Does the intracarotid amobarbital procedure predict global amnesia after temporal lobectomy?

PURPOSE: The intracarotid amobarbital procedure (IAP) is widely used to help predict who might be at risk for postoperative amnesia after unilateral temporal lobectomy for intractable seizures. We describe the memory outcome in 10 patients who underwent standard temporal lobectomy, including mesial temporal structures, despite failing the memory portion of the IAP after injections both ipsilateral and contralateral to the resected seizure focus. METHODS: Data for seven of the study subjects were obtained through a retrospective review of patients assessed on a surgical epilepsy unit during a 15-year period who failed the Montreal Neurological Institute IAP memory protocol after both ipsilateral and contralateral injections and subsequently underwent unilateral temporal lobectomy. More recently, we have studied temporal lobectomy patients who failed the Medical College of Georgia memory protocol after both ipsilateral and contralateral injections (n = 3). Preoperative and postoperative memory test scores were compared, and data regarding seizure outcome and self-perception of postoperative memory were collected. RESULTS: At follow-up, none of the patients presented with a pattern indicative of a global amnesia, and 80% demonstrated >90% improvement in their seizure disorder or were seizure-free. CONCLUSIONS: These findings indicate that bilateral memory failure on the IAP does not preclude the removal of an epileptogenic temporal lobe or a successful surgical outcome. In addition, the findings raise questions regarding the validity of the IAP and the possibility that memory may be reorganized in patients with a long history of temporal lobe epilepsy.

Neuropsychological assessment for temporal lobe epilepsy surgery.

Neuropsychological assessment consists of a comprehensive evaluation of cognitive functioning and most often some evaluation of motor skills and sensory status also. Cognitive functions sampled typically include "intelligence" (IQ tests), attention, language skills, visuospatial abilities, "executive skills" and other abilities associated with frontal-lobe function, and learning and memory. Thus, the assessment samples vary widely among a variety of functions, providing a comprehensive picture of an individual's strengths and weaknesses. The resulting pattern points to the probable site of epileptic focus. Neuropsychological findings also serve to predict the risk for postsurgical cognitive decline and, when performance before and after operation is compared, they provide data on the impact of surgery upon cognitive functioning. Comprehensive evaluation of learning and memory is particularly important in this context, because of the frequency of temporal lobe epilepsy and the prominence of memory dysfunction associated with it. In addition, patients slated for elective surgery may also undergo an intracarotid amobarbital procedure (IAP), which is performed to determine the side of cerebral dominance for language and to test the memory capabilities of each hemisphere alone. All of these specialized neuropsychological tools are discussed in this paper.

Influence of seizure content on interpreting psychopathology on the MMPI-2 in patients with epilepsy.

We investigated whether seizure content items inflate MMPI-2 scores in persons with epilepsy. A mean MMPI-2 profile was generated for 100 epilepsy patients. Two expert raters then identified MMPI-2 items reflecting seizure symptoms. When individual profiles were rescored to remove elevations caused by seizure content, some statistically significant (but not clinically significant) decreases were observed. The MMPI-2 appears to be a valid assessment instrument in epilepsy. In most cases seizure content did not alter clinical interpretation. When the interest is in detecting symptom change, assessing both statistical and clinical significance is recommended in future MMPI-2 research.

Principal identifying features of the syndrome of nonverbal learning disabilities in children.

The identifying features of the syndrome of nonverbal learning disabilities (NLD) were examined with a view to determining their relative discriminant validity. A stepwise linear discriminant function analysis of children with NLD (n = 29), children with reading and spelling disabilities (Group R-S; n = 27), and a group of nonclinical children (NC; n = 27) on 15 neuropsychological variables yielded a subset of scores on four tests (Target Test; Trail Making Test, Part B; Tactual Performance Test; and Grooved Pegboard Test) that accurately (> 95%) discriminated the NLD group from the R-S and NC subjects. Of the neuropsychological features of NLD described by Rourke (1987, 1988b, 1989), deficits in visual-perceptual-organizational psychomotor coordination and complex tactile-perceptual skills appeared to be most representative (in the sense of most discriminative) of the NDL syndrome in the children examined. These are also the dimensions that are considered to be "primary" in the NLD model (Rourke, 1989). Replication of these results, employing children with other clinical disorders, is necessary.