Efficacy of repeated psychophysiological detection of deception testing.

Physiological measures were recorded during repeated psychophysiological detection of deception (PDD) tests to determine if reaction levels change with test repetition. Two groups of 22 healthy male subjects completed six peak of tension PDD tests on each of two test days. A minimum between test day interval of six days was maintained. The treatment group was programmed to respond deceptively to one of seven test questions while the control group was programmed to respond truthfully to all questions. The respiration and galvanic skin resistance (GSR) line lengths, GSR peak response amplitude and latency, and cardiovascular inter-beat-interval (IBI) were calculated for each response. Analyses indicated that, except for GSR peak response latency, differential physiological reactivity during a PDD test did not change significantly over repeated tests or days; there was a decrease in average respiration line lengths at the initial test(s) of each day; and differential changes in average respiration line length, GSR peak latency, and cardiovascular IBI responses corresponded to deception. Power analyses were calculated to assist in result interpretation. It is suggested that PDD decision accuracy, concerning subject veracity, should not decrease during repeated testing.

Evaluation of the lysis-centrifugation system for culturing dialysates from continuous ambulatory peritoneal dialysis patients with peritonitis.

Recovery of organisms from continuous ambulatory peritoneal dialysis (CAPD) patients with peritonitis presents special problems to the laboratory. The Isolator (Dupont Co, Wilmington, DE), based on lysis and centrifugation, is generally used for the recovery of blood isolates. This study determined the efficacy of the Isolator relative to the Bactec System (Johnston Laboratories, Inc, Towson, MD) for the culture of dialysates from CAPD patients with peritonitis. On the basis of clinical criteria, 31 episodes of peritonitis were included for our study. Dialysate was inoculated into an Isolator and Bactec 6B and 7D bottles. A causative agent was isolated by the Isolator in 29 of 31 episodes, by the Bactec in 29 of 31, and by one or both techniques in 30 of 31 episodes (overall sensitivity 97%). The Isolator failed to detect a Pseudomonas luteola and the Bactec failed to detect a coagulase-negative staphylococcus. Coagulase-positive and negative staphylococci represented 58.1% of the isolates. The Isolator detected 21.4% (six of 28) of the isolates 24 to 72 hours earlier than the Bactec; the Bactec was faster in this regard in 3.6% (one of 28). Time to positivity for the remaining 21 cultures was the same in both systems. Isolate identification and antimicrobial sensitivity was available 24 hours earlier using the Isolator in 96.4% (27 of 28). The Isolator was more rapid and as sensitive as the Bactec system in detecting causative organisms of peritonitis in CAPD patients.