Long-term test-retest reliability of event-related potentials in normals and alcoholics.

The long-term test-retest reliability of event-related potentials (ERP) measures was examined in a group of 44 controls and 71 chronic alcoholics, retested after an average of 14 months. Correlational analyses revealed moderately significant test-retest correlations for visual and auditory target N1, N2, and P3 amplitudes, with significant correlations for N1, N2 and P3 latencies. Controls and alcoholics produced similar test-retest correlations for visual and auditory ERP measures. Men and women produced equally stable ERP measures over time. Overall N1 and P3 amplitudes were most reliable in both groups followed by N2 amplitude, N1 and N2 latency, and P3 latency. The stability of ERP measures found in this study over a 14-month period in both normals and chronic alcoholics supports the use of ERPs in the study of normal and disordered cognitive functioning.     

Cognition in Parkinson disease: An event-related potential perspective

Auditory event-related potentials (ERP) elicited in a target detection stimulus paradigm and pattern-shift visual ERPs were studied in 20 male patients with idiopathic Parkinson disease (PD) and 20 age-matched normal controls. Patients showed significantly increased latencies for both the P200 and P300 components of the auditory ERP. Patients and controls showed no significant differences in latency of the visual ERP but patients showed significantly decreased amplitude. Only one of five neuropsychological measures, the Symbol Digit Modalities test (SDMT), showed a significant negative correlation with P300 latency. The significant association between the two measures that showed impairments in the PD patients (P300 latency and SDMT scores) suggested that these measures reflect a common, disrupted aspect of cognitive function in PD.     

Functional and anatomical memory indices in patients with or at risk for Alzheimer's disease.

We investigated the sensitivity of the P300 event-related brain potential (ERP) recorded during a memory-demanding task to memory function in subjects with dementia of the Alzheimer's type (DAT), those with mild cognitive impairment (MCI), and normal elderly controls. We also explored the ability of neuropsychological (delayed verbal memory), neuroanatomical (MRI-based hippocampal volume), and electrophysiological (memory search P300 amplitude) memory measures to distinguish between the three subject groups using discriminant function analyses. Fourteen patients with DAT, 16 with MCI, and 15 age- and education-matched controls were tested. P300 amplitude was reduced in DAT subjects at all levels of memory load; however, it did not differ between MCI and control subjects. Delayed verbal memory performance best discriminated DAT from MCI and control subjects, while delayed verbal memory and hippocampal volume best discriminated MCI subjects from controls. These results support the utility of neuropsychological and neuroanatomical measures in diagnosing dementia and do not support the notion that P300 amplitude is sensitive to mild memory dysfunction when measured using the current task.     

N100 and P300 amplitude to Go and No-Go variants of the auditory oddball in siblings discordant for schizophrenia

BACKGROUND: P300 amplitude reduction is reliably seen in schizophrenia. Inconsistent reports of isolated frontal and/or parietal deficits in unaffected family members may be clarified using a task that places greater load on frontal function. METHOD: Go and No-Go versions of the auditory oddball task were performed by eighteen schizophrenia patients, age-matched unaffected siblings and healthy controls matched closely to unaffected siblings on age, sex, education, socioeconomic-status, handedness and ethnicity. Groups were compared on P300 and N100 amplitude and latency. Spearman correlations were used to test the relationship between ERP amplitudes and neuropsychological measures of executive function and memory. The relationship between schizotypy--as measured using the structured interview--and ERPs was explored in a combined group of siblings and controls. RESULTS: Independent of task, patients had lower P300 than controls and reduced parietal amplitude compared to siblings. Siblings had enhanced frontocentral N100 compared to controls. No-Go P300 amplitude and N100 latency was associated with executive function measures. There were significant intraclass correlations between patients and siblings for No-Go P300 amplitude, particularly at the central midline electrode. Frontocentral N100 and P300 amplitude were positively correlated with anxiety-related aspects of schizotypy. CONCLUSION: Enhanced N100 is present in unaffected siblings. Parietal P300 is intact in unaffected siblings, but reduced in patients. The No-Go-oddball is more sensitive than the Go-oddball to executive function deficits in patients and as an index of heritability.     

Indices of slowness of information processing in head injury patients: tests for selective attention related to ERP latencies.

