Characterizing the sensorimotor domain in schizophrenia spectrum disorders

Deciphering white matter microstructural alterations in catatonia according to ICD-11: replication and machine learning analysis

Catatonia is a severe psychomotor disorder characterized by motor, affective and cognitive-behavioral abnormalities. Although previous magnetic resonance imaging (MRI) studies suggested white matter (WM) dysconnectivity in the pathogenesis of catatonia, it is unclear whether microstructural alterations of WM tracts connecting psychomotor regions might contribute to a better classification of catatonia patients. Here, diffusion-weighted MRI data were collected from two independent cohorts (whiteCAT/replication cohort) of patients with (n = 45/n = 13) and without (n = 56/n = 26) catatonia according to ICD-11 criteria. Catatonia severity was examined using the Northoff (NCRS) and Bush-Francis (BFCRS) Catatonia Rating Scales. We used tract-based spatial statistics (TBSS), tractometry (TractSeg) and machine-learning (ML) to classify catatonia patients from tractometry values as well as tractomics features generated by the newly developed tool RadTract. Catatonia patients showed fractional anisotropy (FA) alterations measured via TractSeg in different corpus callosum segments (CC_1, CC_3, CC_4, CC_5 and CC_6) compared to non-catatonia patients across both cohorts. Our classification results indicated a higher level of performance when trained on tractomics as opposed to traditional tractometry values. Moreover, in the CC_6, we successfully trained two classifiers using the tractomics features identified in the whiteCAT data. These classifiers were applied separately to the whiteCAT and replication cohorts, demonstrating comparable performance with Area Under the Receiver Operating Characteristics (AUROC) values of 0.79 for the whiteCAT cohort and 0.76 for the replication cohort. In contrast, training on FA tractometry resulted in lower AUROC values of 0.66 for the whiteCAT cohort and 0.51 for the replication cohort. In conclusion, these findings underscore the significance of CC WM microstructural alterations in the pathophysiology of catatonia. The successful use of an ML based classification model to identify catatonia patients has the potential to improve diagnostic precision.

Parkinsonism, Psychomotor Slowing, Negative and Depressive Symptoms in Schizophrenia Spectrum and Mood Disorders: Exploring Their Intricate Nexus Using a Network Analytic Approach

BACKGROUND AND HYPOTHESIS

Parkinsonism, psychomotor slowing, negative and depressive symptoms show evident phenomenological similarities across different mental disorders. However, the extent to which they interact with each other is currently unclear. Here, we hypothesized that parkinsonism is an independent motor abnormality showing limited associations with psychomotor slowing, negative and depressive symptoms in schizophrenia spectrum (SSD), and mood disorders (MOD).

STUDY DESIGN

We applied network analysis and community detection methods to examine the interplay and centrality (expected influence [EI] and strength) between parkinsonism, psychomotor slowing, negative and depressive symptoms in 245 SSD and 99 MOD patients. Parkinsonism was assessed with the Simpson-Angus Scale (SAS). We used the Positive and Negative Syndrome Scale (PANSS) to examine psychomotor slowing (item #G7), negative symptoms (PANSS-N), and depressive symptoms (item #G6).

STUDY RESULTS

In SSD and MOD, PANSS item #G7 and PANSS-N showed the largest EI and strength as measures of centrality. Parkinsonism had small or no influence on psychomotor slowing, negative and depressive symptoms in SSD and MOD. In SSD and MOD, exploratory graph analysis identified one community, but parkinsonism showed a small influence on its occurrence. Network Comparison Test yielded no significant differences between the SSD and MOD networks (global strength p value: .396 and omnibus tests p value: .574).

CONCLUSIONS

The relationships between the individual domains followed a similar pattern in both SSD and MOD highlighting their transdiagnostic relevance. Despite evident phenomenological similarities, our results suggested that parkinsonism is more independent of negative and depressive symptoms than psychomotor slowing in both SSD and MOD.

