Passage of time at the level of milliseconds : a new approach and a selective difficulty in individuals with schizophrenia

Abstract Background and Hypothesis Individuals with schizophrenia report that to them time sometimes feels discontinuous. Previous work has shown a link between the sense of self, and the ability to prepare to react to a target and to benefit from the passage of time, at the level of a few hundreds of milliseconds. However, the sense of time continuity requires a higher time resolution than examined in previous studies. Here we investigate to which extent individuals with schizophrenia and controls benefit from an increased delay when detecting asynchronies in the order of tens of milliseconds (stimulus onset asynchronies, i.e. SOA) between two successive visual stimuli. Study Design We re-analyzed three datasets and contrasted performance when the SOA increases, remains identical or decreases from trial t-1 to trial t. Study Results Performance of all participants improved with an increase in the SOA, as the task became easier, but for controls more so than individuals with schizophrenia. These results are replicated across datasets, and were specific to the condition when SOA increased from one trial to the next. There was no significant group difference when the SOA decreased or remained identical. This was true even when the latter condition was more frequent, and when SOA magnitude was equalized across the conditions. Importantly, the difference between the two groups was specific to temporal judgements, and was not observed in a control masking task. Conclusions We suggest the results reveal a difficulty for individuals with schizophrenia to experience time at the level of milliseconds.