Alteration of event related potentials in siblings discordant for schizophrenia

This study was aimed at confirming that auditory event related potential (ERP) abnormalities are indicators of vulnerability to schizophrenia. Auditory ERP performances were assessed at Fz, Cz, and Pz, with an oddball paradigm, in 21 clinically stable patients with schizophrenia, 21 of their healthy biological full siblings and 21 control subjects. The evoked response did not differ between the three groups on N200 waves. Compared to controls, patients with schizophrenia exhibited reduced amplitudes of N100 and P300, and prolonged latency of P300, while their siblings showed prolonged latency of P200 and P300. Among the patients with schizophrenia, ERP abnormalities did not correlate with age, clinical state, duration of illness or antipsychotic treatments. Although other conditions also accounted for alterations of the same type, ERP abnormalities may represent a neurobiological marker of the genetic vulnerability to schizophrenia, independent of phenotypic expression.     

Detection of event related potentials

A statistical approach is presented which provides efficient procedures to detect both Event Related Potential (ERP) and its spectral structure. Situations where undesirable signal or "artifact" is present, are considered. In these cases, a "noise" sample can be used which complements the insufficient knowledge given for the sample where we expect to detect the ERP. In this approach, Hotelling's T2 statistic for one and two samples arises as a natural detector of ERPs. Under the assumption of stationarity these statistics are calculated by approximate expressions in the frequency domain. For Brainstem Auditory Evoked Potentials, ROC curves confirm that the T2 statistic has higher detection rates than various indices proposed in the literature. A frequency decomposition of the T2 statistic yields a succession of complex versions of Student's t statistic that characterize the spectral structure of the ERP. Different assumptions about the recordings of ERP are discussed and several generalizations are suggested.     

Using event related potentials to explore stages of facial affect recognition deficits in schizophrenia

Schizophrenia patients show impairments in identifying facial affect; however, it is not known at what stage facial affect processing is impaired. We evaluated 3 event-related potentials (ERPs) to explore stages of facial affect processing in schizophrenia patients. Twenty-six schizophrenia patients and 27 normal controls participated. In separate blocks, subjects identified the gender of a face, the emotion of a face, or if a building had 1 or 2 stories. Three ERPs were examined: (1) P100 to examine basic visual processing, (2) N170 to examine facial feature encoding, and (3) N250 to examine affect decoding. Behavioral performance on each task was also measured. Results showed that schizophrenia patients' P100 was comparable to the controls during all 3 identification tasks. Both patients and controls exhibited a comparable N170 that was largest during processing of faces and smallest during processing of buildings. For both groups, the N250 was largest during the emotion identification task and smallest for the building identification task. However, the patients produced a smaller N250 compared with the controls across the 3 tasks. The groups did not differ in behavioral performance in any of the 3 identification tasks. The pattern of intact P100 and N170 suggest that patients maintain basic visual processing and facial feature encoding abilities. The abnormal N250 suggests that schizophrenia patients are less efficient at decoding facial affect features. Our results imply that abnormalities in the later stage of feature decoding could potentially underlie emotion identification deficits in schizophrenia.     

Relations among intelligence, executive function, and P300 event related potentials in schizophrenia

Prior research has demonstrated that the P300 response may be related to neuropsychological functioning in nonclinical samples. However, the nature of this relation is unclear, and its characteristics in schizophrenia are unexplored. We assessed estimated IQ, neuropsychological tests that assess components of executive functioning, and the P300 component of the event-related brain potential elicited by auditory and visual oddball paradigms in individuals with and without schizophrenia. We observed modest relations between P300 indices and neuropsychological tests purported to assess aspects of executive functioning in both diagnostic groups. Furthermore, multiple regression analyses revealed that whereas control participants with higher estimated IQs demonstrated larger P3 amplitudes to attended auditory targets, the opposite relation appeared evident in schizophrenic participants when variance due to Trailmaking A or a continuous performance task was held constant. Additionally, control participants with higher estimated IQs demonstrated shorter P3 latencies to attended visual targets whereas schizophrenic participants did not when variance due to the Tower of London was held constant. These results suggest diagnostic group differences in the association between P300 and IQ and indicate that investigations designed to explore P300-IQ relations should include measures of executive functioning in their models.     

Changes in event related potentials during processing of Stroop stimuli.