The Cerebellar Neuropsychiatric Rating Scale: A New Card in the Deck

Research on the cerebellum has come a long and impressive way. While traditionally assumed as only engaged in motor control, rediscovery of early literature reports and recent studies also point to the cerebellum´s role in vestibular and cognitive affective functioning at the frontiers of psychiatry. Indeed, damage to the cerebellum often leads to consequences in cognitive affective functioning, including deficits in executive, visuo-spatial and linguistic functioning as well as affect regulation. However, in order to further disseminate these scientific advances and to provide palpable progress to clinicians, smart tools that can be applied in daily clinical practice need to be developed. In particular, rating scales, which remain the most robust clinical method in the assessment of cerebellar patients, need to be developed. Although neuropsychiatric symptoms of cerebellar disease are common, they do not conform to DSM-5 diagnostic categories of psychiatric disorders. The Cerebellar Neuropsychiatric Rating Scale (CNRS), an informant-based questionnaire reported by Daly et al., may fill this gap, allowing clinicians for the first time to capture and quantify neuropsychiatric symptoms that have often been overlooked in ataxias in the past. The CNRS may represent a reliable instrument in ataxias. The scale offers a promising tool for early detection and targeted intervention, fostering interdisciplinary collaboration between neurologists, psychiatrists, and psychologists. Future developments may refine its clinical applicability, expand its use to other neurological disorders, and integrate digital health solutions to enhance real-world assessment and treatment.

Manual dexterity and grip force are distinctly linked to domains of neurological soft signs in schizophrenia spectrum disorders

Motor abnormalities are highly prevalent among patients with schizophrenia spectrum disorders. Very likely, motor control processes, such as dexterity and grip force (GF), are impaired in schizophrenia. We aimed to explore associations between various motor abnormalities and motor control processes and to investigate whether specific motor abnormalities predict the performance of fine motor movements and GF. Our analyses included 198 patients with schizophrenia spectrum disorders. We applied well-established standardized motor rating scales to assess five different motor abnormalities: psychomotor slowing (PS), neurological soft signs (NSS), parkinsonism, catatonia, and dyskinesia. As a measure of manual dexterity, we used the coin rotation (CR) task, requiring patients to rotate a coin between their thumb, index, and middle finger. Maximal grip strength was measured with the GF task. Correlation analyses revealed that both CR and GF performances were associated with different motor abnormalities, most strongly with NSS (CR: tau = -0.263, p < 0.001; GF: tau = -0.208, p < 0.001). Hierarchical regression showed that NSS predicted performance on the CR and GF task better compared to PS, parkinsonism, and catatonia alone (CR: ∆R2 = 0.09, F = 22.26, p < 0.001; GF: ∆R2 = 0.02, F = 6.61, p < 0.001). When looking within the NSS domains, CR performance was predicted better by motor coordination and sequencing of motor acts, whereas GF was predicted better by sensory integration. Motor control processes are influenced by different motor abnormalities, especially NSS. Our results suggest that distinct aspects of NSS affect fine motor movements and GF. This knowledge is important for designing specific novel interventions aimed at improving specific motor control processes.

Sensori- and psychomotor abnormalities, psychopathological symptoms and functionality in schizophrenia-spectrum disorders: a network analytic approach

Sensori- and psychomotor abnormalities are an inherent part of schizophrenia-spectrum disorders (SSD) pathophysiology and linked to psychopathological symptoms as well as cognitive and global functioning. However, how these different symptom clusters simultaneously interact with each other is still unclear. Here, we examined 192 SSD patients (37.75 ± 12.15 years, 73 females). First, we investigated the cross-sectional prevalence and overlap of individual sensori- and psychomotor abnormalities. Second, we applied network analysis methods to simultaneously model the associations between Neurological Soft Signs (NSS), level of akathisia, parkinsonism symptoms, tardive dyskinesia (TD) and catatonia signs as well as cognition, psychopathology, global functioning and daily antipsychotic dose. The largest centralities were exhibited by NSS (0.90), catatonia signs (0.82) and global functioning (0.79). NSS showed strong partial correlations with cognition and parkinsonism symptoms (edge weight, ew = 0.409 and ew = 0.318, respectively). Catatonia signs showed strong connections with global functioning (ew = 0.333). In contrast, TD, akathisia and daily antipsychotic dose were weakly connected with other variables (e.g., largest ew=0.176 between TD and akathisia). In conclusion, NSS and cognition, parkinsonism symptoms and NSS as well as catatonia signs and global functioning seem to be preferentially connected in SSD. The daily medication had little influence on sensori- and psychomotor abnormalities, indicating that they are features of core SSD pathophysiology. Future studies should incorporate these relationships to enhance the understanding of SSD.

