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Recent literature has suggested that deficits in sensory processing are associated with schizophrenia (SCZ), and more specifically hallucination severity. The DSM-5’s shift towards a dimensional approach to diagnostic criteria has led to SCZ and schizotypal personality disorder (SPD) being classified as schizophrenia spectrum disorders. With SCZ and SPD overlapping in aetiology and symptomatology, such as sensory abnormalities, it is important to investigate whether these deficits commonly reported in SCZ extend to non-clinical expressions of SPD. In this study, we investigated whether levels of SPD traits were related to audiovisual multisensory temporal processing in a non-clinical sample, revealing two novel findings. First, less precise multisensory temporal processing was related to higher overall levels of SPD symptomatology. Second, this relationship was specific to the cognitive–perceptual domain of SPD symptomatology, and more specifically, the Unusual Perceptual Experiences and Odd Beliefs or Magical Thinking symptomatology. The current study provides an initial look at the relationship between multisensory temporal processing and schizotypal traits. Additionally, it builds on the previous literature by suggesting that less precise multisensory temporal processing is not exclusive to SCZ but may also be related to non-clinical expressions of schizotypal traits in the general population.

Recent literature has suggested that atypical sensory processing observed in schizophrenia may contribute to clinical symptomatology. Specifically, multisensory temporal processing was shown to be strongly associated with hallucination severity. Here, we explored whether this relationship extends to a broader spectrum of schizotypal traits, in line with the DSM-5’s shift towards a more dimensional approach to diagnostic criteria within Schizophrenia Spectrum Disorders. Fifty-one participants completed an audiovisual temporal order judgment task as a measure of multisensory temporal processing and self-reported levels of schizotypal traits using the Schizotypal Personality Questionnaire. These data revealed two novel findings. First, less precise multisensory temporal processing was related to higher overall levels of schizotypal traits. Second, this relationship was specific to the cognitive-perceptual domain, and more specifically, the Unusual Perceptual Experiences and Odd Beliefs or Magical Thinking measures. Previous literature has shown that less precise multisensory temporal processing was related to the severity of hallucinations in schizophrenia. These findings provide a novel, direct extension of this previous work by demonstrating that this relationship applies to traits across the schizophrenia spectrum, including at the subclinical level.

Multisensory integration, the process by which sensory information from different sensory modalities are bound together, is hypothesized to contribute to perceptual symptomatology in schizophrenia, in whom multisensory integration differences have been consistently found. Evidence is emerging that these differences extend across the schizophrenia spectrum, including individuals in the general population with higher levels of schizotypal traits. In the current study, we used the McGurk task as a measure of multisensory integration. We measured schizotypal traits using the Schizotypal Personality Questionnaire (SPQ), hypothesizing that higher levels of schizotypal traits, specifically Unusual Perceptual Experiences and Odd Speech subscales, would be associated with decreased multisensory integration of speech. Surprisingly, Unusual Perceptual Experiences were not associated with multisensory integration. However, Odd Speech was associated with multisensory integration, and this association extended more broadly across the Disorganized factor of the SPQ, including Odd or Eccentric Behaviour. Individuals with higher levels of Odd or Eccentric Behaviour scores also demonstrated poorer lip-reading abilities, which partially explained performance in the McGurk task. This suggests that aberrant perceptual processes affecting individuals across the schizophrenia spectrum may relate to disorganized symptomatology.