We explored the relation between neuropsychological (attention tests involving time constraints) and neurophysiological (N2 and P3 event-related potential (ERP) latencies) indices of slowness of information processing after closed head injury (CHI). A group of 44 CHI patients performed worse than healthy controls on most neuropsychological indices, and had significantly longer ERP latencies. Significant correlations between neuropsychological measures and ERP latencies were found only for the 3 subtasks of the Stroop test. In additional multiple regression analyses P3 latency appeared the best predictor in Stroop Color only. A possible explanation is that stimulus evaluation processes comprise a relatively large part of performance on this subtask. In Stroop Color-Word, response related processes are supposed to play a greater role, reducing the role of the preceding input related processes. The absence of significant correlations between P3 latency and scores on the other attention tests suggests a relatively small role of stimulus evaluation processes in these tasks, implying that these tasks are not sensitive to slowness of these processes. The Stroop test appears to be the only attention test administered in which slowness in stimulus evaluation processes requiring selective attention contributes significantly to the delay in final performance on the task.     

Auditory and visual event-related potentials in alcoholics: abnormalities of components and brain electrical field

Alterations of ERPs recorded over midline scalp sites have frequently been reported in alcoholics. To assess the P3 and other ERP components topographically, auditory and visual ERPs were recorded from 33 scalp electrodes in abstinent alcoholics and healthy controls using an oddball paradigm. At tze Cz electrode the alcoholics showed decreased visual N1 and increased auditory N2 amplitudes. Topographically, the negative centroids of the visual N1 and P3 and the auditory N2 differed between groups, and the positive centroid of the visual P3 was displaced toward the right hemisphere. While no valid diagnostic classification could be obtained by using the traditional ERP component P3 recorded from Pz, the combination of visual N1 and auditory N2 amplitudes at Cz with centroid parameters amounted to 51% explained variance and 92% correct discrimination of alcoholics from controls. Abnormalities of N1 amplitude and P3 topography similar to the current findings in alcoholics have previously been described for schizophrenics. Received: 2 July 1999 / Accepted: 14 April 2000     

Ictal electroencephalographic correlates of posttreatment neuropsychological changes in electroconvulsive therapy: a hypothesis-generation study

OBJECTIVES: Electroconvulsive therapy (ECT) has been associated with memory and neuropsychological changes, but which features of ECT are associated with those changes have not been well investigated. The aim of this hypothesis-generation study was to examine correlations between ictal electroencephalographic (EEG) characteristics and cognitive side effects after ECT. METHODS: Eight patients with major depressive disorder were examined with the Wechsler Memory Scale-Revised (WMS-R), the Stroop test, the Trail Making Test, and verbal fluency before and after ECT treatment. Seven ictal EEG measurements (eg, slow-wave phase amplitude, postictal suppression) were manually rated by 3 independent psychiatrists. The correlations between ictal EEG measurements, changes in WMS-R subset scores, and non-memory-related neuropsychological assessments were examined with Spearman rank correlation. RESULTS: Verbal memory, general memory, attention/concentration, delayed memory of WMS-R subset scores, and the Stroop test scores improved significantly after ECT treatment. Postictal suppression and slow-wave amplitude correlated positively with delayed memory and visual/verbal discrepancy score. Slow-wave amplitude correlated negatively with letter fluency. The longer the polyspike wave duration, the higher the attention/concentration test results. CONCLUSIONS: Certain ictal EEG measurements were associated with changes in several neuropsychological test results that had improved 2 weeks after the final ECT treatment. A hypothesis-testing study with a larger sample is needed to verify the relationships between EEG measurements and neuropsychological test performance.     

The N2 component of the event-related brain potential in abstinent alcoholics

The latencies of the N2 component of the ERP and reaction time were manipulated in abstinent alcoholics and controls. The experimental design consisted of visual stimuli that differed in difficulty of discrimination. N2 latencies were found to be significantly delayed in alcoholics compared to controls, particularly for the easy discrimination. While controls manifested significantly earlier N2 latencies for the easy discrimination compared to the difficult discrimination, alcoholics did not manifest any significant difference in the latency of N2 as a function of the level of difficulty. There were no significant differences between groups in terms of RT or number of errors. In addition, alcoholics displayed significantly reduced P3 amplitudes to target stimuli compared to controls. These results suggest that match/mismatch processes are impaired in alcoholics and that they have difficulty evaluating the potential significance of a stimulus.     

