title: Reduced susceptibility to the sound-induced flash fusion illusion in schizophrenia.
abstract: Schizophrenia is characterised by the presence of abnormal complex sensory perceptual experiences. Such experiences could arise as a consequence of dysfunctional multisensory integration. We used the sound-induced flash illusion paradigm, which probes audiovisual integration using elementary visual and auditory cues, in a sample of individuals with schizophrenia (n=40) and matched controls (n=22). Signal detection theory analyses were performed to characterise patients' and controls' sensitivity in distinguishing 1 and 2 flashes under varying auditory conditions. Both groups experienced significant fission illusions (whereby one visual flash, accompanied by two auditory beeps, is misperceived as two flashes) and fusion illusions (whereby two flashes, accompanied by one beep, are perceived as one flash). Patients showed significantly lower fusion illusion rates compared to HC, while the fission illusion occurred similarly frequently in both groups. However, using an SDT approach, we compared illusion conditions with unimodal visual conditions, and found that illusory visual perception was overall more strongly influenced by auditory input in HC compared to patients for both illusions. This suggests that multisensory integration may be impaired on a low perceptual level in SZ.
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, de Crespigny Park, London SE5 8AF, United Kingdom. Electronic address: lucy.vanes@kcl.ac.uk.
authors.forename: Lucy D
authors.initials: LD
authors.lastname: Vanes
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, de Crespigny Park, London SE5 8AF, United Kingdom; School of Psychology, University of Birmingham, Edgbaston, Birmingham B15 2TT, United Kingdom.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: White
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, de Crespigny Park, London SE5 8AF, United Kingdom.
authors.forename: Rebekah L
authors.initials: RL
authors.lastname: Wigton
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, de Crespigny Park, London SE5 8AF, United Kingdom.
authors.forename: Dan
authors.initials: D
authors.lastname: Joyce
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, de Crespigny Park, London SE5 8AF, United Kingdom.
authors.forename: Tracy
authors.initials: T
authors.lastname: Collier
authors.affiliation: Institute of Psychiatry, Psychology and Neuroscience, de Crespigny Park, London SE5 8AF, United Kingdom.
authors.forename: Sukhi S
authors.initials: SS
authors.lastname: Shergill
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001307:Auditory Perception; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009903:Optical Illusions; D010468:Perceptual Disorders / Q000175:diagnosis* / Q000523:psychology*; D010775:Photic Stimulation; D011618:Psychotic Disorders / Q000175:diagnosis* / Q000523:psychology*; D012559:Schizophrenia / Q000175:diagnosis*; D012565:Schizophrenic Psychology
keywords: Fission illusion; Fusion illusion; Multisensory integration; Schizophrenia