Psychophysiological correlates of social skills deficits in persons with schizophrenia

A Reliable and Valid Assessment of Sustained Attention for Patients With Schizophrenia: The Computerized Digit Vigilance Test

Objective

The purposes of this study were to examine the test-retest reliability, concurrent validity, and ecological validity of the Computerized Digit Vigilance Test (C-DVT) in patients with schizophrenia.

Method

Each participant was assessed four times, with 1-week intervals. In each assessment, the participants completed both the C-DVT and the original DVT. The participants were also assessed using the Lawton Instrumental Activities of Daily Living Scale (LIADL) and the Personal and Social Performance Scale (PSP).

Results

Forty-nine participants were recruited in this study. The results showed that the test-retest agreement of the C-DVT was good-to-excellent (intraclass correlation coefficient = 0.71-0.89). The random measurement errors of the C-DVT were acceptable (percentages of minimal detectable change = 12.9%-24.1%). The practice effect of the C-DVT reached a plateau after three assessments (effect size <0.20). The concurrent validity of the C-DVT was good (r = .75-.79 with DVT) when we controlled for the randomized administration order of the two tests. The ecological validity of the C-DVT was good (r = -.44 with the LIADL; r = -.45 with the PSP).

Conclusions

The C-DVT had acceptable test-retest reliability, sound concurrent validity, and sound ecological validity in patients with schizophrenia. These findings indicate that the C-DVT has the potential to be a reliable and valid test of sustained attention in patients with schizophrenia.

Subjective Stress, Salivary Cortisol, and Electrophysiological Responses to Psychological Stress

The present study aimed to investigate the subjective stress, salivary cortisol, and electrophysiological responses to psychological stress induced by a modified version of a mental arithmetic task. Fifteen participants were asked to estimate whether the multiplication product of two-decimal numbers was above 10 or not either with a time limit (the stress condition) or without a time limit (the control condition). The results showed that participants reported higher levels of stress, anxiety, and negative affect in the stress condition than they did in the control condition. Moreover, the salivary cortisol level continued to increase after the stress condition but exhibited a sharp decrease after the control condition. In addition, the electrophysiological data showed that the amplitude of the frontal-central N1 component was larger for the stress condition than it was for the control condition, while the amplitude of the frontal-central P2 component was larger for the control condition than it was for the stress condition. Our study suggests that the psychological stress characteristics of time pressure and social-evaluative threat caused dissociable effects on perception and on the subsequent attentional resource allocation of visual information.

Reduced frontopolar activation during verbal fluency task in schizophrenia: a multi-channel near-infrared spectroscopy study

Functional neuroimaging studies to date have shown prefrontal dysfunction during executive tasks in schizophrenia. However, relationships between hemodynamic response in prefrontal sub-regions and clinical characteristics have been unclear. The objective of this study is to evaluate prefrontal hemodynamic response related to an executive task in schizophrenia and to assess the relationship between activation in the prefrontal sub-regions and clinical status. Fifty-five subjects with schizophrenia and age- and gender-matched 70 healthy subjects were recruited for this case-control study in a medical school affiliated hospital in the Tokyo metropolitan area, Japan. We measured hemoglobin concentration changes in the prefrontal (dorsolateral, ventrolateral, and frontopolar regions) and superior temporal cortical surface area during verbal fluency test using 52-channel near-infrared spectroscopy, which enables real-time monitoring of cerebral blood volumes in the cortical surface area under a more restraint-free environment than positron emission tomography or functional magnetic resonance imaging. The two groups showed distinct spatiotemporal pattern of oxy-hemoglobin concentration change during verbal fluency test. Schizophrenia patients were associated with slower and reduced increase in prefrontal activation than healthy controls. In particular, reduced activations of the frontopolar region, rather than lateral prefrontal or superior temporal regions, showed significant positive correlations with lower global assessment of functioning scores in the patient group, although task performance was not significantly associated with the scores. These results suggest that reduced frontopolar cortical activation is associated with functional impairment in patients with schizophrenia and that near-infrared spectroscopy may be an efficient clinical tool for monitoring these characteristics.

Phonetic mismatch negativity predicts social skills acquisition in schizophrenia

Neurobiological mechanisms for social skills acquisition in schizophrenia remain largely unknown. We investigated whether an electrophysiological index of cognitive function predicts the degree of training-related social skills improvement in schizophrenia. Thirteen patients with schizophrenia underwent assessment of mismatch negativity (MMN) event-related potentials, followed by participation in a 3-month social skills training. Larger right frontal/temporal MMN current density values elicited by across-phoneme change were significantly associated with individual degrees of improvement in total social skills scores as assessed by a structured role play test. Although preliminary, these results suggest that phonetic MMN could be an index of social skills acquisition in patients with schizophrenia.

