Summary: Purpose: To determine the efficacy and relative contribution of several diagnostic methods [ictal and interictal scalp and intracranial EEG, magnetic resonance imaging (MRI), and magnetoencephalography (MEG)] in identifying the epileptogenic zone for resection.Methods: This was a prospective study using a masked comparison-to-criterion standard. Fifty-eight consecutive patients with refractory partial epilepsy from two university comprehensive epilepsy programs were studied. Patients who were evaluated for and underwent epilepsy surgery were recruited. The main outcome measure was the efficacy of each diagnostic method to identify the resected epileptogenic zone, when referenced to surgical outcome.Results: MEG (52%) was second only to ictal intracranial V-EEG in predicting the epileptogenic zone for the entire group of patients who had an excellent surgical outcome (seizure free or rare seizure). In a subanalysis, for patients who had temporal lobe surgery, this same relation was seen (MEG, 57%, ictal intracranial V-EEG, 62%). With extratemporal resection, ictal (81%) and interictal (75%) intracranial EEG were superior to MEG (44%) in predicting the surgery site in those patients with an excellent outcome. Finally, for all patients who had a good surgical outcome, MEG (52%) was better than ictal (33%) or interictal (45%) scalp VEEG in predicting the site of surgery.Conclusions: These results indicate that MEG is a very promising diagnostic method and raise the possibility that it may obviate the need for invasive EEG in some cases or reduce the length of scalp EEG evaluation in others.

We derived interhemispheric asymmetry indices (AIs) in interictal glucose uptake and blood flow in the temporal lobes of patients with intractable complex partial seizures from 18F and 15O positron emission tomograms. All patients subsequently underwent either left (n = 16) and right (n = 18) temporal lobectomy. We determined the effects on AIs of clinical seizure variables, including duration of seizure disorder, age at seizure onset, frequency of complex partial seizures, history of secondary generalization, history of febrile seizures, and magnetic resonance imaging evidence for mesial temporal sclerosis. Duration of seizure disorder produced the only significant effects. Degree of interhemispheric asymmetry in both glucose uptake and blood flow increased with duration of seizure disorder. However, the rate of increase in asymmetry was significantly greater for glucose uptake than for blood flow. These results indicate that uncoupling of metabolism and blood flow is a progressive process that results from the differential response of glucose metabolism and blood flow to chronic seizure activity. The results also suggest that duration of seizure disorder may be an important variable to consider in the interpretation of PET studies for evaluation of seizure surgery candidates.

Objectives:To contrast and compare self-reported quality of life in patients with intractable epilepsy and pseudoseizures and to examine the relationship between selfreports and objective measures of cognitive functioning in both of these groups.Design: Case series using profile analysis and analysis of covariance.Setting: University epilepsy surgery program.Participants: Forty-three patients with intractable complex partial seizures of unilateral temporal lobe origin and 25 patients with pseudoseizures.Measures: Quality of Life in Epilepsy Inventory-89; neuropsychological tests assessing verbal memory, nonverbal memory, naming, and attention; and the Depression Scale (2) of the MMPI-2 (Minnesota Multiphasic Personality Inventory).Results: Patients with pseudoseizures described themselves as more limited in the physical health domain than ORIGINAL CONTRIBUTION

We examined the ability of preoperative memory performance to distinguish between patients who had been diagnosed as having left (LTLE, n = 31), right (RTLE, n = 37), and extra-(ETLE, n = 17) temporal lobe focal epilepsy. All patients eventually underwent surgical resections. Analyses indicated that the ETLE group performed better than the RTLE group on nonverbal memory measures and better than the LTLE group on verbal memory measures. Discriminant function analyses indicated that use of a combination of measures that assess different aspects of memory were of significant value in distinguishing between patients with focal TLE and ETLE. This approach, as compared the use of single measures, improved classification rates of all three groups. The best single predictor of group membership, an index of verbal learning, yielded a 47% overall correct classification rate, with sensitivities ranging from 25 to 59%, and performed at worse than chance levels in classifying RTLE patients. A multivariate approach, which included an index of verbal and nonverbal learning, incidental nonverbal memory, and consolidation of organized and rote verbal material, yielded a 65% correct classification rate, with sensitivities ranging from 57 to 75%. This compares favorably with the other noninvasive techniques for lateralizing epileptogenic lesions.

The preoperative delayed memory performance on the Rey-Osterrieth Complex Figure (Lezak, 1983) of 54 patients with complex partial seizures of temporal lobe origin was analyzed using 3 different indices. One index (composite) was derived using a common scoring method that included both spatial and figural aspects of memory in its score. The other two indices were derived emphasizing either spatial or figural aspects of memory for the elements of the figure separately. All 3 indices distinguished between individuals with right-sided (RTLE) and left-sided (LTLE) seizure onset. However, spatial memory was significantly lower than figural memory in individuals with RTLE as compared to those with LTLE. Both the spatial and figural memory indices were significantly lower in the presence of magnetic resonance imaging (MRI) evidence for hippocampal selerosis in individuals with RTLE. Results suggest that while both the spatial and figural aspects of nonverbal memory are sensitive to right hippocampal dysfunction, figural memory may be less vulnerable to the effects of RTLE. (JINS, 1996, 2, 535–540.)