Dysbalanced Resting-State Functional Connectivity Within the Praxis Network Is Linked to Gesture Deficits in Schizophrenia

Neural substrates for dissociation of cognition inhibition in autogenous- and reactive-type obsessive-compulsive disorder

BACKGROUND

The taxonomy of autogenous- and reactive-type obsessive-compulsive disorder (OCD) (AO vs. RO) is one of the most valid subtyping approaches to the heterogeneity of OCD. The present study aimed to seek evidence of neural substrates supporting the dissociation of cognition inhibition in AO and RO which was revealed by our previous behavioral and electrophysiological work.

METHODS

A total of 165 patients with OCD (86 AO versus 79 RO), and 79 healthy controls (HC) underwent resting-state functional magnetic resonance imaging scans. Within-network connectivity, node strength, and edge-wise functional connectivity (FC) in cognition and response inhibition networks were calculated. Results from 3 cognition and 2 response inhibition network atlases were compared to confirm the robustness of the findings.

RESULTS

Both AO and RO showed lower within-network connectivity in response inhibition networks, while lower within cognition inhibition network connectivity was only detected in AO. Besides shared weaker node strength in the anterior insula (AI), anterior cingulate cortex (ACC), and supplementary motor area (SMA), AO had a broader range of nodes within cognition inhibition networks exhibiting weaker strength, including nodes in right inferior frontal gyrus (IFG), left parietal and occipital regions. Decreased FC of left AI-CC, left IFG-ACC, and frontal-parietal regions in cognition inhibition networks were found in AO.

CONCLUSIONS

Findings indicate that unlike deficits in connectivity within response inhibition networks which may reflect a common pathology in AO and RO, deficits in connectivity within cognition inhibition networks were more pronounced in AO. These findings strengthen our insight into the heterogeneity in OCD.

Gesticulation in individuals with at risk mental states for psychosis

Nonverbal communication (NVC) is a complex behavior that involves different modalities that are impaired in the schizophrenia spectrum, including gesticulation. However, there are few studies that evaluate it in individuals with at-risk mental states (ARMS) for psychosis, mostly in developed countries. Given our prior findings of reduced movement during speech seen in Brazilian individuals with ARMS, we now aim to determine if this can be accounted for by reduced gesticulation behavior. Fifty-six medication-naïve ARMS and 64 healthy controls were filmed during speech tasks. The frequency of specifically coded gestures across four categories (and self-stimulatory behaviors) were compared between groups and tested for correlations with prodromal symptoms of the Structured Interview for Prodromal Syndromes (SIPS) and with the variables previously published. ARMS individuals showed a reduction in one gesture category, but it did not survive Bonferroni's correction. Gesture frequency was negatively correlated with prodromal symptoms and positively correlated with the variables of the amount of movement previously analyzed. The lack of significant differences between ARMS and control contradicts literature findings in other cultural context, in which a reduction is usually seen in at-risk individuals. However, gesture frequency might be a visual proxy of prodromal symptoms, and of other movement abnormalities. Results show the importance of analyzing NVC in ARMS and of considering different cultural and sociodemographic contexts in the search for markers of these states.

Self-reported Gesture Interpretation and Performance Deficits in Individuals at Clinical High Risk for Psychosis

BACKGROUND AND HYPOTHESIS

Deficits in performing and interpreting communicative nonverbal behaviors, such as gesture, have been linked to varied psychopathology and dysfunction. Some evidence suggests that individuals at risk for psychosis have deficits in gesture interpretation and performance; however, individuals with internalizing disorders (eg, depression) may have similar deficits. No previous studies have examined whether gesture deficits in performance and interpretation are specific to those at risk for psychosis. Additionally, the underlying mechanisms (eg, cognition) and consequences (eg, functioning) of these deficits are poorly understood.

STUDY DESIGN

This study examined self-reported gesture interpretation (SRGI) and performance (SRGP) in those at clinical high risk for psychosis (CHR; N = 88), those with internalizing disorders (INT; N = 51), and healthy controls (HC; N = 53). Participants completed questionnaires, clinical interviews, and neurocognitive tasks.

