Schizophrenia and autism are two severe neurodevelopmental disorders associating with a wide range of similar clinical manifestations such as impairments in social cognition and social interaction.  

Most recent findings also suggest that these two clinical groups may in fact be closely related to the same continuum of neurodevelopmental disorders. One of the hallmark features of both schizophrenia and autism share is the impairment observed in sensory and multisensory integration.   

Atypical sensory processing across different modalities (e.g., vision, hearing, touch and olfaction) is associated with emotional problems and impaired social functions that characterize these two neurodevelopmental disorders.  

In addition to unisensory processing, the integration of multisensory stimuli is particularly important for perception of complex social information. For example, social interactions require the integration of another person’s face, voice, lip movement and gestures, failure of which may lead to misinterpretation and abnormal social responses.  

Recent studies have suggested that both schizophrenia and autism demonstrate diminished multisensory integration, especially for linguistic and social contexts.  

Specifically for multisensory integration, close temporal proximity is a crucial cue to binding and integrating associated stimuli. When this temporal cue becomes less precise and we combine unrelated stimuli which should otherwise be separated, such a broadened "temporal binding window" (TBW) could result in an improperly filtered and unpredictable sensory environment.  

In fact, there is converging evidence that TBW is extended in both schizophrenia and autism. However, little is known about the differences and similarities of the mechanisms underlying the prolonged TBW in these two clinical groups, let alone its cascading effect on social and communicative deficits. 

Dr. Raymond Chan's team from the Neuropsychology and Applied Cognitive Neuroscience (NACN) Laboratory of the Chinese Academy of Sciences has carried out a meta-analysis to systematically and quantitatively review the literature on temporal integration impairment in autism and schizophrenia spectrum disorders.  

They have included 21 studies in systematic review and 14 studies in final meta-analysis (N=8 for schizophrenia and N=6 for autism). Their findings showed that sensory temporal integration impairment was robustly reported in both autism and schizophrenia spectrum disorders, and these impairments were comparable in these two clinical groups.  

Subgroup analysis of unisensory and multisensory (mainly bimodal audiovisual integration) further showed that heterogeneous and unstable effects for unisensory temporal binding were observed in individuals with autism spectrum disorders. However, there was a more consistent and severe impairment in multisensory temporal integration represented by an enlarged temporal binding window found in both autistic and schizophrenia spectrum disorders.  

Dr. Chan's meta-analysis suggests that consistent and robust impairment of higher-level multisensory temporal integration was exhibited in both autism and schizophrenia spectrum disorders.  

Multisensory dysfunction was further found to be associated with symptoms like hallucinations, impaired social communications and self-disturbance in these two clinical groups.  

Dr. Chan and his team suggest we should focus more work to understand the specific mechanisms of prolonged temporal binding windows observed in these two clinical groups.  

They also urge clinicians and researchers to develop specific intervention to improve multisensory temporal functions because these deficits seem less responsive to traditional medication.   

The paper is now available in Neuroscience & Biobehavioral Reviews entitled "Multisensory temporal binding window in autism spectrum disorders and schizophrenia spectrum disorders: A systematic review and meta-analysis".    

This study was supported by the Beijing Municipal Science & Technology Commission Grant, the National Key Research and Development Programme, the Beijing Training Project for the Leading Talents in Science & Technology, the CAS Key Laboratory of Mental Health, Institute of Psychology, and the CAS/SAFEA International Partnership Programme for Creative Research Teams.