In a simplified Stroop test, subjects responded with a button press to either the color or word dimension of Stroop stimuli. Response times were analyzed as a function of condition (color or word), stimulus type (congruent or noncongruent color-word pairing) and visual field of presentation (left or right). Changes in the stimulus evoked potential (Experiment I) and the preresponse (premotor) potential (Experiment II) were measured as a function of the independent variables and hemisphere of recording site. Stimulus type had the expected Stroop effect on response time, with noncongruent stimuli associated with longer RTs. The pattern of changes in the event related potentials suggested that the typical Stroop interference effect (color condition) is localized in the response selection stage of processing. However, the less common reverse Stroop effect (word condition) probably results from more complex processing interactions during encoding of the color and word dimensions.     

Proprioceptive event related potentials: gating and task effects.

OBJECTIVE: The integration of proprioception with vision, touch or audition is considered basic to the developmental formation of perceptions, conceptual objects and the creation of cognitive schemes. Thus, mapping of proprioceptive information processing is important in cognitive research. A stimulus of a brisk change of weight on a hand held load elicit a proprioceptive evoked potential (PEP). Here this is used to examine early and late information processing related to weight discrimination by event related potentials (ERP). METHODS: A gating paradigm having 1s between the proprioceptive stimuli of 100 g weight increase was recorded in 12 runs of 40 pairs and an 1:4 oddball task of discriminating between 40 and 100 g weight increase was both recorded in 24 healthy men. The subjects were stratified in 3 groups according to their discrimination errors. RESULTS: The proprioceptive event related potential (PERP) consisted of a contralateral parietal P60, frontal N70, midline P100, initial contralateral later widespread N160, vertex P200, parietal N290 and target related widespread P360 and posterior N500. The target related components were augmented in the best performers, while the bad performers had delayed P60 and attenuated N70. The amplitudes of N160, P200 and N290 were unrelated to performance. Gating was seen as attenuation of P100, N160 and P200 amplitude. CONCLUSIONS: The proprioceptive stimulus feature processing seem to be accomplished in the first 100 ms, while later components are modified by context as expected from previous findings in the somatosensory modality. SIGNIFICANCE: The PERP could be a useful research tool in the investigation of bodily information processing in neuropsychiatric disorders.     

事件相关电位在儿童注意力缺陷多动综合征中的应用研究

目的为了揭示注意力缺陷多动综合征（ＡＤＨＤ）患儿的认知能力，量化注意力缺陷的程度及探讨它们之间的关系。方法本文对４０例ＡＤＨＤ和２０例正常对照儿童进行了事件相关电位（ＥＲＰ）Ｐ３波的检测，同时用注意力缺陷测试仪进行评分。结果ＡＤＨＤ患儿Ｐ３波波幅显著下降、潜伏期明显延长（Ｐ＜００１）。注意力缺陷评分重度组较轻度组Ｐ３波波幅低，潜伏期长（Ｐ＜００５）。结论提示ＡＤＨＤ患儿存在一定程度认知功能障碍，并随注意力缺陷程度的增大而加重。     

事件相关电位评估反应抑制功能的研究进展

反应抑制是指要求抑制与当前任务无关但具有支配性的想法或行为的能力,是执行功能的核心组成部分.反应抑制一般被分为3类:抑制无关刺激的激活,制止已经被激活但与当前任务无关的行为准备状态,抑制优势反应[1].事件相关电位(Event Related Potentials,ERP)是观察脑活动过程的窗口,能够反映一定的心理活动(即事件)引起的脑电位变化,与信号感知、注意、辨别分析、工作记忆等认知过程相关[2],其中Go/Nogo范式用于反应抑制的检测,涉及对冲突的监控、行为选择、认知控制等反应抑制过程.本文主要就Go/Nogo范式在神经疾病及精神疾病中对抑制控制功能的评估做一综述.     

Temporal variability of somatosensory, visual, and auditory evoked potentials in schizophrenia.

Previous findings in chronic schizophrenics showed greater than normal somatosensory evoked potential (SEP) waveshape stability before 100-ms after stimulus and reduced stability after 100 ms. To confirm and extend these findings, EPs to left and right median nerve stimuli, visual pattern flashes (VEPs), and auditory clicks (AEPs) were recorded from 14 locations in 86 patients and 33 controls. Three sets of analyses compared different patient groups with age- and sex-matched controls. The results confirmed previous SEP findings in chronic schizophrenics; no other subject group displayed the combination of high early and low late SEP stability. The SEP results did not generalize to VEPs and AEPs. Lead location was important for group differences. In overt schizophrenics, late epoch stability was low in all EPs. The results suggest certain limitations to the hypothesis of an impaired subcortical filtering mechanism in chronic schizophrenics.     