STUDY RESULTS

Results indicated that the CHR group was characterized by significantly lower SRGI scores than the HC or INT groups (d = 0.41); there were no differences among groups in SRGP. Within CHR participants, greater deficits in SRGP were associated with lower verbal learning and memory (r = -.33), but not general intelligence or processing speed. Furthermore, gesture deficits were associated with higher cross-sectional risk for conversion to a full psychotic disorder in the CHR group.

CONCLUSIONS

Overall, these findings suggest that specific subdomains of gesture may reflect unique vulnerability for psychosis, self-report may be a viable assessment tool in understanding these phenomena, and gesture dysfunction may signal risk for transition to psychosis.

Using dynamic point light display stimuli to assess gesture deficits in schizophrenia

Background

Gesture deficits are ubiquitous in schizophrenia patients contributing to poor social communication and functional outcome. Given the dynamic nature of social communications, the current study aimed to explore the underlying socio-cognitive processes associated with point-light-displays (PLDs) of communicative gestures in the absence of any other confounding visual characteristics, and compare them to other well-established stimuli of gestures such as pictures by examining their association with symptom severity and motor-cognitive modalities.

Methods

We included 39-stable schizophrenia outpatients and 27-age-gender matched controls and assessed gesture processing using two tasks. The first task used static stimuli of pictures of a person performing a gesture. The limbs executing the gesture were missing and participants' task was to choose the correct gesture from three-options provided. The second task included videos of dynamic PLDs interacting with each other. One PLD performed communicative gestures, while the other PLD imitated/followed these performed gestures. Participants had to indicate, which of the two PLDs was imitating/following the other. Additionally, we evaluated symptom severity, as well as, motor and cognitive parameters.

Results

Patients underperformed in both gesture tasks compared to controls. Task performance for static stimuli was associated with blunted affect, motor coordination and sequencing domains, while PLD performance was associated with expressive gestures and sensory integration processes.

Discussion

Gesture representations of static and dynamic stimuli are associated with distinct processes contributing to poor social communication in schizophrenia, requiring novel therapeutic interventions. Such stimuli can easily be applied remotely for screening socio-cognitive deficits in schizophrenia.

Motor abnormalities are associated with poor social and functional outcomes in schizophrenia

BACKGROUND

Up to 50% of patients with schizophrenia are suffering from motor abnormalities, which may contribute to decreased quality of life, impaired work capacity, and a reduced life expectancy by 10-20 years. However, the effect of motor abnormalities on social and global functioning, as well as, functional capacity is not clear. We hypothesized, that the presence of motor abnormalities is associated with poorer functional outcomes in patients with schizophrenia.

METHODS

We collected data on 5 different motor abnormalities in 156 patients suffering from schizophrenia spectrum disorders: parkinsonism, catatonia, dyskinesia, neurological soft signs and psychomotor slowing (PS). Additionally, we used three different scales to evaluate the functional outcomes in these patients: the Global Assessment of Functioning (GAF) and the Social and Occupational Functioning Assessment Scale (SOFAS) which use clinicians' judgment; and one using a performance-based measure of functional capacity, the brief version of the UCSD Performance-based Skills Assessment (UPSA-B).

RESULTS

Our analysis demonstrated that patients with catatonia (all F > 4.5; p < 0.035) and parkinsonism (all F > 4.9; p < 0.027) scored lower on GAF and SOFAS compared to patients without catatonia and parkinsonism. In contrast, no significant difference on functional outcomes between patients with dyskinesia versus without dyskinesia exist in our study. Furthermore, there are statistically significant negative correlations for parkinsonism and PS with GAF, SOFAS and UPSA-B (all tau are at least -0.152, p-value <0.036). We also found significant negative correlations between catatonia and both GAF & SOFAS (all tau are at least -0.203, p-value<0.001) and between NES and SOFAS (tau = -0.137, p-value = 0.033).

CONCLUSION

Here, we showed that four of the most common motor abnormalities observed in schizophrenia were associated with at least one of the patients' functional outcomes. The stronger the motor impairment was the worse the global and social functioning. Future studies need to test, whether amelioration of motor abnormalities is linked to improved community functioning.

