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Purpose: To characterize cyclic day-night patterns of electrocorticographic epileptiform activity (EA) in patients with focal onset seizures., Methods: Epileptiform events as defined by the physician (also termed more generally as "epileptiform activity" or EA) were recorded in 65 patients with partial onset (also referred to as "focal onset") seizures using the RNS System, which includes a cranially implanted neurostimulator connected to 1 or two 4-contact leads placed at the seizure focus. The neurostimulator is programmed to detect specific patterns of electrocorticographic activity and to provide responsive stimulation. The 24-hour periodicity of detections of EA was analyzed for individual patients and for subgroups of patients according to the type of EA, laterality, lobe of onset, and whether the onset was neocortical or hippocampal. The time of day when peaks in EA occurred was also analyzed., Results: There were robust circadian patterns of detections of EA in most patients, with a primary peak in detections at night and a secondary peak in the late afternoon in some cases. Subset analyses were performed by lobe, region of the brain, and type of cortex (neocortical vs. hippocampal); significant circadian rhythmicity was present in all subsets., Conclusions: This is the first report of circadian cycles of EA as assessed through chronic ambulatory electrocorticographic recordings in adults with focal onset seizures. Epileptiform activity displayed circadian patterns in the majority of these patients. These findings suggest that epilepsy therapies might be optimized by adjusting the timing of therapy according to each patient's unique circadian pattern of EA.

This study determined the validity of previously published or newly derived equations to predict fat-free body mass (FFB) in high school wrestlers from the midwestern United States. Five laboratories participated in the data-pooling study (total sample of 860 subjects). Measures included body composition by underwater weighing and anthropometric measurements of body mass, stature, and selected circumferences, diameters, and skinfolds. Cross-validation of selected equations to predict FFB revealed the lowest levels of error from the equations of Lohman, Thorland et al., Katch and McArdle, and Behnke and Wilmore. Modification of the constants in these equations or generation of new equations did not substantially reduce prediction error. Overall, total error for these top equations ranged from 2.44 to 2.59 kg. However, based on observed trends, this error was of lower magnitude with the younger and lighter subjects and of higher magnitude with the older and heavier subjects. We conclude that these equations could be used singularly or collectively to determine FFB, and a minimal weight could then be derived and assigned to a scholastic wrestler.