Confirmatory Factor Analysis in Neurophysiological and Neuropsychological Dimensions of Schizophrenia

Free visual exploration of natural movies in schizophrenia

BACKGROUND

Eye tracking dysfunction (ETD) observed with standard pursuit stimuli represents a well-established biomarker for schizophrenia. How ETD may manifest during free visual exploration of real-life movies is unclear.

METHODS

Eye movements were recorded (EyeLink®1000) while 26 schizophrenia patients and 25 healthy age-matched controls freely explored nine uncut movies and nine pictures of real-life situations for 20 s each. Subsequently, participants were shown still shots of these scenes to decide whether they had explored them as movies or pictures. Participants were additionally assessed on standard eye-tracking tasks.

RESULTS

Patients made smaller saccades (movies (p = 0.003), pictures (p = 0.002)) and had a stronger central bias (movies and pictures (p < 0.001)) than controls. In movies, patients' exploration behavior was less driven by image-defined, bottom-up stimulus saliency than controls (p < 0.05). Proportions of pursuit tracking on movies differed between groups depending on the individual movie (group*movie p = 0.011, movie p < 0.001). Eye velocity on standard pursuit stimuli was reduced in patients (p = 0.029) but did not correlate with pursuit behavior on movies. Additionally, patients obtained lower rates of correctly identified still shots as movies or pictures (p = 0.046).

CONCLUSION

Our results suggest a restricted centrally focused visual exploration behavior in patients not only on pictures, but also on movies of real-life scenes. While ETD observed in the laboratory cannot be directly transferred to natural viewing conditions, these alterations support a model of impairments in motion information processing in patients resulting in a reduced ability to perceive moving objects and less saliency driven exploration behavior presumably contributing to alterations in the perception of the natural environment.

Exploring functioning in schizophrenia: Predictors of functional capacity and real-world behaviour

Impairment in daily functioning still represents a major treatment issue in schizophrenia and a more in-depth knowledge of underlying constructs is crucial for interventions to translate into better outcomes. This study aims to model factors influencing both functional capacity and real-life behaviour in a sample of outpatients with chronic schizophrenia, through a comprehensive assessment including evaluations of psychopathology, cognitive and social cognitive abilities, premorbid adjustment, family environment and early childhood experiences. No significant correlation was observed between functional capacity and real-life behaviour. Functional capacity was significantly predicted by IQ, while real-life behaviour was significantly predicted by empathy, affect recognition and symptoms. Functional capacity seems mainly related to neurocognition, whereas real-life behaviour appears more complex, requiring the integration of different factors including symptoms, with a major role of empathy. Results thus support a divergence between the two constructs of functioning and their underlying components and highlight the need to target both dimensions through individualized sequential rehabilitation programs in order to optimize functional outcome.