Altered temporal variability in brain functional connectivity identified by fuzzy entropy underlines schizophrenia deficits

Investigation of the temporal variability of resting-state brain networks informs our understanding of how neural connectivity aggregates and disassociates over time, further shedding light on the aberrant neural interactions that underlie symptomatology and psychosis development. In the current work, an electroencephalogram-based sliding window analysis was utilized for the first time to measure the nonlinear complexity of dynamic resting-state brain networks of schizophrenia (SZ) patients by applying fuzzy entropy. The results of this study demonstrated the attenuated temporal variability among multiple electrodes that were distributed in the frontal and right parietal lobes for SZ patients when compared with healthy controls (HCs). Meanwhile, a concomitant strengthening of the posterior and peripheral flexible connections that may be attributed to the excessive alertness or sensitivity of SZ patients to the external environment was also revealed. These temporal fluctuation distortions combined reflect an abnormality in the coordination of functional network switching in SZ, which is further the source of worse task performance (i.e., P300 amplitude) and the negative relationship between individual complexity metrics and P300 amplitude. Notably, when using the network metrics as features, multiple linear regressions of P300 amplitudes were also exactly achieved for both the SZ and HC groups. These findings shed light on the pathophysiological mechanisms of SZ from a temporal variability perspective and provide potential biomarkers for quantifying SZ's progressive neurophysiological deterioration.

Limbic links to paranoia: increased resting-state functional connectivity between amygdala, hippocampus and orbitofrontal cortex in schizophrenia patients with paranoia

Paranoia is a frequent and highly distressing experience in psychosis. Models of paranoia suggest limbic circuit pathology. Here, we tested whether resting-state functional connectivity (rs-fc) in the limbic circuit was altered in schizophrenia patients with current paranoia. We collected MRI scans in 165 subjects including 89 patients with schizophrenia spectrum disorders (schizophrenia, schizoaffective disorder, brief psychotic disorder, schizophreniform disorder) and 76 healthy controls. Paranoia was assessed using a Positive And Negative Syndrome Scale composite score. We tested rs-fc between bilateral nucleus accumbens, hippocampus, amygdala and orbitofrontal cortex between groups and as a function of paranoia severity. Patients with paranoia had increased connectivity between hippocampus and amygdala compared to patients without paranoia. Likewise, paranoia severity was linked to increased connectivity between hippocampus and amygdala. Furthermore, paranoia was associated with increased connectivity between orbitofrontal and medial prefrontal cortex. In addition, patients with paranoia had increased functional connectivity within the frontal hubs of the default mode network compared to healthy controls. These results demonstrate that current paranoia is linked to aberrant connectivity within the core limbic circuit and prefrontal cortex reflecting amplified threat processing and impaired emotion regulation. Future studies will need to explore the association between limbic hyperactivity, paranoid ideation and perceived stress.

Brain Stimulation and Group Therapy to Improve Gesture and Social Skills in Schizophrenia-The Study Protocol of a Randomized, Sham-Controlled, Three-Arm, Double-Blind Trial

An important component of nonverbal communication is gesture performance, which is strongly impaired in 2/3 of patients with schizophrenia. Gesture deficits in schizophrenia are linked to poor social functioning and reduced quality of life. Therefore, interventions that can help alleviate these deficits in schizophrenia are crucial. Here, we describe an ongoing randomized, double-blind 3-arm, sham-controlled trial that combines two interventions to reduce gesture deficits in schizophrenia patients. The combined interventions are continuous theta burst stimulation (cTBS) and social cognitive remediation therapy (SCRT). We will randomize 72 patients with schizophrenia spectrum disorders in three different groups of 24 patients. The first group will receive real cTBS and real SCRT, the second group will receive sham cTBS and real SCRT, and finally the third group will receive sham SCRT. Here, the sham treatments are, as per definition, inactive interventions that mimic as closely as possible the real treatments (similar to placebo). In addition, 24 age- and gender-matched controls with no interventions will be added for comparison. Measures of nonverbal communication, social cognition, and multimodal brain imaging will be applied at baseline and after intervention. The main research aim of this project will be to test whether the combination of cTBS and SCRT improves gesture performance and social functioning in schizophrenia patients more than standalone cTBS, SCRT or sham psychotherapy. We hypothesize that the patient group receiving the combined interventions will be superior in improving gesture performance.