Multidimensional outcome of first-episode psychosis: a network analysis

BACKGROUND

Few studies have examined the long-term outcomes of first-episode psychosis (FEP) among patients beyond symptomatic and functional remission. This study aimed to broaden the scope of outcome indicators by examining the relationships between 12 outcomes of FEP patients at 20.9 years after their initial diagnosis.

METHODS

At follow-up, 220 out of 550 original patients underwent a new assessment. Twelve outcomes were assessed via semistructured interviews and complementary scales: symptom severity, functional impairment, personal recovery, social disadvantage, physical health, number of suicide attempts, number of episodes, current drug use, dose-years of antipsychotics (DYAps), cognitive impairment, motor abnormalities, and DSM-5 final diagnosis. The relationships between these outcome measures were investigated using Spearman's correlation analysis and exploratory factor analysis, while the specific connections between outcomes were ascertained using network analysis.

RESULTS

The outcomes were significantly correlated; specifically, symptom severity, functioning, and personal recovery showed the strongest correlations. Exploratory factor analysis of the 12 outcomes revealed two factors, with 11 of the 12 outcomes loading on the first factor. Network analysis revealed that symptom severity, functioning, social disadvantage, diagnosis, cognitive impairment, DYAps, and number of episodes were the most interconnected outcomes.

CONCLUSION

Network analysis provided new insights into the heterogeneity between outcomes among patients with FEP. By considering outcomes beyond symptom severity, the rich net of interconnections elucidated herein can facilitate the development of interventions that target potentially modifiable outcomes and generalize their impact on the most interconnected outcomes.

3D-optical motion capturing examination of sensori- and psychomotor abnormalities in mental disorders: Progress and perspectives

Sensori-/psychomotor abnormalities refer to a wide range of disturbances in individual motor, affective and behavioral functions that are often observed in mental disorders. However, many of these studies have mainly used clinical rating scales, which can be potentially confounded by observer bias and are not able to detect subtle sensori-/psychomotor abnormalities. Yet, an innovative three-dimensional (3D) optical motion capturing technology (MoCap) can provide more objective and quantifiable data about movements and posture in psychiatric patients. To draw attention to recent rapid progress in the field, we performed a systematic review using PubMed, Medline, Embase, and Web of Science until May 01st 2024. We included 55 studies in the qualitative analysis and gait was the most examined movement. The identified studies suggested that sensori-/psychomotor abnormalities in neurodevelopmental, mood, schizophrenia spectrum and neurocognitive disorders are associated with alterations in spatiotemporal parameters (speed, step width, length and height; stance time, swing time, double limb support time, phases duration, adjusting sway, acceleration, etc.) during various movements such as walking, running, upper body, hand and head movements. Some studies highlighted the advantages of 3D optical MoCap systems over traditional rating scales and measurements such as actigraphy and ultrasound gait analyses. 3D optical MoCap systems are susceptible to detecting differences not only between patients with mental disorders and healthy persons but also among at-risk individuals exhibiting subtle sensori-/psychomotor abnormalities. Overall, 3D optical MoCap systems hold promise for objectively examining sensori-/psychomotor abnormalities, making them valuable tools for use in future clinical trials.

Deciphering the interplay between psychopathological symptoms, sensorimotor, cognitive and global functioning: a transdiagnostic network analysis

BACKGROUND

Understanding the relationship between psychopathology and major domains of human neurobehavioral functioning may identify new transdiagnostic treatment targets. However, studies examining the interrelationship between psychopathological symptoms, sensorimotor, cognitive, and global functioning in a transdiagnostic sample are lacking. We hypothesized a close relationship between sensorimotor and cognitive functioning in a transdiagnostic patient sample.

