Recent Studies of Psychophysiology in Schizophrenia

Holzman, Philip S.

doi:10.1093/schbul/13.1.49

Cited by 217 publications

(102 citation statements)

References 146 publications

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“…Abnormalities in smooth pursuit are commonly found in patients with schizophrenia and are attributed, by some workers, to the presence of global attentional and inhibitory dysfunction. 23,27,28 This attribution is supported by the observation that SPEM abnormalities can be reversed in schizophrenic patients, to a degree, by attention-enhancing techniques, and by the fact that at least one of the pathological components of SPEM performance, task-inappropriate intrusion of anticipatory saccades, has been conceptualized as a failure of inhibitory control. 29,30 However, the role of attentional and inhibitory dysfunction in the genesis of smooth pursuit abnormalities has been questioned, because adults with attention-deficit/hyperactivity syndrome do not exhibit pursuit abnormalities.…”

Section: Discussionmentioning

confidence: 95%

Disruption of smooth pursuit eye movements in cirrhosis: Relationship to hepatic encephalopathy and its treatment

et al. 2005

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Smooth pursuit eye movements (SPEM) are the conjugate movements used to track the smooth trajectory of small dots. Jerky or 'saccadic' ocular pursuit has been reported in patients with cirrhosis, but no formal assessment of SPEM has ever been undertaken. The aim of this study was to evaluate SPEM in patients with cirrhosis and varying degrees of hepatic encephalopathy. The patient population comprised 56 individuals (31 men, 25 women) of mean age 51.1 (range, 25-70) years, with biopsy-proven cirrhosis, classified, using clinical, electroencephalographic, and psychometric variables, as either neuropsychiatrically unimpaired or as having minimal or overt hepatic encephalopathy; patients were further categorized in relation to their treatment status. The reference population comprised 28 healthy volunteers (12 men, 16 women) of mean age 47.3 (range, 26-65) years. SPEM was assessed using an electro-oculographic technique. Visual inspection of the SPEM recordings showed clear disruption of smooth pursuit in the patients with minimal hepatic encephalopathy, and more pronounced disruption, if not complete loss, of smooth pursuit in patients with overt hepatic encephalopathy. The differences observed in quantifiable SPEM indices between the healthy volunteers/unimpaired patients and those with overt hepatic encephalopathy were significant (P < .05). In conclusion, SPEM performance is impaired in patients with hepatic encephalopathy in parallel with the degree of neuropsychiatric disturbance: the pathophysiology of these changes is unknown, but retinal, extrapyramidal, and attentional abnormalities are likely to play a role. Treatment status confounds the classification of neuropsychiatric status and should be taken into account when categorizing these patients. (HEPATOLOGY 2005;42:772-781.)

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Section: Discussionmentioning

confidence: 95%

Disruption of smooth pursuit eye movements in cirrhosis: Relationship to hepatic encephalopathy and its treatment

et al. 2005

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“…The problems in selective attention, veridical perception of novel stimuli, and disturbed thought processes characteristic of schizophrenia make the P3 a useful probe of information processing in schizophrenics. The demonstration that schizophrenics show an overall decrement in auditory-evoked P3 amplitude relative to controls remains one of the most replicable ERP findings in psychiatry (see Begleiter & Porjesz, 1986;Holzman, 1987;Pritchard, 1986;Roth, 1977, for review).…”

Section: Descriptorsmentioning

confidence: 99%

Parametric manipulations of auditory stimuli differentially affect P3 amplitude in schizophrenics and controls

