Lost in time and space? Multisensory processing of peripersonal space and time perception in Depersonalisation

Abstract

Perception of one’s self and body in time and space are fundamental aspects of self-consciousness. It scaffolds our subjective experience of being present, in the here and now, a vital condition for our survival and wellbeing. Depersonalisation (DP) is characterized by distressing feeling of being ‘spaced out’, detached from one’s self, body and the world, as well as atypical ‘flat’ time perception. Using a multisensory audio-tactile paradigm, we have conducted a study looking at the effect of DP experiences on peripersonal space (PPS) (i.e. the space close to the body) and time perception. Based on previous findings reporting altered PPS perception in schizophrenia patients and high schizotypal individuals, we hypothesized that people with higher occurrences of DP experiences would show similarly an altered PPS representation. Strikingly, we found no difference in PPS perception in people with high versus low occurrences of DP experiences. This suggests that anomalous PPS perception in DP and schizophrenic traits individuals may be underlined by different mechanisms. To assess time perception in relation to DP, we have used the Mental Time Travel (MTT) task measuring the individuals’ capacity to take one’s present as reference point for situating personal versus general events in the past and in the future. We found that people with higher occurrences of DP showed an overall poorer performance in locating events in time relative to their present reference point. By contrast, people with low occurrences of DP showed significant variation in performance when answering to relative past events. Consistent with phenomenological self-reports of ‘flatness’ of one’s temporal flow, people with higher occurrences of DP did not display this variation. Our study sheds further light on the close link between altered sense of self and egocentric spatiotemporal perception in Depersonalization, the third most common psychological symptom in the general population (after anxiety and low mood).