Correlation between Event-Related Potentials and MR Measurements in Chronic Alcoholic Patients

Abstract: Event-related potentials were recorded in 25 abstinent alcoholics, and 25 gender-and age-matched controls during a two-tone discrimination (odd ball) task. All the subjects were free from medication and dextral. MR images were examined in the alcoholics. The amplitudes of N100, N200 and P300 in the alcoholics were reduced compared with those of the controls. In order to identify morphological changes responsible for ERP abnormalities, linear regression analyses were performed between ERP measures and MRI parameters. The amplitude of N100 was inversely correlated with ventricular size. The amplitudes of P300 were inversely correlated with both ventricular size and width of cortical sulci. It was suggested that the N100 abnormality was related to subcortical structure, and P300 alteration was related to both subcortical and cortical structures in the alcoholics.     

Computer-based assessment of memory and attention: evaluation of the memory and attention test (MAT)

Objective A computer-based test for the assessment of working and short-term memory and selective attention was evaluated in Alzheimer patients and controls.Methods By means of the MAT, working and short-term memory for verbal, figural and episodic material are assessed through recognition tasks. Selective attention is tested through visual samples in an oddball paradigm. In 42 Alzheimer patients and 42 controls, we applied the MAT and usual reference methods for the assessment of attention and the respective memory domains.Results The correlations of the scores of the MAT memory subtests with the scores of the reference tests were moderate to high (r: 0.63-0.84). Test-retest correlations were between 0.79 and 0.90. Differentiation of Alzheimer patients and controls was good, particularly in episodic and figural short-term memory (p?相似文献   

Cognitive impairment and cerebral atrophy in "heavy drinkers".

1. Aim of the work was to verify the following three hypotheses in alcoholics: a) right hemisphere; b) diffuse brain deficit; c) anterior brain deficit, by means of a neuropsychological and a neuroradiological assessment. 2. 15 alcoholic right-hand male subjects and 15 matched controls were enrolled in the study. 3. Specifically designed neuropsychological testing was performed to investigate logical abilities, selective attention and memory. 4. Neurological investigation was performed by a standard CT scan to assess the degree and localization of brain damage. 5. Alcoholics performed worse than controls on some neuropsychological tests, i.e. Attention Matrices Test, Verbal Judgement Test, Forward Digit Span, Story Recall and Remote Memory Test. The analysis of variance adjusted by the attentional score showed no significant differences between alcoholics and controls. 6. Neuroradiological data showed a preeminent and a more frequent atrophy of the frontal region. 7. No correlations emerged between neuropsychological and neuroradiological data. 8. In conclusion, the hypothesis of anterior brain deficit seems to be confirmed by our study.     

Assessing cerebral dysfunction with probe-evoked potentials in a CNV task -- a study in alcoholics.

OBJECTIVES: Contrary to event-related potential (ERP) components N1, N2 and P3, slow ERPs have rarely been used in assessing cerebral dysfunction in mental disorders. Focussing on slow waves (SWs) and on patients with mild cerebral dysfunction, we recorded ERPs in alcoholics using a dual task design.METHODS: ERPs to auditory probes presented either 1s before the warning or 1s before the imperative stimulus of a visual contingent negative variation (CNV) paradigm were recorded from 33 scalp electrodes in 27 alcoholics following detoxification and 12 healthy controls. Independent component analysis (ICA) was used to separate potentially overlapping spatial components.RESULTS: In alcoholics compared to controls, probe ERPs showed increased N2, decreased P3 and increased negative SWs of two types appearing pre- and post-P3, respectively. Both negative SWs significantly correlated with neuropsychological indices reflecting verbal intelligence and memory functions. The increase in probe-evoked N1 and P3 potentials during CNV, putatively associated with enhanced cortical excitability, significantly correlated with clinical features of protracted alcohol withdrawal syndrome in alcoholics.CONCLUSIONS: Our experimental approach revealed two types of negative SWs which strongly correlated with neuropsychological deficits of mildly impaired patients. It is suggested that our methods might enhance diagnostic efficiency of ERPs. An electrophysiological measure of protracted alcohol withdrawal might be useful for managing central nervous system dysfunction in alcoholics.     

Relationships between auditory event‐related potentials and mood state,medication, and comorbid psychiatric illness in patients with bipolar disorder