METHODS

We applied network analysis and community detection methods to examine the interplay and centrality [expected influence (EI) and strength] between psychopathological symptoms, sensorimotor, cognitive, and global functioning in a transdiagnostic sample consisting of 174 schizophrenia spectrum (SSD) and 38 mood disorder (MOD) patients. All patients (n = 212) were examined with the Positive and Negative Syndrome Scale (PANSS), the Heidelberg Neurological Soft Signs Scale (NSS), the Global Assessment of Functioning (GAF), and the Brief Cognitive Assessment Tool for Schizophrenia consisted of trail making test B (TMT-B), category fluency (CF) and digit symbol substitution test (DSST).

RESULTS

NSS showed closer connections with TMT-B, CF, and DSST than with GAF and PANSS. DSST, PANSS general, and NSS motor coordination scores showed the highest EI. Sensory integration, DSST, and CF showed the highest strength.

CONCLUSIONS

The close connection between sensorimotor and cognitive impairment as well as the high centrality of sensorimotor symptoms suggests that both domains share aspects of SSD and MOD pathophysiology. But, because the majority of the study population was diagnosed with SSD, the question as to whether sensorimotor symptoms are really a transdiagnostic therapeutic target needs to be examined in future studies including more balanced diagnostic groups.

Catatonia

Catatonia is a neuropsychiatric disorder characterized by motor, affective and cognitive-behavioural signs, which lasts from hours to days. Intensive research over the past two decades has led to catatonia being recognized as an independent diagnosis in the International Classification of Diseases, 11th Revision (ICD-11) since 2022. Catatonia is found in 5-18% of inpatients on psychiatric units and 3.3% of inpatients on medical units. However, in an unknown number of patients, catatonia remains unrecognized and these patients are at risk of life-threatening complications. Hence, recognizing the symptoms of catatonia early is crucial to initiate appropriate treatment to achieve a favourable outcome. Benzodiazepines such as lorazepam and diazepam, electroconvulsive therapy, and N-methyl-D-aspartate antagonists such as amantadine and memantine, are the cornerstones of catatonia therapy. In addition, dopamine-modulating second-generation antipsychotics (for example, clozapine and aripiprazole) are effective in some patient populations. Early and appropriate treatment combined with new screening assessments has the potential to reduce the high morbidity and mortality associated with catatonia in psychiatric and non-psychiatric settings.

The association between alterations in motor and cognitive dimensions of schizophrenia-spectrum disorders: A systematic review

Motor and cognitive alterations in schizophrenia-spectrum disorders (SSD) share common neural underpinnings, highlighting the necessity for a thorough exploration of the connections between these areas. This relationship is crucial, as it holds potential significance in unraveling the underlying mechanisms of SSD pathophysiology, ultimately leading to advancements in clinical staging and treatment strategies. The purpose of this review was to characterize the relationship between different hyper and hypokinetic domains of motor alterations and cognition in SSD. We systematically searched the literature (PROSPERO protocol CRD42019145964) and selected 66 original scientific contributions for review, published between 1987 and 2022. A narrative synthesis of the results was conducted. Hyper and hypokinetic motor alterations showed weak to moderate negative correlations with cognitive function across different SSD stages, including before antipsychotic treatment. The literature to date shows a diverse set of methodologies and composite cognitive scores hampering a strong conclusion about which specific cognitive domains were more linked to each group of motor alterations. However, executive functions seemed the domain more consistently associated with parkinsonism with the results regarding dyskinesia being less clear. Akathisia and catatonia were scarcely discussed in the reviewed literature. The present review reinforces the intimate relationship between specific motor alterations and cognition. Identified gaps in the literature challenge the formulation of definitive conclusions. Nevertheless, a discussion of putative underlying mechanisms is included, prompting guidance for future research endeavors.