CLINICAL TRIAL REGISTRATION

[www.ClinicalTrials.gov], identifier [NCT04106427].

Hand gesture performance is impaired in major depressive disorder: A matter of working memory performance?

OBJECTIVE

Individuals with depression exhibit numerous interpersonal deficits. As effective use of gestures is critical for social communication, it is possible that depressed individuals' interpersonal deficits may be due to deficits in gesture performance. The present study thus compared gesture performance of depressed patients and controls and examined whether these deficits relate to cognitive and other domains of dysfunction.

METHODS

Gesture performance was evaluated in 30 depressed patients and 30 controls using the Test of Upper Limb Apraxia (TULIA). Clinical rating scales were assessed to determine if gesture deficits were associated with motor, cognitive or functional outcomes.

RESULTS

Compared to controls, depressed patients exhibited impaired gesture performance with 2/3 of the patients demonstrating gesture deficits. Within depressed patients, gesture performance was highly correlated with working memory abilities. In contrast, no association between gesture performance and gestural knowledge, psychomotor retardation, depression severity, or frontal dysfunction was observed in patients.

LIMITATIONS

This is a cross-sectional study and a larger size would have allowed for confident detection of more subtle, but potentially relevant effects.

CONCLUSION

Gesture performance is impaired in depressed patients, and appears to be related to poor working memory abilities, suggesting a disruption in the retrieval of gestural cues indicative of a distinct clinical phenomenon that might be related to social functioning.

Neural Basis of Speech-Gesture Mismatch Detection in Schizophrenia Spectrum Disorders

Patients with schizophrenia spectrum disorders (SSD) exhibit an aberrant perception and comprehension of abstract speech-gesture combinations associated with dysfunctional activation of the left inferior frontal gyrus (IFG). Recently, a significant deficit of speech-gesture mismatch detection was identified in SSD, but the underlying neural mechanisms have not yet been examined. A novel mismatch-detection fMRI paradigm was implemented manipulating speech-gesture abstractness (abstract/concrete) and relatedness (related/unrelated). During fMRI data acquisition, 42 SSD patients (schizophrenia, schizoaffective disorder, or other non-organic psychotic disorder [ICD-10: F20, F25, F28; DSM-IV: 295.X]) and 36 healthy controls were presented with short video clips of an actor reciting abstract or concrete sentences accompanied by either a semantically related or unrelated gesture. Participants indicated via button press whether they perceived each gesture as matching the speech content or not. Speech-gesture mismatch detection performance was significantly impaired in patients compared to controls. fMRI data analysis revealed that patients showed lower activation in bilateral frontal areas, including the IFG for all abstract > concrete speech-gesture pairs. In addition, they exhibited reduced engagement of the right supplementary motor area (SMA) and bilateral anterior cingulate cortices (ACC) for unrelated > related stimuli. We provide first evidence that impaired speech-gesture mismatch detection in SSD could be the result of dysfunctional activation of the SMA and ACC. Failure to activate the left IFG disrupts the integration of abstract speech-gesture combinations in particular. Future investigations should focus on brain stimulation of the SMA, ACC, and the IFG to improve communication and social functioning in SSD.

Neural Correlates of Self-other Distinction in Patients with Schizophrenia Spectrum Disorders: The Roles of Agency and Hand Identity

Schizophrenia spectrum disorders (SSD) are characterized by disturbed self-other distinction. While previous studies associate abnormalities in the sense of agency (ie, the feeling that an action and the resulting sensory consequences are produced by oneself) with disturbed processing in the angular gyrus, passive movement conditions to isolate contributions of motor predictions are lacking. Furthermore, the role of body identity (ie, visual features determining whether a seen body part belongs to oneself) in self-other distinction is unclear. In the current study, fMRI was used to assess the roles of agency and hand identity in self-other distinction. Patients with SSD and healthy controls (HC) performed active and passive hand movements (agency manipulation) while seeing their own or someone else's hand moving in accordance with their action (hand identity manipulation). Variable delays (0-417 ms) between movement and feedback had to be detected. Our results showed overall lower delay detection performances during active than passive conditions; however, these differences were reduced in patients when the own hand was displayed. On a neural level, we found that in HC, activation in the right angular gyrus was modulated by agency and hand identity. In contrast, agency and hand identity revealed no overlapping activation in patients, due to reduced effects of agency. Importantly, HC and SSD patients shared similar effects of hand identity in the angular gyrus. Our results suggest that disturbances of self-other distinction in SSD are particularly driven by agency, while self-other distinction based on hand identity might be spared.

