Longitudinal study of neurological soft signs in first-episode early-onset psychosis

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.

Neurological and cerebellar soft signs in bipolar disorder: The role of staging, type and history of psychotic symptoms

AIM

Bipolar disorder (BD) patients show neurological abnormalities in form of neurological and cerebellar soft signs (NSS and CSS). NSS represents heterogeneous group of symptoms representing i.a. deficits of motor coordination, sequencing of complex motor acts and sensory integration. CSS were introduced as group of the neurological deficits of posture, gait, kinetic functions, eye movements and speech, associated more specifically to cerebellar abnormalities than NSS. Studies show significant effect size variability of those symptoms in BD group suggesting the existence of differing subpopulations. The aim of our study was to evaluate the effect of BD type, stage and the history of psychotic symptoms (HoPS) on the severity of CSS and NSS as none of the previous studies had verified the role of those categories.

METHODS

This study involved 181 participants: 116 euthymic BD patients (66 BD I, 50 BD II) and 65 healthy controls (HC). CSS was assessed with the International Cooperative Ataxia Rating Scale and NSS with Neurological Evaluation Scale. Patients were divided into early and late stage of the disorder according to Kapczinski's criteria. Rater was blind to patients' stage, type and HoPS.

RESULTS

Staging was related to vast majority of CSS and NSS scores. HoPS was related to oculomotor deficits. The effect of BD type was the least significant. Late stage BD showed more severe CSS and NSS than HC in every measure. There were no differences between early stage BD and HC, apart of posture and gait disturbances. Except of sensory integration scores, late stage BD showed higher CSS and NSS rates than early stage patients.

CONCLUSION

In this hitherto the largest study of neurological abnormalities in BD we have shown significant role of staging in CSS and NSS severity. Progression criteria based on inter-episode psychosocial functioning may stand as unrecognised factor responsible for variability observed in previous studies evaluating neurological abnormalities in BD. Our study suggests that in clinical practice NSS and CSS may be potentially used as easy-to-assess biological marker of BD staging. Observed severity of neurological impairments of BD patients may more likely correspond to the disease progression than to BD type and HoPS.

Neurological soft signs are associated with reduced medial-lateral postural control in adolescent athletes

INTRODUCTION

Neurological soft signs (NSS) are minor deviations from the norm in motor performance that are commonly assessed using neurological examinations. NSS may be of clinical relevance for evaluating the developmental status of adolescents. Here we investigate whether quantitative force plate measures may add relevant information to observer-based neurological examinations.

METHODS

Male adolescent athletes (n = 141) aged 13-16 years from three European sites underwent a neurological examination including 28 tests grouped into six functional clusters. The performance of tests and functional clusters was rated as optimal/non-optimal resulting in NSS+/NSS- groups and a continuous total NSS score. Participants performed a postural control task on a Balance Tracking System measured as path length, root mean square and sway area. ANCOVAs were applied to test for group differences in postural control between the NSS+ and NSS- group, and between optimal/non-optimal performance on a cluster- and test-level. Moreover, we tested for correlations between the total NSS score and postural control variables.

RESULTS

There was no significant overall difference between the NSS+ and NSS- group in postural control. However, non-optimal performing participants in the diadochokinesis test swayed significantly more in the medial-lateral direction than optimal performing participants. Moreover, a lower total NSS score was associated with reduced postural control in the medial-lateral direction.

CONCLUSION

Our findings demonstrate that NSS are related to postural control in adolescent athletes. Thus, force plate measures may add a quantitative, objective measurement of postural control to observer-based qualitative assessments, and thus, may complement clinical testing.

