Event-related potential correlates selectively reflect cognitive dysfunction in schizophrenics

Schizophrenics show event-related potential (ERP) and particularly P3 abnormalities. To study the more detailed relationships between these ERP alterations and cognitive dysfunction we recorded and analyzed ERPs using a particular experimental approach. In 34 schizophrenics and 25 controls ERPs were obtained by a visual Go/Nogo task requiring response inhibition and were decomposed into temporally independent topographical components using Independent Component Analysis (ICA). ICA disentangled different subcomponents of P3. Subcomponent P3b with a parietal maximum amplitude was significantly reduced in the schizophrenics, probably reflecting their attentional deficits. Subcomponent P3ng with a frontal maximum amplitude and enhanced during Nogo condition appeared as an electrophysiological index of response inhibition. A significantly reduced P3ng enhancement, found in schizophrenics, probably reflects their impaired response control.

CONCLUSIONS

ICA can successfully identify ERP subcomponents with distinct scalp topographies representing significant differential indices of normal and abnormal cognitive processing. Involvement of frontal brain areas in disturbed executive control in schizophrenics is supported by our ICA findings.

Antipsychotic efficacy of the antidepressant trimipramine: a randomized, double-blind comparison with the phenothiazine perazine

BACKGROUND

The tricyclic antidepressant trimipramine exhibits several features (e. g., dopaminergic effect, molecular structure similar to a neuroleptic, receptor-binding profile similar to clozapine) that suggest its potential as an antipsychotic medication. The aim of the study was to investigate the antipsychotic potential of trimipramine in a controlled clinical trial comparing its antipsychotic efficacy with that of a neuroleptic.

METHOD

In a German multi-center, randomized, double-blind trial, the antipsychotic efficacy of trimipramine was compared with that of the phenothiazine neuroleptic perazine, using the Brief Psychiatric Rating Scale (BPRS), the Positive and Negative Syndrome Scale (PANSS), and Clinical Global Impressions (CGI). Antidepressant efficacy of both agents was measured by use of the Bech-Rafaelsen Melancholia Scale (BRMES). Ninety-five patients with acute schizophrenia (DSM-III-R) and a BPRS total score > 40 at baseline were treated with either 300-400 mg trimipramine or 450-600 mg perazine for 5 weeks.

RESULTS

Therapeutic equivalence of both treatments (in the dosages used) could not be demonstrated (change in BPRS total score, per-protocol [PP] analysis, one-sided equivalence testing). However, intention-to-treat (ITT) as well as PP analysis showed a statistically significant decrease in the BPRS total scores in both treatment groups (PP: trimipramine, 56.5 +/- 9.8 to 44.1 +/- 17.9; perazine, 56.4 +/- 10.8 to 37.9 +/- 12.9). Significant decreases in all BPRS and PANSS subscores as well as CGI results and response rate support the antipsychotic efficacy of trimipramine. The BRMES total scores significantly decreased in both treatment groups without showing a significant difference between the two agents. Trimipramine was better tolerated than perazine and did not elicit extrapyramidal symptoms.

CONCLUSION

Trimipramine failed to exhibit therapeutic equivalence to perazine in the dosages used. However, there was evidence of a substantial antipsychotic effect of trimipramine. It may be a useful medication if depressive symptoms in psychotic patients require antidepressant treatment or if other antipsychotics cannot be administered.

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 the 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.

[Cognitive remediation. A new chance in rehabilitation of schizophrenic disorders?]

A critical review of current approaches and principles of cognitive remediation strategies in rehabilitation of schizophrenia is given. Selection of cognitive functions targeted in compensatory training programs could be based on results of neuropsychological predictor research on social and vocational functioning in community and neuropsychological rate limiting factors in rehabilitation. Methodological flaws in data base, missing of task analysis of more complex skills like social perception, social skills and interpersonal problem solving and the lack of evaluation of training generalization on work performance are discussed. Finally the cognitive remediation program developed in the Department of General Psychiatry and Psychotherapy/University of Freiburg, Germany is proposed. The components focused on training in attention, memory, and executive function (decision making, planning). Compensatory strategy building, and computer-mediated automatization are integrated in a group setting.

Some considerations on estimating event-related brain signals

Understanding the timing of mental acts is one of the prominent questions in information processing research. The analysis of event related potentials (ERP) with their high temporal resolution might make access to cognition related brain activity possible. We consider three major problems which make the application of ERPs questionable and then propose some solutions to these problems. The primary problem concerns the separation of the ERPs from the background EEG which is not related to the stimulus. The most common method used is averaging. We argue that this is not the most appropriate method and suggest an alternative for estimating the signal in single-trial recordings. Artifacts present a second problem. We will first review established methods of dealing with eye-movement artifacts and then propose an alternative. We will also report on current work on the parametrisation of single-trial signal estimates, which constitute the third problem considered.