Gesture deficits and apraxia in schizophrenia

Aberrant performance of skilled action has long been noted in schizophrenia and relatedly, recent reports have demonstrated impaired use, performance, and perception of hand gestures in this group. Still, this deficit is not acknowledged as apraxia, which to the broader medical field, characterizes impairments in skilled actions. Understanding the relationship between apraxia and schizophrenia may shed an invaluable new perspective on disease mechanism, and highlight novel treatment opportunities as well. To examine this potential link, we reviewed the evidence for the types of praxis errors, associated psychopathology, and cerebral correlates of the praxis deficit in schizophrenia. Notably, the review indicated that gesture deficits are severe enough to be considered genuine apraxia in a substantial proportion of patients (about 25%). Further, other potential contributors (e.g., hypokinetic motor abnormalities, cognitive impairment) are indeed associated with gesture deficits in schizophrenia, but do not sufficiently explain the abnormality. Finally, patients with praxis deficits have altered brain structure and function including the left parieto-premotor praxis network and these neural correlates are specific to the praxis deficit. Therefore, we argue that the gestural disorder frequently observed in schizophrenia shares both the clinical and neurophysiological features of true apraxia, as in other neuropsychiatric disorders with impaired higher order motor control, such as Parkinson's disease.

Parietal lobe and disorganisation syndrome in schizophrenia and psychotic bipolar disorder: A bimodal connectivity study

Given the emerging evidence in support of parietal brain stimulation to treat speech disorder in psychosis, we investigated structural and functional parietal dysconnectivity in schizophrenia (n = 34) and bipolar disorder with psychotic symptoms (n = 16). We found that both patient groups demonstrated reduced left parietal structural connectivity compared to healthy controls (n = 32). The three groups also differed significantly on the variability of left and right parietal dynamic functional connectivity. In patients with schizophrenia, parietal dysconnectivity predicted the severity of disorganisation symptoms. These findings suggest that dysconnectivity between the parietal lobe and the rest of the brain plays a key role in disorganisation symptoms of schizophrenia.

Nonverbal communication remains untouched: No beneficial effect of symptomatic improvement on poor gesture performance in schizophrenia

BACKGROUND

Gestures are an important part of communication. Patients with schizophrenia present gesture deficits that tend to deteriorate in the course of the disease and hamper functional outcome. This gesture deficit has been associated with motor abnormalities, cognitive impairment, and psychotic symptoms. Unaffected, first-degree relatives of schizophrenia patients share some subclinical motor and cognitive abnormalities. We aimed to investigate, whether gesture performance changes with symptomatic improvement in patients, and to test the longitudinal performance in unaffected, first-degree relatives.

METHODS

In this study, we measured gesture performance using a validated test in 33 patients, 29 first-degree relatives and 38 healthy controls. Measurements were completed shortly after admission and before discharge in patients. Performance was rated blindly by experts using video recordings of the gesture task. Additionally, we evaluated cognitive function and psychotic symptoms at both visits.

RESULTS

Gesture performance was poorer in relatives compared to controls and poorer in patients compared to both relatives and controls. Patients showed an improvement in psychopathology but a significant decrease in gesture performance at follow-up, while performance in the other groups remained stable. Proportional change of gesture performance correlated with change of cognitive function in patients, whereas there were no correlations with change of cognitive function in the other groups.

CONCLUSION

While symptom severity was reduced, the gesture deficit further deteriorated in schizophrenia. The finding argues for distinct processes contributing to poor nonverbal communication skills in patients, requiring novel alternative treatment efforts.