Neurological soft signs in adolescents are associated with brain structure

Neurological soft signs (NSS) are minor deviations in motor performance. During childhood and adolescence, NSS are examined for functional motor phenotyping to describe development, to screen for comorbidities, and to identify developmental vulnerabilities. Here, we investigate underlying brain structure alterations in association with NSS in physically trained adolescents. Male adolescent athletes (n = 136, 13–16 years) underwent a standardized neurological examination including 28 tests grouped into 6 functional clusters. Non-optimal performance in at least 1 cluster was rated as NSS (NSS+ group). Participants underwent T1- and diffusion-weighted magnetic resonance imaging. Cortical volume, thickness, and local gyrification were calculated using Freesurfer. Measures of white matter microstructure (Free-water (FW), FW-corrected fractional anisotropy (FAt), axial and radial diffusivity (ADt, RDt)) were calculated using tract-based spatial statistics. General linear models with age and handedness as covariates were applied to assess differences between NSS+ and NSS− group. We found higher gyrification in a large cluster spanning the left superior frontal and parietal areas, and widespread lower FAt and higher RDt compared with the NSS− group. This study shows that NSS in adolescents are associated with brain structure alterations. Underlying mechanisms may include alterations in synaptic pruning and axon myelination, which are hallmark processes of brain maturation.

Paternal age and specific neurological soft signs as reliable and valid neurobiological markers for the diagnosis of patients with schizophrenia

Advanced parental age at delivery and neurological soft signs (NSS) constitute risk factors for schizophrenia. The aim of the current study was to develop a neurobiological diagnostic index by combining them, and without the contribution of clinical symptomatology. The study sample included 133 patients suffering from schizophrenia according to DSM-IV-TR (77 males and 56 females; aged 33.55 ± 11.22 years old) and 122 normal controls (66 males and 56 females; aged 32.89 ± 9.91 years old). The assessment included the Neurological Evaluation Scale (NES), and a number of scales assessing the clinical symptoms and adverse effects. The statistical analysis included exploratory t-test, Pearson Correlation coefficient (R) and Discriminant Function Analysis (DFA). Exploratory t-tests and Pearson's R suggested that sex, parental age and NSS constitute independent components. On the basis of DFA results, the Psychotic Neurological Index was developed. At the cut-off PNI score of 8.5, sensitivity was equal to 94.74 and specificity to 93.44. The current is probably the first study to report on an easily obtainable diagnostic neurobiological marker with identifiable properties which is absolutely independent from the clinical manifestations and could serve in distinguishing between patients with schizophrenia and healthy controls with high efficacy.

Motor impairments in early onset schizophrenia

AIM

Motor impairments are frequent both at and before diagnosis. In childhood, impairments in general fine and gross motor function are among others identified using test batteries, and while elements of coordination are assessed in onset schizophrenia, the assessment of general motor functions is absent. Thus, we aimed to assess general motor function including childhood motor function in adolescents with schizophrenia in comparison with healthy controls and examine clinical correlates to general motor function.

METHOD

General fine and gross motor function was assessed using two standardized age-normed test batteries and a questionnaire in 25 adolescents with schizophrenia compared with age and gender-matched controls using t-test and χ² -test. Stepwise linear regression assessed potential developmental predictors on motor function including complications during childbirth, reported childhood motor function, executive function including false discovery rate q-values. Associations with schizophrenia symptom severity, executive function, cognitive function were assessed using Pearson's correlation and the impact of antipsychotic medication using t-test.

RESULT

All measures of motor function but one significantly differentiated adolescents with schizophrenia from healthy controls. The presence of schizophrenia (β =4.41, β = 10.96), explained the main part of the variance however, childhood motor function (β = .08) also added significantly to motor function. Executive function (β = -.45) was important for childhood motor function. Severity of schizophrenia was associated with strength (p < .0011) and manual coordination (p = .0295), and receiving antipsychotics affected manual dexterity (p = .0378).

CONCLUSION

The documentation of significant differences in general motor function in early onset schizophrenia compared with healthy controls highlights the need for general motor assessments and potential interventions.

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.

A systematic review of the prognostic value of motor abnormalities on clinical outcome in psychosis

Schizophrenia spectrum disorders have heterogeneous outcomes and currently no marker predicts the course of illness. Motor abnormalities (MAs) are inherent to psychosis, the risk of psychosis, symptom severity, and brain alterations. However, the prognostic value of MAs is still unresolved. Here, we provide a systematic review of longitudinal studies on the prognostic role of MAs spanning individuals at clinical high risk for psychosis (CHR), patients with first-episode psychosis (FEP), and chronic schizophrenia. We included 68 studies for a total of 23,630 subjects that assessed neurological soft signs (NSS), hypo- or hyperkinetic movement disorders and/or catatonia as a prognostic factor on clinical and functional outcomes. We found increased levels of MAs, in particular NSS, parkinsonism, and dyskinesia, were related to deteriorating symptomatic and poor functional outcome over time. Collectively, the findings emphasize the clinical, prognostic and scientific relevance of MA assessment and detection in individuals with or at risk of psychosis. In the future, instrumental measures of MA are expected to further augment detection, early intervention and treatment strategies in psychosis.

