Résumé
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.
Sujets)
Humains , Potentiels évoqués , Temps de réaction , SchizophrénieRésumé
OBJECTIVES: Using 3-stimulus auditory "oddball" paradigm reflecting fronto/central and temporo/parietal functions simultaneously, we examined patients with schizophrenia. METHODS: Fifteen patients with schizophrenia from outpatient clinic and fifteen normal controls from hospital staffs were recruited for the study. To elicit P3a and P3b, 3-stimulus auditory oddball paradigm was employed. The 3-stimulus auditory oddball paradigm was composed of standard tone (1,000 Hz, 75 dB, 80%), target tone (2,000 Hz, 75 dB, 10%) and distracter (White noise, 95 dB, 10%). RESULTS: P3a and P3b were prominent in fronto/central and temporo/parietal areas, respectively, in both schizophrenics and normal controls. The P300 amplitude in patients with schizophrenia was reduced across P3a and P3b (p<0.01). The P300 latency in patients with schizophrenia was delayed across P3a and P3b (p<0.01). CONCLUSION: These results were consistent with frontal and temporo-parietal lobe dysfunctions in schizophrenics. The 3-stimulus auditory paradigm could be applied for patients with schizophrenia and useful for further exploration the disorder.
Sujets)
Humains , Établissements de soins ambulatoires , Potentiels évoqués , Bruit , SchizophrénieRésumé
OBJECTIVES: Using 3-stimulus auditory "oddball" paradigm reflecting fronto/central and temporo/parietal functions simultaneously, we examined patients with schizophrenia. METHODS: Fifteen patients with schizophrenia from outpatient clinic and fifteen normal controls from hospital staffs were recruited for the study. To elicit P3a and P3b, 3-stimulus auditory oddball paradigm was employed. The 3-stimulus auditory oddball paradigm was composed of standard tone (1,000 Hz, 75 dB, 80%), target tone (2,000 Hz, 75 dB, 10%) and distracter (White noise, 95 dB, 10%). RESULTS: P3a and P3b were prominent in fronto/central and temporo/parietal areas, respectively, in both schizophrenics and normal controls. The P300 amplitude in patients with schizophrenia was reduced across P3a and P3b (p<0.01). The P300 latency in patients with schizophrenia was delayed across P3a and P3b (p<0.01). CONCLUSION: These results were consistent with frontal and temporo-parietal lobe dysfunctions in schizophrenics. The 3-stimulus auditory paradigm could be applied for patients with schizophrenia and useful for further exploration the disorder.