Neurological soft signs in schizophrenia spectrum disorders are not confounded by current antipsychotic dosage

Neurological soft signs and thyroid hormones in schizophrenia spectrum disorders

BACKGROUND

Neurological soft signs (NSS) are minor sensory and motor deviations linked to neurodevelopmental disorders and schizophrenia spectrum disorders (SSD). Thyroid hormones (TH) are essential for neurodevelopment and are suggested to be altered in SSD. Yet, the relationship between NSS and TH is unclear.

OBJECTIVES

We evaluated the relationship between NSS and TH in individuals with SSD.

METHODS

We examined a total of 72 individuals with SSD. We assessed NSS using the Neurological Evaluation Scale (NES) and clinical symptoms using the Positive and Negative Syndrome Scale (PANSS). We collected fasting blood samples to measure serum levels of thyroid-stimulating hormone (TSH), free thyroxine (fT4), and free triiodothyronine (fT3). We used the t-test to compare differences between sex and the Pearson correlation to test for correlations between NSS, TH and psychopathology separately for males and females.

RESULTS

We observed a negative correlation between fT4 and NES total score (r = -0.374, p = .032), and NES subdomain "sensory integration" (r = -0.372, p = .033). The correlation between fT4 and "sensory integration" remained largely unchanged when controlling for age, DOI, and antipsychotic dose in OLZ equivalents by performing partial correlation analyses (r = -0.424, p = .049). Serum fT3 and TSH levels exhibited no significant correlation with NES scores but the PANSS negative symptoms score was negatively associated with fT3 (r = -0.472, p < .001).

CONCLUSIONS

Lower fT4 levels were associated with NSS severity and specific NSS subdomains only in male individuals. In the overall sample, we detected a significant negative correlation between fT3 and negative symptoms. Future studies should examine a larger sample of drug-naïve individuals with SSDs, followed-up longitudinally in time to infer causality.

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.

Structured neurological soft signs examination reveals motor coordination deficits in adults diagnosed with high-functioning autism

Neurological soft signs (NSS), discrete deficits in motor coordination and sensory integration, have shown promise as markers in autism diagnosis. While motor impairments, partly associated with core behavioral features, are frequently found in children with autism, there is limited evidence in adults. In this study, NSS were assessed in adults undergoing initial diagnosis of high-functioning autism (HFA), a subgroup difficult to diagnose due to social adaptation and psychiatric comorbidity. Adults with HFA (n = 34) and 1:1 sex-, age-, and intelligence-matched neurotypical controls were administered a structured NSS examination including motor, sensory, and visuospatial tasks. We showed that adults with HFA have significantly increased motor coordination deficits compared with controls. Using hierarchical cluster analysis within the HFA group, we also identified a subgroup that was particularly highly affected by NSS. This subgroup differed from the less affected by intelligence level, but not severity of autism behavioral features nor global psychological distress. It remains questionable whether motor impairment represents a genuinely autistic trait or is more a consequence of factors such as intelligence. Nevertheless, we conclude that examining NSS in terms of motor coordination may help diagnose adults with HFA and identify HFA individuals who might benefit from motor skills interventions.

Neurological soft signs and cognition among inpatients with schizophrenia

Introduction: Evidence has shown that neurological soft signs are strongly associated with neurocognitive dysfunction. Therefore, the primary objective of this study was to assess the association between NSS and cognitive impairments in a sample of inpatients with schizophrenia. The secondary objective was to explore the association between NSS total scores and functioning.Methods: The study enrolled 95 inpatients diagnosed with schizophrenia disorders and 45 healthy controls. The neurological evaluation scale (NES) was used to assess neurological soft sign while the Brief Assessment of Cognition in Schizophrenia (BACS) was used to evaluate cognitive functioning in patients with schizophrenia.Results: Patients with schizophrenia had significantly higher mean scores on the NES total test and subtests than the control group. Higher cognition was significantly associated with lower NES total and subtest scores. Higher functional independence was significantly associated with a lower NES total score (Beta = -.25), lower motor coordination subtest score (Beta = -.04), and lower others subtest (Beta = -.12). When taking the functional independence scale as the dependent variable, a higher NES total score was significantly associated with lower functioning (Beta = -0.03).Conclusion: NSS were associated to neurocognitive impairments in almost every domain among patients with schizophrenia. Further prospective research is still needed to confirm this role.

