Auditory Event-Related Potentials P300 in Patients with Schizophrenia: Analysis by Reaction Time / 신경정신의학

OBJECTIVES: Using two stimuli, this study was designed to evaluate variations of P300 in relations to reaction time of pressing the button for target tones in patients with schizophrenia. METHODS: The auditory oddball paradigm was used for the patients (N=22) and normal controls (N=23). The two stimuli were composed of target (20%, 2000 Hz, 75 dB) tone and standard (80%, 1000 Hz, 75 dB) tone, with 2 sec inter-stimulus interval, 50 msec duration and 10 msec rise or fall time. In each subject, P300s were acquired for both fast reaction time (FRT) and slow reaction time (SRT) to target response. RESULTS: P300 amplitude in patients with schizophrenia was lower than controls across FRT and SRT (p0.8). In this study, even though the reaction time for the button pressing task might be faster in patients with schizophrenia (p<0.1), the P300 to FRT in patients with schizophrenia was lower than the P300 to SRT in controls (p<0.01). CONCLUSION: These results suggest that the lower P300 in patients with schizophrenia might be due to cognitive dysfunction and the patient's performance in reaction time for pressing buttons, both independently. Thus, P300 as well as reaction time may be used to further explore a variety of domains of cognitive function.

protein polymorphism of haptoglobin in Korean elite athletes

To investigate protein polymorphism of the haptoglobin [Hp] and the relationship between Hp phenotypes and anthropometric or biochemical parameters in elite Korean male athletes. Materials and Serum samples were collected from 120 Korean male elite athletes. The Hp phenotypes were determined by polyacrylamide gel electrophoresis, followed by peroxidase staining. Then anthropometric or biochemical measurements were made: body composition, blood pressures, ventilatory responses, cholesterol [total, LDL cholesterol and HDL cholesterol], triglyceride, apolipoprotein A1, lipoprotein [a], creatine phosphokinase and lactate dehydrogenase. The gene frequencies of the Hp1-1, Hp2-1 and Hp2-2 phenotypes in Korean male athletes were 12, 37 and 51%, respectively; this polymorphism was significantly associated with the VO2max index in the athletes. An excess of the Hp1 allele was also observed in marathon runners compared with the other sporting activities, although it did not have any statistical significance. Hp polymorphism exists in elite Korean male athletes and Hp phenotype may be a useful marker for endurance performance in these male athletes