Auditory event related potentials in children with peripheral hearing loss

ObjectiveThe aim of the study was to investigate the neurophysiological responses in children with hearing loss.MethodsCortical auditory evoked potentials and Mismatch Negativity (MMN) Responses were recorded in 40 children, 9–12 years old: 12 with hearing loss, 12 with central auditory processing disorder (CAPD) and 16 with normal hearing. Passive oddball paradigms were used with nonverbal and verbal stimuli.ResultsFor P1, no significant group differences were observed. A significant reduction in N2 amplitude with all stimuli was observed in the group of children with hearing loss compared to the results of those with normal hearing. N2 results did not reveal any significant differences between the group of children with hearing loss and the children with CAPD. MMN amplitude indicated a trend toward larger MMN amplitude among the group of children with hearing loss compared to the value of those of children with CAPD.ConclusionsAbnormal N2 characteristics could be a manifestation of a specific signature in children with hearing loss. This cortical response could be considered as a neurophysiologic marker of central auditory processing deficits in these children.SignificanceResults suggest maturational delays and/or deficits in central auditory processing in children with hearing loss.     

Single trial analysis of event related potentials: non-linear de-noising with wavelets.

We present and apply a method for single trial analysis of event related potentials (ERPs) that combines techniques from non-linear time series analysis with the wavelet transform. For this method, convincing results have already been achieved for simulated data as well as for intracranially recorded ERPs (Physica D 140 (2000) 257). However, ERPs are affected by a variety of external and internal experimental parameters, which makes the appropriate configuration of single trial analysis difficult. Thus, several pitfalls may occur in realistic applications. In this paper, we applied the method of non-linear de-noising with wavelets to both intra- and extracranially recorded ERPs, and show examples of how and where this single trial analysis can be used to obtain additional information on dynamic neural processes.     

Relationship between hepatic injury status and event related potentials

Visual, auditory and somatosensory event related potentials were recorded from 58 patients with chronic nonalcoholic liver disease. The results of this study indicate that a significant, although somewhat modest, amount of variance on brainstem auditory, pattern visual and somatosensory ERP latency can be predicted by routinely obtained liver functional measures, albumin, prothrombin time, fasting ammonia level, globulin and especially indocyanine green clearance. Moreover, these associations are present in persons who are not overtly encephalopathic, underscoring the sensitivity of neurophysiologic measurement for detecting hepatic encephalopathy concomitant to only moderate severity of hepatic injury.     

Systematic review of cognitive event related potentials in euthymic bipolar disorder

Cognitive deficits are critical features of bipolar disorder (BD), greatly impacting quality of life. The aim is to systematically review and critically evaluate underlying event related potential (ERP) features in euthymic BD relating to differences in sensory processes, attention, inhibition and conflict monitoring compared with healthy controls. 911 unique articles were identified using the PubMed database and 14 studies met the inclusion criteria. Individuals with BD in a euthymic state have reduced P50 sensory gating and reduced P100 amplitudes compared with healthy controls. Many studies demonstrated reduced P300 amplitudes and normal P300 latencies in BD. In addition, reduced NoGo N2 and abnormal NoGo P3 activity were observed in BD. Finally, there is some evidence of reduced error-related negativity amplitudes in BD. Importantly, ERP modulations vary with stimulus factors and clinical profile. The functional significance of these findings and clinical implications are discussed. ERP differences in BD arise at various stages of cognitive processing, specifically in early auditory and visual processing, attention allocation, context updating, inhibition and conflict monitoring. Treating these deficits and their underlying neurobiological disturbances corresponding to abnormal performance on cognitive tasks may aid functional remission. This knowledge might enable personalized treatment interventions targeting specific cognitive deficits.     

Comparison of event related potentials with and without hypnagogic imagery

Abstract It is hypothesized that when hypnagogic imagery occurs, an appropriate attention may allocate to the imagery, resulting in the allocation of attention to the external tone stimuli being diminished. N3 amplitude of event related potentials (ERP) obtained a significant difference between the conditions with and without imagery. Arousal level of behavior and electroencephalography were not different between the conditions, therefore it is interpreted that the decrease of the N3 amplitude during imagining reflects the diminution of the allocation of attention to the external tone stimuli. Another late component of ERP, P3, did not make clear peaks in this study despite a large time constant (τ= 3.2 s) used for EEG records.     

