We investigated event-related potentials (ERPs) to estimate the accuracy of eyewitness memories. Participants watched videos of vehicles being driven dangerously, from an anti-impaired driving initiative. The four-letter license plates of the vehicles were the target stimuli. Random numbers were presented while participants attempted to identify the license plate letters, and electroencephalograms were recorded. There was a significant difference in activity 300-500 milliseconds after stimulus onset, between target stimuli and random numbers. This finding contributes to establishing an eyewitness recognition model where different ERP components may reflect more explicit memory that is dissociable from recollection.
Electroencephalography ; Event-Related Potentials, P300 ; Evoked Potentials* ; Licensure ; Memory

BACKGROUND: P300 component of the long latency auditory evoked potentials (LLAEPs) provides information on conscious and cortical funtion. The P300 wave occures only for stimuli that somehow capture the patients attention. Therefore LLAEPs implys a degree of cognitive processing. We studied sedation scale and P300 wave to determine if LLAEPs could be utilized as electrophysiologic predictors of sedation. METHODS: The P300 component of LLAEPs from vertex was recorded from 10 ASA physical status I and II patients undergoing elective surgery while they listened via headphones to a series of clicks which were interrupted unpredictably by a tone burst (2 KHz) before and after diazepam 0.04 mg/kg and 0.08 mg/kg IV. The patients were asked to concentrate on the clicks and to press a button whenever they detected a 2 KHz tone. And sedation scale also was measured. RESULTS: Amplitude of P300 was decreased and latency of P300 was increased in a dose-dependent manner with IV diazepam. Amplitude was greatest and latency was shortest in awake. And sedation scale also was increased according to increased IV diazepam adminstration. CONCLUSIONS: Both amplitude and latency may be highly related to the sedation scale with progressively increasing dose of diazepam. Therefore we conclude that P300 component of LLAEPs can be utilized as an electrophysiologic predictor of awareness and sedation.
Diazepam* ; Event-Related Potentials, P300* ; Evoked Potentials, Auditory* ; Humans

OBJECTIVE: To evaluate intra-tester reliability of P300 more precisely, this study was designed. Event-related potential (ERP) is the result of endogenous brain response following cognitive stimulus. The P300 component of the human ERP is a positive wave with a latency of 300 ms or greater. Our purpose of this study was to estimate reliability of P300 latency and amplitude with 30 normal persons without head injury, as well as to set up them as the reference values in the event that they would be found to be highly reliable. METHODS: ERP was performed at three separate times on 30 normal adults in their 20s and 30s. We measured P300 latency and amplitude among ERP. RESULTS: P300 latency show excellent reliability with intraclass correlation coefficient (ICC) of 0.81. As to P300 amplitude, reliability was good to fair with ICC of 0.53. Average value of P300 latency was 311.3+/-37.0 ms, shorter than reference value of previous study in Korea. CONCLUSION: P300 latency revealed higher reliability than P300 amplitude, although reliability of P300 was confirmed in both component. After further study including precise mechanism, influence factor on measurement and method standardization, it is expected to be an objective indicator to assess the cognitive state and predict prognosis.
Adult ; Brain ; Craniocerebral Trauma ; Event-Related Potentials, P300 ; Evoked Potentials ; Humans ; Prognosis ; Reference Values

BACKGROUND: Epilepsy and antiepileptic drugs may be associated with cognitive dysfunction. P300 event-related potentials have been used to assess cognitive function. In this study we investigated the effect of antiepileptic drugs on P300 event-related potentials in epileptic patients. METHODS: P300 latency in event-related potentials was recorded during an auditory oddball paradigm in 29 patients, 10 with generalized epilepsy and 19 with partial epilepsy. The relationships between antiepileptic drugs and P300 latency prolongation were analyzed. RESULTS: P300 latency was prolonged in 31% (9/29) patients with epilepsy. There were no significant relationships between etiology of epilepsy, type of seizure, or type of antiepileptic drugs and P300 latency prolongation. The number or serum level of antiepileptic drugs and treatment duration were related to latency prolongation, but these relations were not significant. CONCLUSION: The prolongation of P300 latency in event-related potentials is not significantly related to antiepileptic drug. This finding suggests that P300 may not be a sensitive additional procedure to assess the cognitive status in epileptic patients.
Anticonvulsants* ; Epilepsies, Partial ; Epilepsy ; Epilepsy, Generalized ; Event-Related Potentials, P300 ; Evoked Potentials* ; Humans ; Seizures

OBJECTIVE: Results from various methodological modalities indicate laterality of brain function and information processing abnormalities in patients with schizophrenia. In neurophysiological field, there is particular interest in the P300 component of event related potentials, being recorded during discriminative information processing. A wide literatures documented reduction of P300 amplitudes in schizophrenic patients. The present study was designed to investigate the topographic pattern of amplitudes of P300 in the patients with schizophrenia. METHOD: The subjects were composed of patients (N=20) with schizophrenia by DSM-VI and normal controls (N=20). The Auditory event related potential P300 were measured by "oddball paradigm", which known as a standard method. P300 latency was determined by Global Field Power and amplitudes measured on 5 electrodes (Fz, Cz, Pz, T3, T4) were compared between controls and patients. RESULTS: There were reduction of P300 amplitudes on all 5 cortical areas in patients with schizophrenia compared with normal controls. There is no anterior to posterior effect but also left to right effect in the both groups. CONCLUSION: P300 amplitudes reduction without localization were founded in patients with schizophrenia.
Automatic Data Processing ; Brain ; Electrodes ; Event-Related Potentials, P300 ; Evoked Potentials* ; Humans ; Schizophrenia*

