Biomedical subjects
P J Dorio
Publications and source records attributed to P J Dorio.
Reduced P3b category response in prefrontal patients.
Several studies have implicated a frontal/prefrontal contributor to P3b. We hypothesized that prefrontal involvement may be necessary to the processing of novel contextual information, as suggested by selective reduction of P3a in prefrontal patients. ERPs were recorded from 12 controls and 12 unilateral prefrontal lesion patients. In two target-detection tasks, subjects/patients viewed randomly-ordered stimuli drawn from differentially probable categories: numbers (standard, 90%) and letters (deviant, 10%). Topographic and midline analyses were applied to examine target and category effects on P3b. Low-probability targets evoked distinct P3bs in each group. Control subjects' P3bs were additionally enhanced to deviant targets and nontargets. Patients' P3s were enhanced to deviant nontargets but were unaffected by deviant targets. This is consistent with the view that target- and nontarget-evoked P300s are functionally distinct, and suggests that a prefrontal contributor to P3b supports attention to contextual attributes among task-relevant stimuli.
Non-contrast-enhanced helical computed tomography for the evaluation of patients with acute flank pain.
The purpose of this study was to determine the sensitivity, specificity, and positive predictive value of non-contrast-enhanced helical CT as the primary imaging modality for the evaluation of patients with acute flank pain at the University of Wisconsin. A retrospective review of 163 computed tomography (CT) examinations, dating from 3/4/97 to 3/25/98, was performed. Statistical calculations were performed using only clinically-confirmed data. Sixty-five true positives, 3 false positives, 64 true negatives, and 1 false negative yield a sensitivity of 98.5%, a specificity of 95.5%, and a positive predictive value of 95.6%. A timely diagnosis of non-genitourinary system pathology occurred in 7% of cases, improving the overall efficacy of this modality for the evaluation of flank pain. The University of Wisconsin experience confirms the accuracy and efficacy of using non-contrast-enhanced helical CT in the diagnosis of a suspected obstructing ureteral calculus. The highly accurate and timely diagnosis of an obstructing ureteral calculus, or of extraurinary tract pathology, establishes non-contrast-enhanced helical CT as the diagnostic study of choice for the evaluation of the patient with acute flank pain.