P300 of auditory event related potentials in occupational chronic solvent encephalopathy

This retrospective study characterized the P300 component of the auditory event related potential (ERP) and assessed its diagnostic value in occupational chronic solvent encephalopathy (CSE). The P300 was recorded on 86 CSE patients by the classical oddball paradigm. In addition to the laboratory's reference values, we used an age and education matched control group that consisted of 104 blue-collar workers with no known occupational solvent exposure. The association of P300 values with solvent exposure indices, major depression, alcohol consumption, and neuropsychological parameters was studied. The P300 amplitude was lower in CSE patients (mean 7.5 microV; S.D. 3.6) compared to laboratory controls (mean 11.8 microV; S.D. 4.1; F(1,167)=24.4; p<0.001, 95% CI -4.4 to -1.8) and to matched controls (mean 9.0 microV; S.D. 4.0; p=0.007, 95% CI -2.6 to -0.4). The P300 latency was longer in the CSE patients (mean 358 ms; S.D. 28) compared to laboratory controls (mean 339 ms; S.D. 19, F(1,167)=7.6, p=0.006, 95% CI 3.12-18.7) but did not differ from matched controls (mean 358 ms; S.D. 22; p=0.947, 95% CI -7.4 to 6.9). The solvent exposure indices, major depression, or alcohol consumption did not associate with the P300 values. The P300 amplitude correlated positively with the Digit Symbol test. All the amplitude values in the patient group and in the matched control group were classified as normal (i.e. age corrected mean+/-2.5S.D.) against the laboratory's reference values. Thirty percent of the latencies in the CSE patient group and 26% in the matched control group were classified as abnormal. At group level, the decreased P300 amplitudes in CSE patients may reflect solvent-related pathophysiology. However, the P300 measured with the classical oddball paradigm does not seem to be sensitive at individual level or useful in clinical practice.     

Auditory event related potentials and source current density estimation in phonologic/auditory dyslexics.

OBJECTIVE: To determine the generality of auditory processing impairment in phonologic dyslexics by studying their auditory Event-Related Potentials (ERPs) and the spatio-temporal distribution of their brain activity to auditory linguistic and non-linguistic stimuli with temporal and spectral discriminating cues. METHODS: Fourteen adult phonologic dyslexics and 14 normal reading students, all with high academic achievements, were compared. ERP waveform analysis and current density source estimation (Low resolution Electromagnetic Tomographic Analysis-LORETA) were conducted on 21-channel records from subjects who passively listened or actively discriminated 4 types of auditory stimuli: linguistic and non-linguistic stimuli that differed in spectral or temporal characteristics. RESULTS: Significant differences were found for all ERP latencies (N1, P2, N2, P3) in response to all stimuli, with dyslexics presenting longer latencies compared to normal readers. Current density distributions and their time courses also differed significantly, regardless of stimulus type or attention allocation. Among normal readers, early activity (around N1) was characterized by a rapid change of maximum activity from right to left temporal lobe. Later activity (around P3) was characterized by a stable temporal activity with bilaterally synchronous peak activity. Among the dyslexics, the early N1 activity was stable with left hemisphere prominence, with no alternation between the hemispheres, while the later P3 activity peaked earlier in the right hemisphere than in the left. CONCLUSIONS: Dyslexics were different from controls in processing all auditory stimuli: verbal and non-verbal stimuli with temporal as well as with spectral discriminating cues. The differences mainly consisted of latency and time courses of current density distributions, beginning as early as N1 and extending to the late P3. SIGNIFICANCE: Differences in processing auditory stimuli by phonologic dyslexics are not restricted to linguistic (phonological) stimuli, supporting a general auditory processing impairment in phonologic dyslexia.     

Second pain event related potentials to argon laser stimuli: recording and quantification.

A non-invasive technique for quantification of argon laser induced burning second pain (C-fibre) is suggested. Using frequency analysis event related responses to burning pain can be detected in the EEG interval 1-2 seconds after laser stimulation. When the laser stimulus induced a burning pain perception, the power from 0.5-2.5 Hz of the EEG interval 1-2 seconds after stimulation differed significantly from the power calculated from the same time interval when no burning pain was perceived.     

First pain event related potentials to argon laser stimuli: recording and quantification.

Argon laser induced event related responses to pricking pain (first pain) were recorded. The different recording parameters (recording site, filter setting, averaging technique), quantification parameters (amplitude, power) and variability between successive recordings were studied. The single responses were large, and averaging of 16-32 single trials was sufficient to obtain reliable averaged responses. The power (0.5-7.5Hz) of the averaged vertex recorded response was, for the range of intensities considered, the most sensitive parameter to quantify the stimulus and hence the intensity of pain perceived.