A new dimension of sensory dysfunction: stereopsis deficits in schizophrenia

BACKGROUND

Schizophrenia is a neurocognitive disorder with a wide range of cognitive and sensory impairments. Early visual processing has been shown to be especially impaired. This article investigates the integrity of binocular depth perception (stereopsis) in schizophrenia.

METHODS

Seventeen schizophrenia patients and 19 healthy control subjects were compared on the Graded Circles Stereo Test. Results of stereoacuity were compared between patients and control subjects using t test.

RESULTS

Schizophrenia patients demonstrated significantly (p = .006) reduced stereoacuity (mean = 142 arcseconds) versus control subjects (mean = 55 arcseconds). At the normative level for adults, patients performed below chance.

CONCLUSIONS

These findings demonstrate an impairment of binocular depth perception and further confirm deficits of early visual processing in schizophrenia. Findings are discussed in context of magnocellular/dorsal stream processing with implications for visual processing and cognitive deficits.

Attentional dysfunction, social perception, and social competence: what is the nature of the relationship?

The aim of this study was to examine the nature of the relationship between attentional dysfunction and social competence deficits in patients with schizophrenia. Attentional functioning, social perception, and social competence were assessed in 56 inpatients. Measures of vigilance and span of apprehension were administered to assess attentional functioning. Social perception was assessed with an audiovisual measure of affect recognition. Social competence was rated from a role-play task. Span of apprehension and auditory vigilance emerged as specific predictors of social competence. Affect recognition was tested as a mediator and a moderator of the relationship between attentional dysfunction and social competence. Affect recognition was found to moderate the relationship between span of apprehension and social competence.

Procedural memory predicts social skills in persons with schizophrenia

Despite a growing number of studies that have investigated the relationship between neurocognition and psychosocial outcome in schizophrenia, no studies have looked at the relationship between procedural memory and social skills measures in schizophrenia. The goal of this study was to investigate whether procedural memory, often preserved in schizophrenia, could predict nonverbal social skills in chronic patients with schizophrenia. Fourteen outpatients with schizophrenia participated in our study. Procedural memory was evaluated using the Mirror Reading Test, and nonverbal and verbal social skills were evaluated using a structured role play test. As predicted, there was a significant positive correlation between the learning index of the Mirror Reading Test and nonverbal skills (Spearman rho=0.559, p = 0.038), but not for verbal communication skills or processing skills. Although preliminary, these results provide the first evidence of an association between procedural memory and nonverbal social skills in patients with schizophrenia.

Impairments in generation of early-stage transient visual evoked potentials to magno- and parvocellular-selective stimuli in schizophrenia

OBJECTIVE

Patients with schizophrenia demonstrate significant impairments of early visual processing, potentially implicating dysfunction of the magnocellular visual pathway. The present study evaluates transient visual evoked potential (tVEP) responses to stimuli biased toward the magnocellular (M) or parvocellular (P) systems in patients with schizophrenia vs. normal volunteers first to evaluate relative contributions of M and P systems to specific tVEP components in schizophrenia and, second, to evaluate integrity of early M and P processing in schizophrenia.

METHODS

Seventy-four patients with schizophrenia and schizoaffective disorder were compared with 59 control subjects using separate stimuli to assess the tVEP response to M, P and mixed M/P conditions. Stimuli were biased toward M vs. P processing by manipulation of chromatic and achromatic contrast. C1, P1, N1 and P2 components were compared between patients and controls. All subjects showed 20/32 vision or better.

RESULTS

Waveforms were obtained to low contrast (M), chromatic contrast (P) and high contrast (mixed M/P) stimuli in both patients and controls. C1 was present to P and mixed M/P stimuli. Patients showed a significant reduction in amplitude and an increase in latency of the C1 component. P1 was elicited primarily by M and mixed M/P stimuli, whereas N1 was elicited primarily by P and mixed M/P stimuli. Patients showed reductions in both P1 and N1 amplitudes across conditions. However, only reductions in P1 amplitude survived covariation for between group differences in visual acuity. Further, P1 amplitude reductions in the M condition correlated with a proxy measure of global outcome.