et al. 1994

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Schizophrenics show P3 amplitude reduction and topographic asymmetries. It is unclear whether the underlying cause of these deficits is primarily functional or structural. This study examined the effect of stimulus discriminability and task instruction on behavioral performance and P3 in schizophrenics and normal control subjects. Stimulus discriminability was manipulated by varying the overall loudness and pitch disparity of the two tones in an auditory oddball paradigm. Instructions emphasized either speed or accuracy of response. Instructions had no significant effects on reaction time, perceptual sensitivity, response bias, or P3. With increased discriminability, however, both groups improved in mean reaction time to targets and perceptual sensitivity. In controls, P3 became earlier and larger with increased stimulus discriminability and was consistently larger over left temporal areas than over right temporal areas. In schizophrenics, P3 latency was related to stimulus discriminability, but amplitude was not; P3 amplitude did not increase with improvement of perceptual sensitivity and reaction time. Unlike normal controls, schizophrenics had a P3 asymmetry at temporal sites, with reduced left-sided voltages. The results are not consistent with a primarily functional cause of P3 aberrations in schizophrenia and are compatible with the hypothesis that P3 amplitude deficits in schizophrenia are related to underlying pathophysiology of temporal lobe generator sites. DescriptorsEvent-related potentials; P3; Scalp asymmetry; Schizophrenia; Stimulus parametersThe association of the P3 event-related potential (ERP) with selective attention and processing of novel stimuli is well established (e.g., Donchin, Karis, Bashore, Coles, & Gratton, 1986;Hillyard, Hink, Schwent, & Picton, 1973;Isreal, Wickens, & Donchin, 1979;Squires, Squires, & Hillyard, 1975). The problems in selective attention, veridical perception of novel stimuli, and disturbed thought processes characteristic of schizophrenia make the P3 a useful probe of information processing in schizophrenics. The demonstration that schizophrenics show an overall decrement in auditory-evoked P3 amplitude relative to controls remains one of the most replicable ERP findings in psychiatry (see Begleiter & Porjesz, 1986;Holzman, 1987;Pritchard, 1986;Roth, 1977, for review).The relative contributions of functional and structural deficits to the voltage reduction in P3 amplitude in schizophrenics remains unclear. Functionally, auditory P3 amplitude varies with Copyright © 1994 (e.g., Polich, 1987). The decrement observed in schizophrenics may be due to lowered sensitivity and performance in comparison with control subjects, with little involvement of the neural substrate of P3. That is, schizophrenics' P3 responses to stimuli in standard oddball tasks may be morphologically similar to those of controls in conditions where stimuli are not easily discriminable. A greater degree of equivocation in stimulus analysis could lead to smaller P3 amplitudes (Ruchkin & S...

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“…see reviews [23][24][25][26]. As reviewed below, we chose the Continuous Performance test (CPT) as the task during FDG uptake because of its (1) demonstrated sensitivity to patient attentional deficits; (2) its continued impairment in clinically remitted patients; (3) its relationship to risk for developing the illness, and (4) its well-studied psycho metric properties.…”

Section: Introductionmentioning

confidence: 99%

Correlational Patterns of Cerebral Glucose Metabolism in Never-Medicated Schizophrenics

et al. 1996

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We studied 18 never-medicated schizophrenic patients and 22 normal control subjects with ¹⁸F-deoxyglucose (FDG) positron emission tomography. Patients and controls performed the continuous performance test during FDG uptake. Cortical and subcortical structures comprising two circuits selected on the basis of several theoretical models of schizophrenia were examined. The correlation of glucose metabolic rate (GMR) for each structure in each circuit with connected structures was calculated and tested for two-tailed significance. Schizophrenics showed significantly different patterns of intercorrela-tions for both circuits. The largest difference was in the correlation of GMR in the anterior thalamus with the frontal cortex, a key element in the thalamo-cortical-striatal circuit suggested to be abnormal in some models of schizophrenia. Correlations of the frontal lobe with other regions were also more positive in normal controls than schizophrenics; controls had three correlational paths from the frontal cortex (to temporal cortex, ventral anterior thalamus, and dorsal medial thalamus) with significantly more positive correlations than schizophrenics, perhaps consistent with other findings of frontal cortical dysfunction in schizophrenia. Normal controls also had both more significant positive and more significant negative correlations between the occipital cortex and other brain areas than schizophrenics. Correlations between homologous areas in the right and left hemispheres were prominent in both groups.

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Recent Studies of Psychophysiology in Schizophrenia

Cited by 217 publications

References 146 publications

Disruption of smooth pursuit eye movements in cirrhosis: Relationship to hepatic encephalopathy and its treatment

Disruption of smooth pursuit eye movements in cirrhosis: Relationship to hepatic encephalopathy and its treatment

Parametric manipulations of auditory stimuli differentially affect P3 amplitude in schizophrenics and controls

Correlational Patterns of Cerebral Glucose Metabolism in Never-Medicated Schizophrenics

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