Abnormalities in visual perception are not at the foreground of schizophrenia symptomatology [1Giersch A., Lalanne L., Isope P. Implicit Timing as the Missing Link between Neurobiological and Self-Disorders in Schizophrenia? Front Hum Neurosci 2016 ;  10 : 303

Cliccare qui per andare alla sezione Riferimenti, 2Martin B., Franck N., Cermolacce M., Falco A., Benair A., Etienne E., e al. Fragile temporal prediction in patients with schizophrenia is related to minimal self-disorders Sci Rep 2017 ;  7 : 8278

Cliccare qui per andare alla sezione Riferimenti, 3Silverstein S.M., Keane B.P. Perceptual organization impairment in schizophrenia and associated brain mechanisms: review of research from 2005 to 2010 Schizophr Bull 2011 ;  37 : 690-699 [cross-ref]

Cliccare qui per andare alla sezione Riferimenti]. They are nonetheless often found in the patients’ complaints during prodromal phases, and have been described as one of the best predictor of schizophrenia conversion. What is the link between perceptual disorders and clinical symptoms in schizophrenia ? After a short discussion of different perceptual abnormalities, we will focus on the time structure of perception, that illustrates possible links between low-level perception disorders, predictive coding and the sense of minimal self (the self that helps to feel as being present here and now).

We tested the link between the sense of self and time disorders in 28 stabilized patients with schizophrenia and 24 matched controls. We evaluated time expectation, as indexed by the ability to benefit from the passage of time to react to a visual target : expectation increases with time, leading to shorter reaction times. We additionally check to which amount this phenomena is modulated when the targets are missing in some trials, and can be compensated for by attention cues. In parallel, minimal self-disorders were evaluated with the EASE (phenomenological scale).

Patients can expect sensory signals and react to unusual events like missing targets as well as controls. However, the patients who display disorders of the minimal self (EASE) do not benefit from the passage of time, and all patients display disrupted time expectation when the occurrence of events is uncertain.

The results suggest a link between timing and minimal self disorders. Time expectation helps to link events with one another and to transform a chain of discontinuous events in a continuous flow. Conversely, fragile time expectations may lead to a sense of discontinuity, which could disrupt the flow of sensory signals, thus contributing to minimal self-disorders.