Abstracts

Rationale: Background: Intracarotid amobarbital procedure (IAP) is considered the gold standard for language lateralization. EEG changes during IAP are well defined, but how these EEG changes correlate with IAP interpretation and neurobehavioral findings are not defined. This study correlated the EEG findings with the clinical and neuropsychological test results (language score and memory testing) in children who underwent IAP for refractory epilepsy. Methods: Method: Fifty consecutive children who underwent IAP test at Texas Children s Hospital between 2004-2009 were retrospectively reviewed. Injection was first administered to the carotid artery ipsilateral to the pathological hemisphere. IAP was considered conclusive (CON) for language lateralization if aphasia or paraphasia occurred and inconclusive (INCON) if IAP was aborted due to agitation and/or obtundation. Digital trending analysis was used to quantify EEG findings in the 43 available EEGs. Results: Results: Mean age was 13.5 2.8 (range: 8-18 years). Thirty-five were right handed and 10 left (L) handed. The seizure focus was on the left in 32 and on the right in 12. Average full scale IQ was 88 (range 52 to 119). Amobarbital dose ranged from 60 to 150 mg (mean: 107 19.9); additional amobarbital was required in 23. Angiography showed no contralateral cross-filling and no seizures occurred during the IAP. EEG changes occurred within 10 seconds following injection, becoming maximum between 60-90 seconds. Ipsilateral EEG changes occurred in 34; early onset bilateral (BL) changes within 30 seconds in 10; a fast rhythm occurred in only 9. Although contralateral arm weakness occurred in all, sustained EEG changes did not occur in 11. Clinically, 34 children developed aphasia with ipsilateral injection; bilateral language representation was suspected in 2; no aphasia occurred in 3; IAP was INCON in 7. The ICON group had a lower mean age versus the CON group (10.8 3.0 vs 14 2.5 years) (p: 0.006). Although the INCON group had a lower amobarbital dose, EEG showed higher amplitude, sustained ipsilateral slowing with L sided injection at 30 seconds (133 119 vs 119 51uV) (p: 0.014). BL EEG changes occurred more often in the INCON compared to the CON group (57% vs 17%, p: 0.043). Conclusions: Conclusion: Ipsilateral EEG changes are associated with language lateralization with CON IAP results. Younger ages and bilateral EEG slowing are predictors for INCON IAP results. The IAP may be CON even when contralateral arm weakness occurs with only minimal EEG changes.