[Cost-effectiveness of syphilis screening in a clinical for general psychiatry]

The most important clinical picture of syphilis for psychiatry is that of progressive paralysis. It is an organic psychosis with varying psychopathology. Therefore, nearly all patients in psychiatric departments undergo lues screening (TPHA) on admission. A cost-benefit analysis is presented. In the examination period from 1 January 1983 to 30 September 1988, in all 8915 patients were newly admitted to the department of general psychiatry at the University Hospital of Essen: 98 of these patients were TPHA-positive, and 6 patients had to be treated with antibiotics. One patient had neurolues. It seems therefore, that lues screening in a department of general psychiatry is performed for traditional reasons at high cost but with minimal benefit. The 6 patients who underwent a specific therapy were analysed; a catalogue of indication criteria for TPHA screening was elaborated and is presented.

[Drug treatment of schizophrenic psychoses in puerperium]

Three schizophrenic patients and one schizophreniform patient, all experiencing puerperal psychosis, required a drug-induced delactation (bromocriptine) simultaneously to neuroleptic treatment. Taking into account the pharmacodynamic effects, an exacerbation of symptoms following bromocriptine (a D-2 receptor agonist) and an impairment of delactation following neuroleptic treatment (bringing about the blockade of D-2 receptors) are to be expected. In three cases, we carried out a combined bromocriptine-haloperidol treatment and, in one case, a bromocriptine-clozapine treatment. The above mentioned complications were not observed in any of the cases. The problems which may result from using clozapine during the puerperal period are also discussed.

Altered fronto-central PINV topography and the primary negative syndrome in schizophrenia

Postimperative negative variation (PINV) was recorded during a warned reaction time paradigm in 16 chronic DSM-IIIR schizophrenics in remission. Clinical symptoms were assessed by BPRS, SANS and the anhedonia scale of the Chapman Questionnaire. Ten healthy controls were studied in the same manner. Over the fronto-central area we found a significantly elevated PINV amplitude with an altered topographical distribution in the patient group. The difference values 'PINV Cz-PINV Fz' were correlated negatively with primary negative symptoms of schizophrenia.

Postimperative negative variation and skin conductance response in chronic DSM-III-R schizophrenia

The hypothesis was tested that there are relationships between schizophrenic negative or deficit symptoms, the skin conductance nonresponding and an elevated amplitude of the postimperative negative variation (PINV). These variables were recorded in 16 chronic schizophrenics and 10 healthy controls. Clinical symptoms were assessed by the Brief Psychiatric Rating Scale, Scale for the Assessment of Negative Symptoms, Frankfurt Complaint Questionnaire 3 and Chapman Questionnaire. In the patient group we found a significantly elevated PINV at Fz. Surprisingly, only one patient was a skin conductance nonresponder. PINV amplitude at Fz and the number of skin conductance responses to habituation were not correlated with negative or deficit symptoms inclding anhedonia. The hypothesis thus had to be rejected.

Clinical and cerebral blood flow studies in patients with intracranial hemorrhage and amyloid angiopathy typical of Alzheimer's disease

Spontaneous intracerebral hemorrhages can occur in patients with severe amyloid angiopathy and other morphological signs of Alzheimer's disease (AD). We observed 15 patients in whom histological examination of brain tissue specimens obtained at surgery revealed characteristic congophilic amyloid deposits in subcortical arteries and/or nerve cells. Clinical follow-up examinations were carried out up to 9 years after diagnosis. In addition, three survivors from the operated group were investigated by neuropsychological testing and single photon emission computer tomography (SPECT) using Tc-99m-HMPAO for determination of regional cerebral blood flow (rCBF). SPECT could not differentiate between the "typical Alzheimer disease pattern" of bilateral temporo-parietal rCBF reduction and flow deficits resulting from previous hemorrhage. Intellectual functioning was found to be impaired to various degrees ranging from normal function to severe dementia (MMS test scores varied between 15 and 26 points); again, it was difficult to differentiate clinically between the nosologic entities mentioned above. On the basis of our present experience we cannot distinguish between brain dysfunction due to Alzheimer's disease and intracranial hemorrhage from amyloid angiopathy. This supports the idea that intracranial hemorrhage may only be one clinical manifestation of amyloid deposits, another one being "Alzheimer's disease" with varying preponderance.

