Background: Deficits in emotion perception are a well-established phenomenon in schizophrenic patients and studies have typically used unimodal emotion tasks, presenting either emotional faces or emotional vocalizations. We introduced bimodal emotion conditions in two previous studies in order to study the process of multisensory integration of visible and audible emotion cues. We now build on our earlier work and address the regulatory effects of selective attention mechanisms on the ability to integrate emotion cues stemming from multisensory channels.
Methods: We added a neutral secondary distractor condition to the original bimodal paradigm in order to investigate modality-specific selective attention mechanisms. We compared schizophrenic patients (n=50) to non-schizophrenic psychotic patients (n=46), as well as to healthy controls (n=50). A trained psychiatrist used the Schedules of Clinical Assessment in Neuropsychiatry (SCAN 2.1) to diagnose the patients.
Results: As expected, in healthy controls, and to a lesser extent in non-schizophrenic psychotic patients, modality-specific attention attenuated multisensory integration of emotional faces and vocalizations. Conversely, in schizophrenic patients, auditory and visual distractor conditions yielded unaffected and even exaggerated multisensory integration.
Conclusions: These results suggest that schizophrenics, as compared to healthy controls and non-schizophrenic psychotic patients, have modality-specific attention deficits when attempting to integrate information regarding emotions that stem from multichannel sources. Various explanations for our findings, as well as their possible consequences, are discussed.
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