OBJECTIVE: The present study was designed to compare Global field Power Measurement and conventional method in P300 determination. METHOD: The subjects were composed of patients(N=20) with schizophrenia by DSM-IV and normal controls(N=20). The auditory event related potential P300 was measured by "oddball paradigm". P300 components were determined by Global Field Power Measurement and conventional method at 5 electrodes(Fz, Cz, Pz, T3, T4). RESULTS: P300 amplitudes of patients were smaller than those of controls across all electrodes and in both methods, but there was no differential power in P300 determination between two methods. Asymmetry of auditory event-related potential P300 was not shown between patients with schizophrenia and normal controls. CONCLUSION: It is implicated that it depends on clinical situations and research purposes what method of P300 determination will be more appropriate for patients with schizophernia.
Diagnostic and Statistical Manual of Mental Disorders ; Electrodes ; Event-Related Potentials, P300 ; Evoked Potentials ; Humans ; Schizophrenia

OBJECTIVES: The purpose of this study was to investigate the neurocognitive and psycho-physiological effects of total sleep deprivation by using the objective and quantifiable methods of Vienna Test System (Reaction Unit, Cognitrone, Vigilance) and P300 event-related potential. METHODS: Thirty healthy medical students(22 men, 8 women) participated in this study. Subjects remained awake for 38 hours under continuous surveillance. In the morning and the evening of two consecutive study days, the Vienna tests and P300 were performed. RESULTS: In Vigilance test of the Vienna Test System, a significant functional impairment occurred as a result of total sleep deprivation(p<.001). In Reaction unit, reaction time significantly increased (p<.01). However, in Cognitrone, a functional improvement was revealed. The P300 latency was significantly prolonged(p<.001) and amplitudes decreased(p<.01) as a consequence of total sleep deprivation. Comparing the results of Vigilance and Reaction unit each taken in the morning and evening, the performance decrements were prominent in morning sessions. In Cognitrone, evening session result showed the improvemed performance. CONCLUSIONS: The cognitive impairment resulting from 38 hours of sleep deprivation are considerable in alertness and reaction time tests, but not in higher complex cognitive functions such as fine perceptual analyses, visual discrimination, and short term memory. Considering the results with P300 latency and amplitudes, it may be concluded that the P300 changes as a result of total sleep deprivation are due to the decrement in the alertness which prolongs reaction time. More deterioration of cognitive performance shown in the morning, could be explained by considering circadian rhythm.
Circadian Rhythm ; Discrimination (Psychology) ; Event-Related Potentials, P300 ; Humans ; Male ; Memory ; Reaction Time ; Sleep Deprivation*

OBJECTS: This study was designed to make a comparison between methods to determine the components of topographic auditory event related potential P300. METHODS: The subjects were consisted of 44 normal controls and 44 patients with schizophrenia diagnosed by DSM-IV. The topographic auditory event related P300 was recorded in oddball paradigm. The components of P300, including latency, amplitude, and location of maximum amplitude in X-Y coordinates, were analized by computerized EP mapping system. The latency of P300 was determined by both global field power measurement and classic method. RESULTS: There was difference between two groups in latency(DF=1, F=35.28, P= 0.0001) and amplitude(DF=1, F=36.62, P=0.0001), but not in X coordinate(DF=1, F=0.37, P=0.55) and Y coordinate(DF=1, F=2.00, P=0.16). There was no difference between two mothods in latency(DF=1, F=0.04, P=0.85), in amplitude(DF=1, F=0.07, P=0.79), in X coordinate(DF=1, F=0.07, P=0.79), and in Y coordinate(DF=1, F=0.03, P=0.86). CONCLUSION: The results suggested that two methods to determine the components of topographic auditory event related potential P300 should be available for both research and clinical application to date.
Brain* ; Diagnostic and Statistical Manual of Mental Disorders ; Event-Related Potentials, P300* ; Humans ; Schizophrenia

Using electroencephalogram (EEG) signal to control external devices has always been the research focus in the field of brain-computer interface (BCI). This is especially significant for those disabilities who have lost capacity of movements. In this paper, the P300-based BCI and the microcontroller-based wireless radio frequency (RF) technology are utilized to design a smart home control system, which can be used to control household appliances, lighting system, and security devices directly. Experiment results showed that the system was simple, reliable and easy to be populirised.
Brain ; physiology ; Brain-Computer Interfaces ; Electroencephalography ; Event-Related Potentials, P300 ; Humans

Adult ; Event-Related Potentials, P300 ; physiology ; Female ; Follow-Up Studies ; Humans ; Male ; Schizophrenia ; physiopathology