Clinical and Sociodemographic Correlations with Neurological Soft Signs in Hospitalized Patients with Schizophrenia: A Preliminary Longitudinal Study

Schizophrenia is a severe, chronic neuropsychiatric disorder characterized by symptoms that profoundly impact behavior, cognition, perception, and emotions, leading to a reduced quality of life and physical impairment. Given the complexity of schizophrenia, there is a pressing need for clinical markers and tools to predict its course, enhance disease staging, facilitate early intervention, improve differential diagnosis, and tailor individualized treatment approaches. Previous studies focused on the relationship between neurological soft signs (NSS) and factors such as age, illness duration, and symptomatology, indicating NSS as state markers improving in parallel with psychotic symptom remission or predicting treatment resistance. However, there is a lack of consensus on NSS assessment tools, hindering routine clinical monitoring despite diagnostic and prognostic potential. The present longitudinal study involved 81 psychiatric inpatients diagnosed with schizophrenia. Patients were assessed at three time points: baseline, 1 month, and 6 months. The examination included the use of scales to evaluate psychotic and neurological symptoms, as well as the identification of adverse extrapyramidal reactions caused by neuroleptic treatment. The progression of NSS was correlated to both the symptomatology and the sociodemographic data of the patients. The main findings from the present investigation revealed a statistical correlation between NSS and psychopathological symptoms, especially with negative symptoms of schizophrenia. However, it is important to note that neuroleptic side effects only had a limited impact on NSS. Therefore, instead of being linked to extrapyramidal symptoms caused by neuroleptics, NSS appears to be more frequently related with symptoms of schizophrenia. Our findings provide further support for their strong association with the course of schizophrenia, independent of treatment side effects, thus emphasizing their potential as reliable assessment tools in both research and clinical settings.

Microstructural white matter biomarkers of symptom severity and therapy outcome in catatonia: Rationale, study design and preliminary clinical data of the whiteCAT study

The number of magnetic resonance imaging (MRI) studies on neuronal correlates of catatonia has dramatically increased in the last 10 years, but conclusive findings on white matter (WM) tracts alterations underlying catatonic symptoms are still lacking. Therefore, we conduct an interdisciplinary longitudinal MRI study (whiteCAT) with two main objectives: First, we aim to enroll 100 psychiatric patients with and 50 psychiatric patients without catatonia according to ICD-11 who will undergo a deep phenotyping approach with an extensive battery of demographic, psychopathological, psychometric, neuropsychological, instrumental and diffusion MRI assessments at baseline and 12 weeks follow-up. So far, 28 catatonia patients and 40 patients with schizophrenia or other primary psychotic disorders or mood disorders without catatonia have been studied cross-sectionally. 49 out of 68 patients have completed longitudinal assessment, so far. Second, we seek to develop and implement a new method for semi-automatic fiber tract delineation using active learning. By training supportive machine learning algorithms on the fly that are custom tailored to the respective analysis pipeline used to obtain the tractogram as well as the WM tract of interest, we plan to streamline and speed up this tedious and error-prone task while at the same time increasing reproducibility and robustness of the extraction process. The goal is to develop robust neuroimaging biomarkers of symptom severity and therapy outcome based on WM tracts underlying catatonia. If our MRI study is successful, it will be the largest longitudinal study to date that has investigated WM tracts in catatonia patients.

Extension, translation and preliminary validation of the Northoff Scale for Subjective Experience in Catatonia (NSSC)

BACKGROUND

In the last two decades, much neuroscientific research has been done on the pathomechanisms of catatonia. However, catatonic symptoms have mainly been assessed with clinical rating scales based on observer ratings. Although catatonia is often associated with strong affective reactions, the subjective domain of catatonia has simply been neglected in scientific research.

METHODS

The main objective of this study was to modify, extend and translate the original German version of the Northoff Scale for Subjective Experience in Catatonia (NSSC) and to examine its preliminary validity and reliability. Data were collected from 28 patients diagnosed with catatonia associated with another mental disorder (6A40) according to ICD-11. Descriptive statistics, correlation coefficients, internal consistency and principal component analysis were employed to address preliminary validity and reliability of the NSSC.

RESULTS

NSSC showed high internal consistency (Cronbach's alpha = 0.92). NSSC total scores were significantly associated with Northoff Catatonia Rating Scale (r = 0.50, p < .01) and Bush Francis Catatonia Rating Scale (r = 0.41, p < .05) thus supporting its concurrent validity. There was no significant association between NSSC total score and Positive and Negative Symptoms Scale total (r = 0.26, p = .09), Brief Psychiatric Rating Scale (r = 0.29, p = .07) and GAF (r = 0.03, p = .43) scores.