CONCLUSIONS

M- and P-selective stimuli elicit differential components of the tVEP. Patients with schizophrenia show significant reductions in response even to simple visual stimuli. Deficits, particularly within the M system, may correlate significantly with global outcome and level of community functioning.

SIGNIFICANCE

Whereas deficits in high-order cognitive processing have been extensively documented in schizophrenia, integrity of early-stage sensory processing has been studied to a lesser degree. The present findings suggest that deficits in early-stage visual processing are significantly related to overall clinical outcome in schizophrenia. Further, between-group differences in visual acuity may influence VEP results, even for subjects with 'normal' vision (20/32 or better).

Social cognitive problem-solving in schizophrenia: associations with fluency and verbal memory

This study assessed the relationship between social functioning and neurocognitive function in individuals with schizophrenia. Social cognitive problem-solving (SCPS) is a significant contributor to social competence and is an aspect of information processing that is involved in the identification and resolution of interpersonal or social problems. We examined 49 schizophrenia patients and 28 healthy controls using the means-ends problem-solving procedure (MEPS) for SCPS, the Rey Auditory Verbal Learning Test (RAVLT), the Wisconsin Card Sorting Test (WCST), and a series of fluency tests for neurocognitive assessment, as well as the Positive and Negative Syndrome Scale (PANSS) and the Global Assessment of Functioning (GAF). Fluency tests can be used to evaluate divergent thinking, and a qualitative analysis was done of the fluency test responses. The results suggest that patients with schizophrenia have a significantly poorer MEPS performance than normal controls. In patients with normal RAVLT scores, MEPS scores were correlated with task-modified responses on the fluency test but not with any of the WCST scores. This suggests that SCPS is related to divergent thinking that requires concept flexibility and/or the conversion of viewpoint in patients with schizophrenia in whom verbal memory function is preserved.

Electrophysiological indices associated with social functioning outcome in schizophrenia: a 5-year follow-up study

We previously demonstrated that event-related potentials (ERPs), such as N1/N2b amplitudes in an auditory selective attention task, were significantly associated with communication skills of schizophrenia. The present study investigated the relationship between N1/N2b amplitudes and the quality of life (QOL) 5 years after ERP measurement. QOL of 15 patients with schizophrenia was assessed using the quality of life scale (QLS). Correlational analyses revealed a significant relationship between N2b, but not N1, amplitude and specific domains of QOL. N2b amplitude, an electrophysiological index of orienting response, may be associated with longitudinal social functioning outcome in schizophrenia.

Psychophysiological index during auditory selective attention correlates with visual continuous performance test sensitivity in normal adults

The continuous performance test (CPT) provides a reliable index of cognitive function, but it is still unclear what aspects of processing this test measures. This study aimed to investigate the contribution of different aspects of cognitive function to the performance on degraded stimulus CPT (DSCPT), which requires a higher level of mental effort than the conventional CPT. Event-related potential (ERP) components, MMN, N2b, and early and late Nds were measured at 16 electrode sites in 19 right-handed normal volunteers using an auditory selective attention task. The association between CPT sensitivity ratings (sensitivity A') and amplitudes of each component was examined for each electrode site. The CPT sensitivity A' showed a significant positive correlation with the N2b amplitude in the fronto-central and temporal regions, predominantly in the right hemisphere and specifically to the right ear of stimulation. This finding suggests that the controlled deviance detection process was related to DSCPT performance.

Neuroanatomy and neurophysiology in schizophrenia

Schizophrenia is a major mental disorder, characterized by their set of symptoms, including hallucinatory-delusional symptoms, thought disorder, emotional flattening, and social withdrawal. Since 1980s, advances in neuroimaging and neurophysiological techniques have provided tremendous merits for investigations into schizophrenia as a brain disorder. In this article, we first overviewed neuroanatomical studies using structural magnetic resonance imaging (s-MRI), MR spectroscopy (MRS), and postmortem brains, followed by neurophysiological studies using event-related potentials (ERPs) and magnetoencephalography (MEG), in patients with schizophrenia. Evidences from these studies suggest that schizophrenia is a chronic brain disorder, structurally and functionally affecting various cortical and subcortical regions involved in cognitive, emotional, and motivational aspects of human behavior. Second, we reviewed recent investigations into neurobiological basis for schizophrenic symptoms (auditory hallucinations and thought disorder) using these indices as well as hemodynamic assessments such as positron emission tomography (PET) and functional MRI (f-MRI). Finally, we addressed the issue of the heterogeneity of schizophrenia from the neurobiological perspective, in relation to the neuroanatomical and neurophysiological measures.