Abstracts

RATIONALE: Ambiguous IAPs or IAPs that are inconsistent with MRI, EEG or SPECT are not uncommon. Most studies have compared IAP and Neuropsychological Testing (NPT) with MRI, EEG, and SPECT using the "gold standard" of success following surgery to localize lesions. We compared NPT in patients who had IAPs that were consistent with other localizing procedures (OLP) with NPT in patients with IAP's that were ambiguous, uninformative, or inconsistent with OLPs. We included patients less likely to go for surgery to determine whether NPT results differ in patients with consistent evidence of a focal lesion vs. patients with discrepant findings. METHODS: 21 patients had both NPT and IAP. Results of MRI (n=20), video EEG (n=20), routine EEG (n=8), and SPECT (n=9) were rated for right hemisphere (RHD), left hemisphere (LHD), bilateral (BD), or no dysfunction (ND). The NPT battery included the WAIS-R, Logical Memory and Visual Reproduction from the WMS-R, Finger Tapping, Trail Making Test, a word list task, and one other nonverbal memory test. NPT was rated for RHD, LHD, BD, or ND. IAP's were rated as showing RHD or LHD when there was a difference of ? 2 between injections. RESULTS: Our sample was 47.6% female with a mean age of 37.9, mean education of 13, and mean Verbal, Performance and Full Scale IQ's of 91, 97, and 93. Ten had consistent evidence of RHD, 3 had consistent evidence of LHD, and 8 had discrepancies between IAP and OLP. The 3 patients with IAP and OLP suggesting LHD had NPT consistent with LHD. Of the 10 with IAP and OLP suggesting RHD, NPT suggested RHD in 30%, was uninformative in 60%, and suggested LHD in 10%. In patients with uninformative IAP's, 47% had uninformative NPT, 42% had NPT that was consistent with OLP, and 10% had results that were in conflict with OLP. CONCLUSIONS: NPT was most consistent with IAP, MRI, EEG, and SPECT in patients with focal LHD. In patients with IAP and OLP suggesting focal RHD, NPT was most likely to be uninformative, but was rarely inconsistent in lateralizing a lesion compared to OLP. Patients with uniformative IAPs may be equally likely to have uninformative NPT or NPT results that are consistent with OLP; NPTs, in this group, were not more likely to be discrepant with OLP.