The continuing story of schizophrenia and schizoaffective disorder: One condition or two?

Although schizophrenia and schizoaffective disorder remain separable in diagnostic systems, the validity of the distinction is uncertain. This study asked whether schizophrenia and schizoaffective disorder are distinguishable on selected cognitive, social cognitive and structural social brain measures. Outpatients with a diagnosis of schizophrenia (n = 44) or schizoaffective disorder (n = 29) and non-psychiatric control participants (n = 62) were studied. Patients were assessed clinically (Positive and Negative Syndrome Scale) and all participants were administered a battery of cognitive (MATRICS Consensus Cognitive Battery; Wechsler Abbreviated Scale of Intelligence, Wide Range Achievement Reading) and social cognitive (Reading the Mind in the Eyes, Mayer-Salovey-Caruso Emotional Intelligence Test; MSCEIT) tasks. In addition, participants underwent structural magnetic resonance imaging (MRI) to yield cortical thickness data for 42 regions associated with the social brain network. Results showed no significant differences between patient groups on 17/18 cognitive/social cognitive and social brain cortical thickness measures. In contrast, schizophrenia and schizoaffective disorder patients differed from controls on 16/18 and 11/18 measures respectively. Schizoaffective disorder patients outperformed schizophrenia patients on an emotion regulation task (MSCEIT). Schizophrenia and schizoaffective disorder are largely indistinguishable on key cognitive, social cognitive and neural measures. The continuing separation of these syndromes in diagnostic systems and disease models requires is questionable and requires further attention.

Examining the effects of altered avatars on perception-action in virtual reality.

In virtual reality (VR), avatars are graphical representations of people. Previous research highlights benefits of having a self-avatar when perceiving-acting while embedded in a virtual environment. We studied the effect that an altered avatar had on the perception of one's action capabilities. In Experiment 1, some participants acted with a normal, or faithful, avatar whereas another group of participants used an avatar with an extended arm, all in virtual reality. Experiment 2 utilized the same methodology and procedure as Experiment 1, except that only a calibration phase occurred in VR, whereas other phases were completed in the real world. All participants performed reaches to various distances presented visually. Results showed that calibration to altered dimensions of avatars is possible after receiving feedback while acting with the altered avatar. Calibration occurred more quickly when feedback was used to transition from a normal avatar to an altered avatar than when transitioning from the altered avatar back to the normal avatar without feedback. The implications of these findings for training in virtual reality simulations and for transfer to the real world are discussed, along with the implications for the concept of an embodied action schema. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Calibration to tool use during visually-guided reaching.

In studying human perception and performance researchers must understand how the body schema is modified to accurately represent one's capabilities when tools are used, as humans use tools that alter their capabilities frequently. The present work tested the idea that calibration is responsible for modifying an embodied action schema during tool use. We investigated calibration in the context of manual activity in near space through a behavioral measure. Participants made blind reaches to various visual distances in pre- and post-test phases using a short tool that did not extend their reach. During an intervening calibration phase they received visual feedback about the accuracy of their reaches, with half of the participants reaching with a tool that extended their reach by 30cm. Results indicated both groups showed calibration appropriate to the type of tool that they used during the calibration phase, and this calibration carried over to reaches made in the post-test. These results inform discussions on the proposed embodied action schema and have applications to virtual reality, specifically the development of self-avatars.

Investigating haptic distance-to-break using linear and nonlinear materials in a simulated minimally invasive surgery task.

Accurate detection of mediated haptic information in minimally invasive surgery (MIS) is critical for applying appropriate force magnitudes onto soft tissue with the aim of minimising tissue trauma. Force perception in MIS is a dynamic process, with surgeons' administration of force into tissue revealing information about the remote surgical site which further informs the surgeons' haptic interactions. The relationship between applied force and material deformation rate provides biomechanical information specifying the deformation distance remaining until a tissue will fail: which is termed distance-to-break (DTB). The current study demonstrates that observers can detect DTB while deforming simulated tissues and stop before reaching the tissues' failure points. The design of training simulators, control devices and automated robotic systems for applications outside of MIS is discussed. Practitioner Summary: In MIS, haptic information is critical for applying appropriate forces onto soft tissue to minimise tissue trauma. Observers used force information to detect how far they could deform a virtual tissue before it would break. The design of training simulators, control devices and automated robotic systems is discussed.

Neurocognitive normality in schizophrenia revisited.

The validity and significance of normal range neurocognition in schizophrenia remain unclear and controversial. We assessed whether normal range patients and controls demonstrate evidence of decline relative to premorbid ability and differ in performance profiles across measures, including those external to the normality criterion. In addition, we compared below normal range healthy control participants with patients at the same ability level. Performance normality was defined as a MATRICS Consensus Cognitive Battery (MCCB) composite T score between 40 and 60. Patients (n = 17) and controls (n = 24) meeting the criterion were compared on MCCB domain scores and on independent measures of reading ability, probabilistic and social reasoning. Patients (n = 19) and controls (n = 20) scoring below 40 on the MCCB composite were compared on the same set of measures. Cognitively normal range patients and controls did not differ on estimated premorbid ability or decline and differed only on the Processing Speed domain of the MCCB. Performance did not differ across other domains or on social and probabilistic reasoning tasks. Cognitively below normal range patients and controls showed marked discrepancies between premorbid and current ability, but there were no group differences. In addition, below normal range groups did not differ on any MCCB domain score or in terms of external cognitive measures. Cognitively normal range schizophrenia patients may be largely indistinguishable from normal range controls, with the exception of processing speed performance. More typical schizophrenia patients below the normal range may be indistinguishable from low-performing controls even in terms of processing speed.

Stability and change in symptoms, cognition, and community outcome in schizophrenia.

It has been well established that neurocognitive deficits are a core feature in schizophrenia and predict difficulties in functional independence. However, few studies have assessed the longitudinal stability of cognition and key aspects of functional outcome concurrently. Even less attention has been directed at the contingency of cognitive change on real world outcome changes. Accordingly, this study will assess the extent to which significant changes in cognition and community status are independent or related. As a point of comparison, the stability of clinical symptom status and the relationship between symptom and outcome change are evaluated. Symptoms, cognitive abilities, and community outcome was assessed in 128 patients with schizophrenia at baseline and again one year later. Intraclass correlation coefficients were used to index stability and reliable change index analyses quantified the prevalence of significant improvement or deterioration in each of the three illness features. Results from these analyses revealed that symptom status, cognitive functioning, and community outcome are similarly stable in treated schizophrenia outpatients. A small proportion of the sample demonstrated significant improvement or deterioration in these domains, with only weak evidence that such change was predicted by changes in symptoms or cognition. Further, there was no strong evidence of a preferential relationship for cognition relative to symptoms in relation to functional outcome. These results shed light on the strength and nature of the cognition-real world outcome relationship in schizophrenia and have implications for pharmacological and behavioral interventions aimed at improving real world outcome.