Neurological soft signs for discrimination between euthymic patients with bipolar I disorder and healthy controls

Background

Neurological soft signs in remitted state of bipolar disorder may represent trait deficits and the aim of this study was to examine the extent of neurological soft signs in euthymic patients with bipolar I disorder as compared to healthy controls. We conducted this study in Zagazig University Hospital upon 60 subjects divided into two groups: euthymic patients with bipolar I disorder group (30 patients) and control group (30 healthy individuals). Assessment of neurological soft signs was performed through Neurological Evaluation Scale and the euthymic state was determined by Young Mania Rating Scale and Hamilton Depression Rating Scale.

Results

The euthymic patient group exhibited a significantly worse performance in the total Neurological Evaluation Scale and the whole four subtest scores than healthy control subjects. There was a statistically significant association between total neurological soft sign score and mood stabilizer therapy in the studied patients. The age of onset of the disorder was correlated to the total score of Neurological Evaluation Scale which is statistically significant. The best cutoff points of the total neurological soft signs score in the discrimination between the euthymic patient group and control group was 3.5 according to the receiver operating characteristic curve.

Conclusion

This study may emphasize the role of neurological soft signs as a sign of organic brain disorder; however, further studies may be able to extend our findings to explore the etiology and pathogenesis of bipolar I disorder.

Neurological Signs at the First Psychotic Episode as Correlates of Long-Term Outcome: Results From the AESOP-10 Study

Minor neurological signs are subtle deficits in sensory integration, motor coordination, and sequencing of complex motor acts present in excess in the early stages of psychosis. Still, it remains unclear whether at least some of these signs represent trait or state markers for psychosis and whether they are markers of long-term disease outcome of clinical utility. We examined the relationship between neurological function at illness onset assessed with the Neurological Evaluation Scale and subsequent illness course in 233 patients from AESOP-10 (Aetiology and Ethnicity in Schizophrenia and Other Psychoses), a 10-year follow-up study of a population-based cohort of individuals recruited at the time of their first episode of psychosis in the United Kingdom. In 56 of these patients, we also explored changes in neurological function over time. We included a group of 172 individuals without psychosis as controls. After 10 years, 147 (63%) patients had developed a non-remitting course of illness, and 86 (37%) a remitting course. Already at first presentation, patients who developed a non-remitting course had significantly more primary, motor coordination, and total signs than both remitting patients and healthy controls. While Motor Coordination signs did not change over time, rates of Primary, Sensory Integration, and Total signs increased, independently of illness course type. These findings suggest that motor coordination problems could be a useful early, quick, and easily detectable marker of subsequent clinical outcome. With other motor abnormalities, a measure of motor incoordination could contribute to the identification of the most vulnerable individuals, who could benefit from targeted and more assertive treatment approaches.

Neurological soft signs and neurocognitive deficits in remitted patients with schizophrenia, their first-degree unaffected relatives, and healthy controls

Neurological soft signs (NSS) and neurocognitive deficits (ND) are highly prevalent in schizophrenia, and have been separately proposed as candidate endophenotypes of schizophrenia. However, few relevant studies focus on remitted patients with schizophrenia (RP) and integrate NSS and ND as a composite endophenotype. This study aimed to explore the NSS and ND and examine the comparative relationship between them in RP, their first-degree unaffected relatives (FDR), and healthy controls, furthermore, to seek potential endophenotypes subitems of NSS and ND and create a composite endophenotype. 86 RP, 86 FDR, and 86 healthy controls were included. NSS and ND were independently assessed with Cambridge Neurological Inventory and MATRICS^TM Consensus Cognitive Battery. RP had more NSS and ND than FDR in all subitems except disinhibition, information processing speed, working memory, and visual memory. Similarly, FDR presented poorer performance than controls in all subscales except disinhibition, sensory integration, working memory, and visual memory. Six subitems of NSS and ND met the criteria of endophenotype and the three groups were most accurately classified (71.2%) with these subitems working as a composite endophenotype. Moreover, information processing speed, attention, and social cognition were associated with sensory integration in RP and FDR. These findings add evidences that certain subitems of NSS and ND might be the endophenotypes of schizophrenia and integrating these endophenotypes may prove useful in identifying schizophrenia and high-risk individuals. Furthermore, sensory integration and specific cognitive domains covary, hence suggesting an overlap of compromised underlying neural systems.