CONCLUSION

The extended version of the NSSC consists of 26 items and was developed to assess the subjective experience of catatonia patients. Preliminary validation of the NSSC revealed good psychometric properties. NSSC is a useful tool for everyday clinical work to assess the subjective experience of catatonia patients.

Psychomotor slowing in schizophrenia is associated with cortical thinning of primary motor cortex: A three cohort structural magnetic resonance imaging study

Psychomotor slowing (PS) is characterized by slowed movements and lower activity levels. PS is frequently observed in schizophrenia (SZ) and distressing because it impairs performance of everyday tasks and social activities. Studying brain topography contributing to PS in SZ can help to understand the underlying neurobiological mechanisms as well as help to develop more effective treatments that specifically target affected brain areas. Here, we conducted structural magnetic resonance imaging (sMRI) of three independent cohorts of right-handed SZ patients (SZ#1: n = 72, SZ#2: n = 37, SZ#3: n = 25) and age, gender and education matched healthy controls (HC) (HC#1: n = 40, HC#2: n = 37, HC#3: n = 38). PS severity in the three SZ cohorts was determined using the Positive and Negative Syndrome Scale (PANSS) item #G7 (motor retardation) and Trail-Making-Test B (TMT-B). FreeSurfer v7.2 was used for automated parcellation and segmentation of cortical and subcortical regions. SZ#1 patients showed reduced cortical thickness in right precentral gyrus (M1; p = 0.04; Benjamini-Hochberg [BH] corr.). In SZ#1, cortical thinning in right M1 was associated with PANSS item #G7 (p = 0.04; BH corr.) and TMT-B performance (p = 0.002; BH corr.). In SZ#1, we found a significant correlation between PANSS item #G7 and TMT-B (p = 0.005, ρ=0.326). In conclusion, PANSS G#7 and TMT-B might have a surrogate value for predicting PS in SZ. Cortical thinning of M1 rather than alterations of subcortical structures may point towards cortical pathomechanism underlying PS in SZ.

Structure/function interrelationships and illness insight in patients with schizophrenia: a multimodal MRI data fusion study

Illness insight in schizophrenia (SZ) has an important impact on treatment outcome, integration into society and can vary over the course of the disorder. To deal with and treat reduced or absent illness insight, we need to better understand its functional and structural correlates. Previous studies showed regionally abnormal brain volume in brain areas related to cognitive control and self-reference. However, little is known about associations between illness insight and structural and functional network strength in patients with SZ. This study employed a cross-sectional design to examine structural and functional differences between patients with SZ (n = 74) and healthy controls (n = 47) using structural and resting-state functional magnetic resonance imaging (MRI). Voxel-based morphometry was performed on structural data, and the amplitude of low frequency fluctuations (ALFF) was calculated for functional data. To investigate abnormal structure/function interrelationships and their association with illness insight, we used parallel independent component analysis (pICA). Significant group (SZ vs. HC) differences were detected in distinct structural and functional networks, predominantly comprising frontoparietal, temporal and cerebellar regions. Significant associations were found between illness insight and two distinct structural networks comprising frontoparietal (pre- and postcentral gyrus, inferior parietal lobule, thalamus, and precuneus) and posterior cortical regions (cuneus, precuneus, lingual, posterior cingulate, and middle occipital gyrus). Finally, we found a significant relationship between illness insight and functional network comprising temporal regions (superior temporal gyrus). This study suggests that aberrant structural and functional integrity of neural systems subserving cognitive control, memory and self-reference are tightly coupled to illness insight in SZ.

Catatonia-like behavior and immune activation: a crosstalk between psychopathology and pathology in schizophrenia

BACKGROUND

In Kalhbaum's first characterization of catatonia, the emotional symptoms, such as decreased or restricted expression of feelings and emotions, which is described as blunted affect, are related to the motor symptoms. In later years, the affective domain was excluded from the concept of catatonia and was not included among the diagnostic criteria in the various Diagnostic Statistical Manual (DSM) versions. In recent times, some authors have proposed the proposition of reevaluating the notion of catatonia through the reintroduction of the affective domain. The objective of this study was to examine the correlation between catatonic-like behavior (CLB), such as emotional withdrawal, blunted affect, and psychomotor slowing, and inflammatory markers, namely the neutrophil/lymphocytes ratio (NLR) and lymphocytes/monocytes ratio (LMR), in individuals diagnosed with schizophrenia.

