Abstracts

For many years the intracarotid amobarbital procedure (IAP) or Wada test has been used to clarify and establish hemispheric language dominance in preparation for epilepsy surgery. However, since the IAP is an invasive procedure, finding an alternative means of obtaining this information is desirable. More recently MSI has shown promise as a noninvasive procedure to establish language dominance. However, studies of the relationship between IAP results and MSI findings are few to date, and this is particularly true with the pediatric population. This study reports preliminary data comparing these procedures. A retrospective chart review was conducted of pediatric patients with intractable seizures from the Minnesota Epilepsy Group who had both IAP and MSI language activation studies since 1998. The IAP was conducted at the Minnesota Epilepsy Group and the MSI study was done either at the Minnesota Epilepsy Group or the University of Texas Houston Health Science Center using established protocols. Five patients (three males and two females) were studied in the initial comparison. Ages ranged from 6-17 years. Four of the five subjects had the two procedures within 8 months of each other. The fifth subject had the MSI study 4.5 years post-IAP. The IAP and MSI concordance rate was 80% (4 of 5) with three subjects classified with left language dominance on both IAP and MSI, and one subject classified bilateral for language on both IAP and MSI. The one remaining case was a 16-year-old male who was left hemisphere dominant on MSI and bilateral for language on IAP. He had both procedures within a three-month period. These very preliminary data suggest language dominance agreement between MSI and IAP in 80% of the cases. However, the very small N does not yield the necessary evidence for reliable clinical decision-making solely based on MSI findings. A higher level of concordance is desirable for the MSI to replace the IAP. Additional data will help determine whether the MSI and IAP findings are consistently correlated in pediatric populations and whether the less invasive MSI can eventually replace the IAP to establish language dominance in preparation for epilepsy surgery.