We evaluated the role of positron emission tomography (PET) with [18F]deoxyglucose (FDG) (FDG-PET) for planning surgery in 53 patients who had temporal lobectomy for uncontrolled seizures at National Institutes of Health from 1981 to 1990. Investigators blinded to PET data used results of telemetered video-electroencephalographic ictal monitoring and other standard criteria to decide whether subdural electrodes (22 patients, i.e., the "invasive" group) should be implanted or surgery performed. PET scans were analyzed using a standard regional template. Mean lateral but not mesial temporal asymmetry was significantly higher in patients who became seizure free (p < 0.03). Patients with > or = 15% hypometabolism were significantly more likely to be seizure free in the entire study population and the invasive subgroup. Visual identification of hypometabolism was less accurate. When a clear temporal ictal surface electroencephalographic focus was present, FDG-PET provided less additional information. FDG-PET may be particularly valuable if the surface electroencephalographic scan is nonlocalizing. In addition to helping to identify the seizure focus, it may allow limitation of invasive electrode placement to those necessary for functional mapping. When PET is used to identify epileptic foci, quantitative measurements of asymmetry should be made.

No abstract

A critical component in development of opioid analgesics is assessment of their abuse liability (AL). Standardization of approaches and measures used in assessing AL has the potential to facilitate comparisons across studies, research laboratories, and drugs. The goal of this report is to provide consensus recommendations regarding core outcome measures for assessing abuse potential of opioid medications in humans in a controlled laboratory setting. Although many of the recommended measures are appropriate for assessing the AL of medications from other drug classes, the focus here is on opioid medications because they present unique risks from both physiological (e.g., respiratory depression, physical dependence) and public health (e.g., individuals in pain) perspectives. A brief historical perspective on AL testing is provided and then those measures that can be considered primary and secondary outcomes and possible additional outcomes in AL assessment are discussed. These outcome measures include: (1) subjective effects (some of which comprise the primary outcome measures, including drug liking); (2) physiological responses; (3) drug self-administration behavior; and (4) cognitive and psychomotor performance. Prior to presenting recommendations for standardized approaches and measures to be used in AL assessments, the appropriateness of using these measures in clinical trials with patients in pain is discussed.

We studied the effects of valproate (VPA) on local cerebral glucose metabolism (LCMRglc) in eight patients with partial seizure disorders and two with primary generalized epilepsy. Each patient had two positron-emission tomography (PET) scans with 18F-2-deoxyglucose (FDG), with, and without, VPA (mean level 52 mg/dl, range 30-127 mg/dl). Patients continued carbamazepine (CBZ) for both scans: serum concentrations were not significantly changed by VPA (CBZ range 5.4-12 mg/dl). Seven patients had the "without-VPA" scan first. Mean interval between PET scans was 75 days. Global CMRglc was decreased by 22% by addition of VPA (7.2 +/- 1.8 mg/100 g/min without VPA, 5.6 +/- 1.1 g/min with VPA, p less than 0.05, corrected). Thirteen regions of interest (ROIs) were analyzed in each hemisphere in each PET scan. Metabolic rates were significantly lower in 15 of 26 ROIs with VPA (p less than 0.05, corrected). VPA depresses cerebral metabolism to a greater degree than do CBZ and phenytoin (PHT) but less than does phenobarbital (PB). The metabolic effect may be related to the mechanism of action and have neuropsychological implications.