Neurological Soft Signs in Schizophrenia, a Picture of the Knowledge in the Last Decade: A Scoping Review

(1) Background: Neurological Soft Signs (NSS) are subtle neurological abnormalities that are more common in schizophrenia patients than in healthy individuals and have been regularly observed in neuroleptic-naive first-episode patients, supporting the hypothesis that they are an intrinsic component of schizophrenia. (2) Methods: a review of articles published in the last ten years (from January 2013 to January 2023) was carried out on articles published in ScienceDirect and PubMed, by following the PRISMA Statement extension for scoping reviews (PRISMA-ScR), which evaluated the impact of NSS in correlation with the symptomatology, neuroleptic treatment, and the cerebral structural changes of patients with schizophrenia. (3) Results: thirty articles were included, among them twelve included MRI structural evaluation and four studies with a longitudinal design. (4) Conclusions: interest in researching NSS has increased in recent years, but questions remain about their origin and relationship to schizophrenia symptoms, thus this study aims to fill in information gaps in the hope that future research will help provide individualized treatment. It is suggested that NSS in schizophrenia might have an inherited genetic relationship pattern, thus being in line with a trait viewpoint. Most of the research revealed that schizophrenia patients had higher NSS scores than healthy controls, however, they were rather similar to their first-degree relatives, thus, also arguing in favor of a trait perspective. The greatest improvement in scores is seen in those with a remitting course, as shown by declining NSS ratings concurrent with symptomatology.

The neural substrates of neurological soft signs in schizophrenia: a systematic review

Neurological soft signs (NSS) are common in patients with schizophrenia. However, the neural substrates of NSS remain poorly understood. Using legacy PubMed, we performed a systematic review and included studies that assessed NSS and obtained neuroimaging data in patients with a schizophrenia spectrum disorder published up to June 2020. We systematically reviewed 35 relevant articles. Studies consistently implicate the basal ganglia and cerebellum as structural substrates of NSS and suggest that somatomotor and somatosensory regions as well as areas involved in visual processing and spatial orientation may underlie NSS in psychosis spectrum disorders. Additionally, dysfunction of frontoparietal and cerebellar networks has been implicated in the pathophysiology of NSS. The current literature outlines several structural and functional brain signatures that are relevant for NSS in schizophrenia spectrum disorder. The majority of studies assessed gray matter structure, but only a few studies leveraged other imaging methods such as diffusion weighted imaging, or molecular imaging. Due to this, it remains unclear if white matter integrity deficits or neurometabolic alterations contribute to NSS in the illness. While a substantial portion of the literature has been conducted in patients in the early illness stages, mitigating confounds of illness chronicity, few studies have been conducted in antipsychotic medication-naïve patients, which is a clear limitation. Furthermore, only little is known about the temporal evolution of NSS and associated brain signatures. Future studies addressing these pivotal gaps in our mechanistic understanding of NSS will be important.

Using Virtual Reality as a Tool in the Rehabilitation of Movement Abnormalities in Schizophrenia

Movement abnormalities are prevalent across all stages of schizophrenia contributing to poor social functioning and reduced quality of life. To date, treatments are scarce, often involving pharmacological agents, but none have been shown to improve movement abnormalities effectively. Virtual reality (VR) is a tool used to simulate virtual environments where behavioral performance can be quantified safely across different tasks while exerting control over stimulus delivery, feedback and measurement in real time. Sensory information is transmitted via a head mounted display allowing users to directly interact with virtual objects and bodies using gestures and body movements in the real world to perform different actions, permitting a sense of immersion in the simulated virtual environment. Although, VR has been widely used for successful motor rehabilitation in a variety of different neurological domains, none have been exploited for motor rehabilitation in schizophrenia. The objectives of this article are to review movement abnormalities specific to schizophrenia, and how VR can be utilized to restore and improve motor functioning in patients with schizophrenia. Constructing VR-mediated motor-cognitive interventions that can help in retaining and transferring the learned outcomes to real life are also discussed.

Moving forward: distinct sensorimotor abnormalities predict clinical outcome after 6 months in patients with schizophrenia

Despite substantial efforts in the last decades, objective measures that can predict clinical outcome in patients with schizophrenia (SZ) after an acute psychotic episode are still lacking. Here, we introduced a comprehensive assessment of sensorimotor function to predict mid-term clinical outcome following an acute psychotic episode. This naturalistic follow-up of 43 patients with DSM-IV-TR diagnosis of SZ examined sensorimotor abnormalities (i.e. Neurological Soft Signs (NSS), parkinsonism, akathisia, catatonia and acute dyskinesia), psychopathology, cognition and psychosocial functioning using well-established instruments. A collection of statistical methods was used to examine the relationship between sensorimotor domain, psychopathology, cognition and psychosocial functioning. We also tested the clinical feasibility of this relationship when predicting clinical outcome after an acute psychotic episode. Longitudinal data were collected on 43 individuals after a follow-up period of >6 months. At follow-up, patients showed significantly reduced general symptom severity, as well as decreased levels of NSS, parkinsonism and catatonia. Further, NSS scores at baseline predicted PANSS negative scores and cognitive functioning at baseline. Finally, NSS scores at baseline predicted symptom change (reduction of PANSS positive and negative scores) at follow-up. In conclusion, our results suggest that NSS are significant predictors of poor clinical outcome in SZ at baseline and >6 months after an acute psychotic episode. These findings propose sensorimotor domain as state biomarker of SZ and support its predictive power with respect to treatment outcome.