The Processing of Semantic Complexity and Cospeech Gestures in Schizophrenia: A Naturalistic, Multimodal fMRI Study

Language Network Dysfunction and Formal Thought Disorder in Schizophrenia

BACKGROUND

Pathophysiological inquiries into schizophrenia require a consideration of one of its most defining features: disorganization and impoverishment in verbal behavior. This feature, often captured using the term Formal Thought Disorder (FTD), still remains to be one of the most poorly understood and understudied dimensions of schizophrenia. In particular, the large-scale network level dysfunction that contributes to FTD remains obscure to date.

STUDY DESIGN

In this narrative review, we consider the various challenges that need to be addressed for us to move towards mapping FTD (construct) to a brain network level account (circuit).

STUDY RESULTS

The construct-to-circuit mapping goal is now becoming more plausible than it ever was, given the parallel advent of brain stimulation and the tools providing objective readouts of human speech. Notwithstanding this, several challenges remain to be overcome before we can decisively map the neural basis of FTD. We highlight the need for phenotype refinement, robust experimental designs, informed analytical choices, and present plausible targets in and beyond the Language Network for brain stimulation studies in FTD.

CONCLUSIONS

Developing a therapeutically beneficial pathophysiological model of FTD is a challenging endeavor, but holds the promise of improving interpersonal communication and reducing social disability in schizophrenia. Addressing the issues raised in this review will be a decisive step in this direction.

Gesture-speech synchrony in schizophrenia: A pilot study using a kinematic-acoustic analysis

Severe impairment of social functioning is the core feature of schizophrenia that persists despite treatment, and contributes to chronic functional disability. Abnormal non-verbal behaviors have been reported during interpersonal interactions but the temporal coordination of co-speech gestures with language abilities have been poorly studied to date in this pathology. Using the dynamical systems framework, the goal of the current study was to investigate whether gestures and speech synchrony is impaired in schizophrenia, exploring a new approach to report communicational skill disorders. Performing the first continuous kinematic-acoustic analysis in individuals with schizophrenia, we examined gesture-speech synchrony in solo spontaneous speech and in sensorimotor synchronization task. The experimental group consisted of twenty-eight participants with a diagnosis of schizophrenia and the control group consisted of twenty-four healthy participants age-gender-education matched. The results showed that spontaneous gesture-speech synchrony was preserved while intentional finger tapping-speech synchrony was impaired. In sensorimotor synchronization task, the schizophrenia group displayed greater asynchronies between finger tapping and syllable uttering and lower stability of coordination patterns. These findings suggest a specific deficit in time delay of information circulation and processing, especially in explicit functions. Thus, investigating intrapersonal coordination in schizophrenia may constitute a promising window into brain/behavior dynamic relationship.