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S F Faux

Publications and source records attributed to S F Faux.

28 records · Page 2Linked to original sources
PubMed1985

Long-latency event-related potentials in the evaluation of cognitive function in children.

The endogenous auditory P300 event-related potential (P3) has been used to differentiate functional and organic cognitive disorders in adults. We found that children with organic cognitive impairments (as determined by the Halstead-Reitan [HR] test) had greater P3 latencies than children with normal HR evaluations. The P3 and HR showed 85% agreement in independent assessments of functional or organically based cognitive impairment in children. Mini-Mental-State, IQ, EEG evaluations, and clinical suspicions of "organicity" with respect to cognitive function were similarly associated with P3 latency.

Adolescent↗
PubMedDate not supplied

The auditory N2 component in schizophrenia: relationship to MRI temporal lobe gray matter and to other ERP abnormalities.

The N2 component of the auditory event-related potential (ERP) indexes cognitive processes involved in the categorization of deviant stimuli. Although N2 amplitude and latency abnormalities have been reported in schizophrenia, their relationship to MRI structural changes, clinical status, and P3 abnormalities has not been defined. We therefore studied the auditory N2 and P3 components elicited by an oddball paradigm in 15 right-handed male subjects with schizophrenia and 14 control subjects who had quantitative MRI measures of temporal lobe gray-matter structures. To provide a methodological comparison, we measured the auditory N2 from both the target ERP (N2t) and the target-minus-frequent ERP difference (N2d) waveforms. Both N2t and N2d amplitude were bilaterally reduced in schizophrenics, with N2d showing a more pronounced reduction. Within the schizophrenic group, N2 amplitude reduction was associated with reduction in gray-matter volume of the left superior temporal gyrus (STG) and of medial temporal lobe structures bilaterally, and clinically, with greater chronicity. P3 amplitude, in contrast, correlated only with left posterior STG volume, and was more prominently associated with delusions and thought disorder. These findings suggest that the N2 and P3 components, though occurring sequentially in the ERP, tap separable anatomic and behavioral abnormalities in schizophrenia.

Adult↗
PubMedDate not supplied

Reversed temporal region asymmetries of P300 topography in left- and right-handed schizophrenic subjects.

The auditory P300 evoked potential was recorded in 36 subjects: left- (LH) and right-handed (RH) schizophrenic males and LH and RH normal controls. LH and RH normals showed no asymmetry in P300 scalp topography. LH and RH schizophrenics, however, showed lateralized asymmetries in temporal scalp regions: left < right P300 voltage asymmetry in RH schizophrenics and left > right P300 voltage asymmetry in LH schizophrenics. These data suggest that the schizophrenic pathology of P300 neural generators is lateralized according to handedness and provide the first evidence that LH and RH schizophrenics can be dissociated based on left-right voltage asymmetries in P300 topography. These findings further emphasize the need for control of handedness in P300 studies of schizophrenia.

Acoustic Stimulation↗
PubMedDate not supplied

P300 topographic asymmetries are present in unmedicated schizophrenics.

Our laboratory has repeatedly found a left < right auditory P300 temporal lobe topographic asymmetry in right-handed, medicated schizophrenics. To determine whether this asymmetry was attributable to the effects of antipsychotic medications, we collected auditory "odd-ball" P300 event-related potentials from 14 right-handed, unmedicated schizophrenics (withdrawn from medication for an average of 21 days) and 14 right-handed, normal controls. Analysis of normalized P300 amplitudes showed a statistically significant difference in the voltage distributions between groups (a group by temporal electrode site interaction) that was consistent with a left < right temporal voltage asymmetry in schizophrenics but not in the normal controls. We conclude that P300 topographic asymmetries are present in unmedicated schizophrenics. These data are compatible with the growing body of data suggesting left temporal lobe structural abnormalities in schizophrenia.

Acoustic Stimulation↗
PubMedDate not supplied

Measurement of visual sustained attention in schizophrenia using signal detection analysis and a newly developed computerized CPT task.

Sustained attention in schizophrenia was assessed with a newly developed, computer-controlled, modified version of the continuous performance test in which specific attentional effects can be empirically distinguished from nonspecific factors by signal detection theory (SDT). Results indicated that patients showed a more rapid decline in specific attentional, but not nonspecific processes, as measured by SDT parameters of A' and B", respectively.

Adult↗
PubMedDate not supplied

Event-related potentials in schizophrenia: their biological and clinical correlates and a new model of schizophrenic pathophysiology.

Evidence is growing that schizophrenic patients show significant structural damage in the temporal lobe limbic system. We review event-related potentials abnormalities (ERPs) in schizophrenia that may be related to dysfunction in this brain region or its inputs; ERPs discussed include the N100/P200, P300 and N400 components. Additional CT and clinical data have led our laboratory to a unifying working hypothesis of the presence of temporal lobe damage in schizophrenics that is evinced electrophysiologically as ERP alterations, structurally as tissue loss/derangement, and clinically as positive symptoms. The final section of this paper presents a new model of at least one form of schizophrenic pathology that, while speculative, incorporates experimentally based data from both our ERP work and from basic cellular physiology and pharmacology. The model proposes that positive symptoms of schizophrenia are related to limbic system pathology and in particular to a dysregulation of the NMDA form of excitatory amino acid transmission, potentiated by stress, and leading to cell damage and death due to 'excitotoxicity'.

Arousal↗
PubMedDate not supplied

Temporal lobe abnormalities in a patient with schizophrenia who has word-finding difficulty: use of high-resolution magnetic resonance imaging and auditory P300 event-related potentials.

Postmortem, magnetic resonance, and event-related potential studies suggest the presence of temporal lobe abnormalities in schizophrenia. Analyses using convergent measurements of brain structure and function, however, have rarely been done in the same patients. We recently developed a protocol using high-spatial-resolution magnetic resonance scans, auditory P300 event-related potentials, and thought disorder scales to examine temporal lobe structure and function in the same patients. We report a case of schizophrenia that showed left-lateralized volume reduction in the superior temporal gyrus, hippocampus, and parahippocampal gyrus (also on right), with associated P300 amplitude reduction and thought disorder marked by word-finding difficulties and perseverations.

Anomia↗