These findings confirm the existence of early-stage visual processing dysfunction in schizophrenia and provide the first evidence that such deficits are due to decreased nonlinear signal amplification, consistent with glutamatergic theories. Neuroimaging studies support the hypothesis of dysfunction within low-level visual pathways involving thalamocortical radiations. Deficits in early-stage visual processing significantly predict higher cognitive deficits.

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Cognitive remediation is now widely recognized as an effective treatment for cognitive deficits in schizophrenia. Its effects are meaningful, durable, and related to improvements in everyday functional outcomes. As with many therapies, the evolution of cognitive remediation has resulted in treatment programs that use a variety of specific techniques, yet share common core principles. This paper is the product of a cognitive remediation expert working group consensus meeting to identify core features of the treatment and produce recommendations for its design, conduct, reporting, and implementation. Four techniques were identified as core features of cognitive remediation: facilitation by a therapist, cognitive exercise, procedures to develop problem-solving strategies, and procedures to facilitate transfer to real world functioning. Treatment techniques within each of these core features are presented to facilitate decisions for clinical trials and implementation in clinical settings.

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

The deficit syndrome is thought to characterize a pathophysiologically distinct subgroup of patients with schizophrenia. Supporting this notion, prior research examining the neuropsychological correlates of the deficit syndrome has suggested the presence of a differential impairment in frontal and parietal functions. This article reports findings from 2 studies attempting to replicate and extend previous reports of a differential neuropsychological impairment in deficit schizophrenia. In the first study, we administered a comprehensive neuropsychological battery to 20 deficit and 25 nondeficit patients with schizophrenia and 25 normal healthy controls. In the second study, a meta-analysis was conducted of 13 separate studies examining the neuropsychology of the deficit syndrome. There was little evidence from either of the present studies that the deficit syndrome is associated with a selective impairment in frontal and parietal lobe functions. The first study failed to find significant differences in frontal or parietal abilities for deficit vs nondeficit patients. The meta-analytic findings revealed that deficit patients were globally more neuropsychologically impaired than nondeficit patients (effect size [ES] = 0.41). Relative to nondeficit patients, deficit patients performed poorest on tests of olfaction (ES = 1.11), social cognition (ES = 0.56), global cognition (ES = 0.52), and language (ES = 0.51). The neuropsychological impairments associated with the deficit form of schizophrenia do not follow an obvious anatomically defined pattern of impairment. The question of whether deficit patients exhibit a unique cognitive impairment profile will require a more sophisticated and rigorous examination of the neuropsychology of the deficit syndrome.