METHOD

A sample of 25 patients with schizophrenia (10 females, 15 males) was recruited, and the Brief Psychiatric Rating Scale (BPRS) was used to assess the severity of emotional withdrawal, blunted affect, and psychomotor slowing.

FINDINGS

The correlation analysis (Spearman ρ) revealed a robust direct association between blunted affect and psychomotor slowing (ρ = 0.79, P = 0.001), and a significant direct correlation between CLB (emotional withdrawal, ρ = 0.51, P = 0.05; blunted affect ρ = 0.58, P = 0.05; motor retardation, ρ = 0.56, P = 0.05) and LMR (ρ = 0.53, P = 0.05). In addition, patients with a duration of illness (DOI) older than five years had a higher presence of CLB and a higher LMR than patients with a more recent diagnosis of the disease. Likely, patients with positive symptoms and in the prodromal and active stages of the disease have a different immune profile than patients in the residual stage and with a predominance of negative symptoms.

CONCLUSIONS

Psychomotor slowing and blunted affect are two significantly related features, representing the two-faced Janus of immobility. Furthermore, aggregating them in CLB is more predominant the longer the duration of schizophrenia and is associated with different a specific pattern of immune activation.

Dysconnection and cognition in schizophrenia: A spectral dynamic causal modeling study

Schizophrenia (SZ) is a severe mental disorder characterized by failure of functional integration (aka dysconnection) across the brain. Recent functional connectivity (FC) studies have adopted functional parcellations to define subnetworks of large-scale networks, and to characterize the (dys)connection between them, in normal and clinical populations. While FC examines statistical dependencies between observations, model-based effective connectivity (EC) can disclose the causal influences that underwrite the observed dependencies. In this study, we investigated resting state EC within seven large-scale networks, in 66 SZ and 74 healthy subjects from a public dataset. The results showed that a remarkable 33% of the effective connections (among subnetworks) of the cognitive control network had been pathologically modulated in SZ. Further dysconnection was identified within the visual, default mode and sensorimotor networks of SZ subjects, with 24%, 20%, and 11% aberrant couplings. Overall, the proportion of discriminative connections was remarkably larger in EC (24%) than FC (1%) analysis. Subsequently, to study the neural correlates of impaired cognition in SZ, we conducted a canonical correlation analysis between the EC parameters and the cognitive scores of the patients. As such, the self-inhibitions of supplementary motor area and paracentral lobule (in the sensorimotor network) and the excitatory connection from parahippocampal gyrus to inferior temporal gyrus (in the cognitive control network) were significantly correlated with the social cognition, reasoning/problem solving and working memory capabilities of the patients. Future research can investigate the potential of whole-brain EC as a biomarker for diagnosis of brain disorders and for neuroimaging-based cognitive assessment.

Correlates of neurological soft signs in bipolar disorder

Recent research has focused on neurological soft signs (NSS) in bipolar disorder (BD), but there is still scarce evidence on their correlates with other relevant variables. The aim of this study was to explore the association between NSS and clinical demographic, neurocognitive, and functional variables. Eighty-eight euthymic BD patients were included in whom NSS were assessed using the Neurological Evaluation Scale. All subjects performed an extensive neurocognitive battery selected to assess premorbid IQ, attention, language, verbal memory, and executive functions. Psychosocial outcomes were assessed by means of the Functioning Assessment Short Test. Among the demographical variables, NSS tended to be negatively associated with years of education and increased with age. Likewise, NSS were higher in BD type I than in BD type II, but independent of age at illness onset and number of previous affective episodes. There was a negative correlation between NSS and premorbid IQ, as well as with performance in attention, language, and executive functions. Results tended to be unchanged when controlled for potential confounders. Although NSS were associated with poor psychosocial functioning in the bivariate analysis, when added to a multiple regression model including neurocognition, these neurological features did not significantly contribute to the variance of the functional outcome. Our findings contribute to a better characterization of NSS in BD; their potential clinical and theoretical implications are discussed in the manuscript.