Background: Patients with bipolar disorder (BD) exhibit aberrations in auditory event‐related potentials (ERPs), although the relationships between these measures and mood state at testing, comorbid psychiatric illness, presence of psychotic features, and medication usage are unclear. The purpose of this study was to investigate the relationships between these factors and auditory ERP measures in BD patients. Methods: An auditory ‘oddball’ discrimination task was used to elicit ERPs from 69 patients with type I BD and 52 healthy controls. Patients were placed into subgroups based upon their mood state at testing (euthymic or symptomatic), and ANOVA was used to compare amplitude and peak latency measures from the N100, P200, N200, and P300 ERP components across subgroups. Multiple regression was used to investigate relationships between ERP measures and comorbid psychiatric diagnosis, history of psychotic features, and medication status. Results: Relative to healthy control participants, euthymic and symptomatic BD patients exhibited reduced P300 and P200 amplitude, but ERP measures did not differ among BD patients on the basis of mood status. A history of a comorbid anxiety disorder was associated with reduced N200 peak latency, but prolonged P300 peak latency among BD patients. No other relationships between clinical variables and ERP measures were significant. Conclusions: The results suggest that disrupted auditory attention may be observed in BD patients regardless of their mood state at testing, medication status, or history of psychosis. These results extend previous findings, and provide further evidence for aberrations in the P300 ERP as an endophenotype for BD.     

Semantic (verbal) and figural memory impairment in alcoholics

In two separate studies, episodic semantic (verbal) and figural-memory abilities as measured by the Wechsler Memory Scale (Russell Method) are compared in middle-aged detoxified male alcoholics and controls. Both studies gave rise to similar findings. Alcoholics recalled significantly less verbal and figural material at both immediate recall and 30-min delayed recall than did the controls. Contrary to expectation, compared to controls, alcoholics did not have a greater differential deficit for the figural material as compared with the verbal or a greater differential deficit on delayed than on immediate memory. The percentage of material recalled at the delayed testing, when taken as a function of the amount of material recalled immediately, did not differ for the two groups on the semantic or figural tasks in either study. Thus, rates of forgetting were equivalent in alcoholics and controls suggesting that the alcoholics' deficit lies in the initial acquisition process. Whether that deficit is in encoding or initial retrieval processes remains to be investigated. Implications for future research are given.     

Modality dependent changes in event-related potentials correlate with specific cognitive functions in nondemented patients with Parkinson's disease

Summary The relationship between event-related potentials (ERPs) and cognitive functioning was studied in patients with Parkinson's Disease (PD) but without dementia. Auditory and visual stimuli were used; 30 subjects participated in the auditory study and 20 in the visual study. Patient groups did not differ with respect to gender, age, education, illness duration, and level of cognitive functioning. Visual stimuli were 2.3 cpd sinusoidal grating patterns randomly presented in an oddball paradigm (oblique vs. vertical spatial orientation). Auditory stimuli were tones presented at 70dB SPL at a rate of 1.1/second, also using the oddball paradigm (1.5K vs. 1K tones). All patients were given neuropsychological tests to measure verbal fluency, memory, visual spatial perception, and abstract reasoning. P300 and N200 abnormalities correlated with a number of these measures, such that longer ERP latencies were related to lower scores on tests of cognitive functioning. Patterns of results suggest that auditory and visual ERPs correlate with different subsets of neuropsychological functions in nondemented PD patients and that N200 may provide a new metric for clinical use.     

Auditory event-related potentials in obstructive sleep apnea: effects of treatment with nasal continuous positive airway pressure.

Event-related potentials (ERPs) were recorded in 47 patients with obstructive sleep apnea (OSA) syndrome prior to and after 6 weeks of treatment with continuous positive airway pressure (CPAP). Compared with a control group, the OSA patients showed ERP abnormalities: lengthened P3 latencies and decreased N2-P3 amplitudes. After 6 weeks of CPAP treatment, there was a highly significant improvement in the abnormal ERPs: the P3 and N2 latencies were shortened, but remained longer than in controls, and the N2-P3 and N1-P2 amplitudes were increased. No correlations could be established with various sleep variables. ERPs may be used as an electrophysiological marker of brain dysfunction; treatment of OSA with CPAP is probably responsible for functional brain modifications. On the other hand, possible relationships between the ERP abnormalities and the neuropsychological disorders observed in OSA remain to be established.     

A high-density ERP study reveals latency,amplitude, and topographical differences in multiple sclerosis patients versus controls

ObjectiveTo quantify latency, amplitude and topographical differences in event-related potential (ERP) components between multiple sclerosis (MS) patients and controls and to compare ERP findings with results from the paced auditory serial addition test (PASAT).MethodsFifty-four subjects (17 relapsing remitting (RRMS) patients, 16 secondary progressive (SPMS) patients, and 21 controls) completed visual and auditory oddball tasks while data were recorded from 134 EEG channels. Latency and amplitude differences, calculated using composite mean amplitude measures, were tested using an ANOVA. Topographical differences were tested using statistical parametric mapping (SPM).ResultsIn the visual modality, P2, P3 amplitudes and N2 latency were significantly different across groups. In the auditory modality, P2, N2, and P3 latencies and N1 amplitude were significantly different across groups. There were no significant differences between RRMS and SPMS patients on any ERP component. There were topographical differences between MS patients and controls for both early and late components for the visual modality, but only in the early components for the auditory modality. PASAT score correlated significantly with auditory P3 latency for MS patients.ConclusionsThere were significant ERP differences between MS patients and controls.SignificanceThe present study indicated that both early sensory and later cognitive ERP components are impaired in MS patients relative to controls.     

