Multisensory processes can compensate for attention deficits in schizophrenia

Studies on schizophrenia (SCZ) and aberrant multisensory integration (MSI) show conflicting results. These divergent results are potentially confounded by attention deficits in SCZ. To test this, we examined the interplay between MSI and intersensory attention (IA) in healthy controls (N=27) and in SCZ (N=27). Evoked brain potentials to unisensory-visual (V), unisensory-tactile (T) or bisensory VT stimuli were measured with high density electroencephalography, whilst participants attended block-wise to either visual or tactile inputs. Behaviourally, IA effects in SCZ are uncompromised for bisensory stimuli, but diminished for unisensory stimuli. At the neural level, we observed reduced IA effects for bisensory stimuli over mediofrontal scalp regions (230-320ms) in SCZ. The analysis of MSI revealed multiple phases of integration over occipital and frontal scalp regions (240-364ms), with comparable performance between HC and SCZ. The magnitudes of IA and MSI effects were both positively related to the behavioural performance in SCZ, indicating that IA and MSI mutually facilitate bisensory stimulus processing. Our study suggests that widely intact MSI, which facilitates stimulus processing, can compensate for top-down attention deficits in SCZ. Further, the interplay of IA and MSI implies that differences in attentional demands may account for previous conflicting findings on MSI in schizophrenia.