[Optical hallucinations in the aged with diseases of the eye]

Two cases of Charles Bonnet Syndrome (CBS) showing an unusual history are reported. In a 67-year-old man visual hallucinations developed 38 years after bilateral optic nerve damage due to methyl alcohol poisoning. A 78-year-old woman suffering from bilateral advanced cataract experienced visual hallucinations which ceased after improvement of vision resulting from cataract extraction. Sensory deprivation and--possibly--central neurophysiological disturbance are to be regarded as important pathogenetic factors. Signs of cerebral dysfunction which could be relevant to the pathogenesis of CBS were revealed by the EEG.

Visual hallucinations in ophthalmology

Forty-three patients with severe visual impairment due to bilateral eye disease were assessed for visual hallucinations, 28 of them after eye surgery. Ages ranged between 65 and 93 years and none of the patients had any psychiatric disorder. Five of the 43 patients were diagnosed as cases with Charles Bonnet syndrome reporting visual hallucinations that had developed in the course of sight deterioration. There was strong indication that sensory deprivation was an essential pathogenetic factor for this phenomenon. Three of the 28 patients assessed following eye surgery who had no history of hallucinatory phenomena experienced visual hallucinations on the 2nd postoperative day without showing any other psychiatric symptoms. The various conditions associated with visual hallucinations are discussed that may be of relevance to the ophthalmologist.

Auditory brainstem response (ABR) in congenital central alveolar hypoventilation

Auditory brainstem responses (ABRs) were studied in a child with congenital central alveolar hypoventilation showing marked depression of respiratory drive during sleep. During wakefulness and normoventilation no ABR abnormalities were found, either at the age of 14 months or five years. ABR recordings during sleep at 14 months of age showed marked wave V latency and wave I to wave V interpeak latency prolongation of about 0.4 ms both for periods of hypoventilation and normoxic hypercapnia. ABR findings of this and other studies carried out in sleep apneas are discussed with respect to brainstem dysfunction associated with varied sleep apnea syndromes.

Clinical application of event related potentials in patients with brain tumours and traumatic head injuries

Event related potential recording and psychometric evaluation of cognitive impairment were carried out on 21 patients with brain tumours, 21 patients with severe head injuries and 24 controls. The tumour and trauma patients who met the psychometric inclusion criteria for dementia, but not the non-demented patients, had significantly longer N2 and P3 latencies than the controls. In assessing individual patients P3 latency correctly differentiated between demented and non-demented patients in 81% of cases (for N2 latency 77%). Particularly P3 latency may provide a practical and objective measure of mental impairment in neurosurgical disorders producing dementia. Marked asymmetry in N2 and P3 amplitudes between hemispheres was observed in a number of cases. No significant relationship was found between diminution of N2 and P3 components and side of lesion.

Evoked potential assessment of mental function during recovery from severe head injury

Event-related potential recording and neuropsychologic testing were carried out on 18 severely head-injured patients and on a control group. At early stages of injury the patients had prolonged P3 latencies and reduced psychometric scores. In the assessment of individual patients the P3 latency proved to be a measure that diagnosed cognitive impairment with clinically acceptable levels of accurate classification. On retesting 4.6 +/- 1.6 months after trauma, normal values were found for the neuropsychologic measures and a residual latency prolongation for P3, indicating the P3 latency to be a sensitive index of subtle residual brain dysfunction due to head injury.

[Event-related brain potentials and intellectual impairment--a study in patients with brain tumor and craniocerebral trauma]

Event-related potential recording (component N1, P2, N2, and P3) and neuropsychological assessment of cognitive impairment were carried out on 15 patients with brain tumour, 15 patients with severe head injury and 24 controls. The tumour and trauma patients had significantly lower psychological test scores, smaller N1 amplitudes and longer N2 and P3 latencies than normals. For the tumour and trauma patients significant correlations were found between N2 and P3 latency and the Mini-Mental State test and memory tests. For individual patients abnormally increased N2 and P3 latency was found to occur in association with abnormally reduced neuropsychological test scores. N2 and P3 latency proved the only electrophysiological variables examined which provided a measure of cerebral functioning correlating with the psychometric variables. N2 and P3 latency may be regarded as a useful diagnostic test for cognitive impairment especially in patients with motor handicaps, to whom neuropsychological tests cannot be administered.

[Regulation of respiration during sleep in congenital central sleep apnea]

We report on 2 children aged 13 and 14 months with congenital central alveolar sleep apnea which showed depression of respiratory drive during sleep resulting from dysfunction of central chemoreceptors. Hypoventilation was found to be more severe during NREM sleep (minimum of alveolar ventilation in stages 3/4) than during REM sleep. During NREM sleep arousal responses to hypoxia proved to be an important factor in influencing the level of alveolar ventilation and in preventing fatal asphyxia.