Early sensory information processes are enhanced on visual oddball and S1-S2 tasks in Parkinson's disease: a visual event-related potentials study

To observe sensory and cognitive information processing in Parkinson's disease (PD), 34 PD patients and 26 controls were investigated. A visual oddball paradigm and an S1–S2 paradigm were employed to record the early (P1, N1, P2) and late (N2, P3) event-related potentials (ERPs) at Cz, Pz and Oz. Results showed: (1) enlarged P1 amplitude at all electrode locations on both tasks, (2) shortened N1 latency and enlarged P2 amplitude at Oz on both tasks, (3) enlarged N1 amplitude at Cz during an oddball paradigm, (4) delayed N2 latency and decreased N2, P3 amplitude on both tasks, and (5) delayed P3 latency and reaction time during the S1–S2 paradigm. Abnormal ERP changes were correlated with worsened scores on Wechsler Adult Intelligence Scale-Revised and motor dysfunction scales in PD. We surmise overactive aspects or failed inhibitory modulation of sensory information processing in the early ERP stage and deficient cognitive information processing during the late ERP stage in PD.     

Working memory function in post-traumatic stress disorder: An event-related potential study

ObjectivePrevious studies using event-related potentials (ERPs) in post-traumatic stress disorder (PTSD) have demonstrated reduced P3 amplitude during target detection and working memory (WM) processes. This study investigated effects of psychotropic medication (primarily antidepressants) on these ERP components.MethodsERPs were recorded from 26 scalp sites in 34 PTSD patients (20 unmedicated, 14 medicated) with age- and gender-matched controls during a WM paradigm that involved detection of target letters on a visual display.ResultsAs expected, PTSD patients showed a reduced amplitude P3wm component during WM updating and a reduced and delayed target P3 component. Contrary to expectation, these ERP effects were most apparent in the medicated subgroup of PTSD patients. The medicated PTSD subgroup showed a trend towards reduced P3wm amplitude compared with controls and a significant amplitude reduction and delay of target P3 component, while there was little difference between the non-medicated PTSD subgroup and controls. Neither ERP nor behavioural measures were related to Clinician Administered PTSD Scale (CAPS) symptom severity measures.ConclusionsThese results are consistent with research that suggests antidepressant medication may impair working memory performance.SignificanceThe present study illustrates the importance of monitoring medication effects on cognitive performance during clinical efficacy studies.     

Contribution of cognitive evoked potentials for detecting early cognitive disorders in multiple sclerosis

In Multiple Sclerosis (MS), one of the most frequent neurological diseases in young adults, cognitive dysfunctions have been under considered whereas their evolution may produce a fronto-sous-cortical deterioration and more than half of the MS patients present such dysfunctions. Nevertheless sensory evoked-potentials are classically used in this disease, event-related potentials (ERP) are not included in the clinical exploration of MS. Two studies are presented aimed at further tracking the usefulness of ERP for detecting early cognitive dysfunctions in MS. All of the patients presented a relapsing remitting MS for less than 5 years with a moderate physical handicap and complained from their memory. They performed a neuropsychological set and ERP were elicited using the oddball paradigm in both modalities, visual and auditory. In the first study, 10 patients without cognitive dysfunction at the neuropsychological evaluation and 10 patients with an attention deficit participated with 10 age-matched controls. In the second study, 10 patients with memory impairment at the neuropsychological evaluation and 10 age-matched controls were included. Our data argue for an earlier modification of ERP parameters in the visual modality than in the auditory one, even before the modification of cognitive scores. In both studies, P300 parameters were correlated to neuropsychological performances (and especially to the attention examination in the first study and to memory tests in the second study) in both modalities. Taking into account the clinical usefulness of ERPs, it is nowadays important to include this electrophysiological method in evaluation and follow-up of MS, and not only using the auditory modality but also the visual presentation in order to detect earlier cognitive dysfunctions even before modification of neuropsychological performances.