Perception of causality in schizophrenia spectrum disorder

Patients with schizophrenia spectrum disorders often maintain deviating views on cause-effect relationships, especially when positive and disorganization symptoms are manifest. Altered perceived causality is prominent in delusional ideation, in ideas of reference, and in the mentalizing ability (theory of mind [ToM]) of patients. Perceiving causal relationships may be understood either as higher order cognitive reasoning or as low-level information processing. In the present study, perception of causality was investigated as a low-level, preattentional capability similar to gestalt-like perceptual organization. Thirty-one patients (24 men and 7 women with mean age 27.7 years) and the same number of healthy control subjects matched to patients with respect to age and sex were tested. A visual paradigm was used in which 2 identical discs move, from opposite sides of a monitor, steadily toward and then past one another. Their coincidence generates an ambiguous, bistable percept (discs either "stream through" or "bounce off" one another). The bouncing perception, ie, perceived causality, is enhanced when auditory stimuli are presented at the time of coincidence. Psychopathology was measured using the Positive and Negative Syndrome Scale. It was found that positive symptoms were strongly associated with increased perceived causality and disorganization with attenuated perceived causality. Patients in general were not significantly different from controls, but symptom subgroups showed specifically altered perceived causality. Perceived causality as a basic preattentional process may contribute to higher order cognitive alterations and ToM deficiencies. It is suggested that cognitive remediation therapy should address both increased and reduced perception of causality.

Altered perception of apparent motion in schizophrenia spectrum disorder

Apparent motion (AM), the Gestalt perception of motion in the absence of physical motion, was used to study perceptual organization and neurocognitive binding in schizophrenia. Associations between AM perception and psychopathology as well as meaningful subgroups were sought. Circular and stroboscopic AM stimuli were presented to 68 schizophrenia spectrum patients and healthy participants. Psychopathology was measured using the Positive and Negative Syndrome Scale (PANSS). Psychopathology was related to AM perception differentially: Positive and disorganization symptoms were linked to reduced gestalt stability; negative symptoms, excitement and depression had opposite regression weights. Dimensions of psychopathology thus have opposing effects on gestalt perception. It was generally found that AM perception was closely associated with psychopathology. No difference existed between patients and controls, but two latent classes were found. Class A members who had low levels of AM stability made up the majority of inpatients and control subjects; such participants were generally young and male, with short reaction times. Class B typically contained outpatients and some control subjects; participants in class B were older and showed longer reaction times. Hence AM perceptual dysfunctions are not specific for schizophrenia, yet AM may be a promising stage marker.

Perception of a hectic hospital environment at admission relates to acute stress disorder symptoms in myocardial infarction patients.

OBJECTIVE Hospital crowding is a public health problem that may impact on the quality of medical treatment and increase the risk of developing traumatic stress, e.g., after myocardial infarction (MI). This study examines whether subjective appraisal of crowding at hospital admission due to MI is associated with acute stress disorder (ASD) symptoms. METHOD We investigated 102 consecutive patients with acute MI within 48h after having reached stable circulatory conditions. The appraisal of crowding was measured by the retrospective assessment of the perception of a hectic hospital environment at admission. Furthermore, patients completed the Acute Stress Disorder Scale to rate the psychological stress reaction. RESULTS The perception of a hectic hospital environment was associated with the development of ASD symptoms (r=0.254, P=.013) independently of demographic, peritraumatic and medical factors. Post hoc analysis revealed associations with dissociative (r=0.211, P=.041), reexperiencing (r=0.184, P=.074) and arousal (r=0.179, P=.083) symptoms. CONCLUSION The findings suggest that, besides objective circumstances, the way hospital admission due to MI is perceived by the patient may influence the development of MI-triggered ASD symptoms. The psychological and physiological long-term outcomes of the perception of a hectic hospital environment and the role of preventive interventions need further examination.

Perception of non-invasive ventilation in adult Swiss intensive care units

The real utilisation scenario of non-invasive ventilation (NIV) in Swiss ICUs has never been reported. Using a survey methodology, we developed a questionnaire sent to the directors of the 79 adult ICUs to identify the perceived pattern of NIV utilisation. We obtained a response rate of 62%. The overall utilisation rate for NIV was 26% of all mechanical ventilations, but we found significant differences in the utilisation rates among different linguistic areas, ranging from 20% in the German part to 48% in the French part (p <0.01). NIV was mainly indicated for the acute exacerbations of COPD (AeCOPD), acute cardiogenic pulmonary edema (ACPE) and acute respiratory failure (ARF) in selected do-not-intubate patients. In ACPE, CPAP was much less used than bi-level ventilation and was still applied in AeCOPD. The first line interface was a facial mask (81%) and the preferred type of ventilator was an ICU machine with an NIV module (69%). The perceived use of NIV is generally high in Switzerland, but regional variations are remarkable. The indications of NIV use are in accordance with international guidelines. A high percentage of units consider selected do-not-intubate conditions as an important additional indication.