;3.Early (< 4 years-old) versus late (≥ 4 years old) seizure onset.The impact of seizure freedom in EF was analyzed with analysis of co-variance (ANCOVA), using IQ as a covariate, comparing performances of patients either with or without seizure control. Results: 1. Younger patients with TLE showed worse performances in Digit Forward (F:8.30;p:0.007) and Backforward (F:25.01; p:0.001), MFFT (number of errors-F:4.74;p:0.037), TM(part A-F:5.16;p:0.030 and part B-F:9.82;p:0.004),Word Fluency (animals-F:11.83;p:0.001 and foods - F:13.33;p:0.001) and Finger Windows(F:13.63;p:0.001);2.Compared to age-matched controls,younger patients with TLE showed worse performance in Digit Forward (F:6.90;p:0.020) and Number and Letter (F:6.76;p:0.020). Older patients showed worse performance in TM (part B number of errors -F:4.24; p:0.050) and WCST (categories achieved - F:5.95;p:0.020). 3.Children with early age of onset of epilepsy had a higher occurrence of impairment compared to children with late age of onset in Digit Forward (F:22.11;p:0.001) and Backforward (F:16.55;p:0.001),MFFT(number of errors - F:5.67;p:0.024),TM(part B-F:15.20;p:0.001),Word Fluency (animals-F:7.50;p:0.010 and foods-F:7.71;p:0.009),Finger Windows(F:16.87;p:0.001)and Number and Letter(F:5.75;p:0.022).Seizure-free patients had a better performance than non seizure-free patients in WCST failure to maintain set (F:6.99; p:0.013), but not in other tests. Conclusions: Younger children, patients and controls, had a worse performance than older children, as expected. Earlier seizure onset, but not seizure control, had a relevant impact on a large set of paradigms used to evaluate EF. Therefore, corroborating our previous findings,age of onset seems to be more important than epilepsy severity regarding EF. This early developmental impact on brain structure and function may be related to a higher risk of further adverse cognitive outcomes in longstanding and intractable TLE. Supported by:CNPQ;CAPES;FAPESP