22q11 microdeletion syndrome and ultra-high risk for psychosis: The role of neurological soft signs as an independent marker of vulnerability for psychosis

AIM

22q11 microdeletion syndrome has an increased risk for psychosis, similar to subjects at ultra-high risk for psychosis. Neurological soft signs are considered an endophenotype of psychotic disorders and a marker of vulnerability to Schizophrenia, consisting of overflow movements, dysrhythmia and speed of timed activities. To date, there are no studies that have evaluated the presence of the neurological soft signs in subjects with 22q11 microdeletion syndrome and there are a few studies that have analysed this issue in subjects at ultra-high risk.

METHODS

We sought to measure neurological soft signs in these two conditions, compared to healthy controls and to analyse the possible correlation between neurological soft signs and positive/negative symptoms both in 22q11 microdeletion syndrome and ultra-high-risk groups. 54 drug-naive patients (29 with 22q11 microdeletion syndrome and 25 at ultra-high risk for psychosis) and 25 healthy controls were evaluated for neurological soft signs.

RESULTS

Both clinical groups showed a greater number of neurological soft signs compared to healthy control, although the two clinical groups did not differ for the number of neurological soft signs. Positive correlation between speed of timed activities and negative symptoms was found in subjects at ultra-high risk.

CONCLUSION

Neurological soft signs could represent a marker of atypical neurodevelopment in the two populations examined. Since we did not found a strong correlation between neurological soft signs and positive/negative symptoms, we suggest that neurological soft signs could be indicators of vulnerability to psychosis independent from the psychopathology.

12-Month stability of neurological soft signs in stabilized patients with schizophrenia

Objective: Neurological soft signs (NSS) are a group of minor non-localizable neurological abnormalities found more often in patients with schizophrenia. The aim of the current study was to investigate their temporal stability and relationship to the overall outcome over a 12-month period. Material and methods: The study sample included 133 stabilized patients suffering from schizophrenia (77 males and 56 females; aged 33.55 ± 11.22 years old). The assessment included the application at baseline and after 12 months of the Neurological Evaluation Scale (NES), and a number of scales assessing the clinical symptoms and adverse effects. The statistical analysis included ANOVA, exploratory t-test and Pearson correlation coefficients with Bonferroni correction. Results: In stabilized patients, NSS are stable over a 12-month period with only the subscale of NES-sensory integration manifesting a significant worsening, while, in contrast, most of the clinical variables improved significantly. There was no relationship of NES scores with the magnitude of improvement. The only significant negative correlation was between NES-motor coordination and Positive and Negative Syndrome Scale-GP change at 1 year. Discussion: The results of the current study suggest that after stabilization of patients with schizophrenia, there are probably two separate components, a 'trait' which is stable over a 12-month period, and a 'degenerative' component with a tendency to worsen probably in parallel with the progression of the illness and in correlation with the worsening of negative symptoms. However, the statistical support of the 'degenerative' component is weak. Significant outcomes Neurological softs signs are stable over a 12-month period, with the exception of 'sensory integration' which manifests significant improvement irrespective of treatment response. They do not respond to treatment with antipsychotics. They do not constitute a prognostic factor to predict improvement over a period of 1 year. Neurological soft signs constitute a trait symptom of schizophrenia which is stable though time. Limitations All the subjects have been previously hospitalized which may represent a more severe form of schizophrenia. Also, all patients were under antipsychotic and some also under benzodiazepine medications. Patients with comorbid somatic disorders were excluded which may decrease generalizability of results.

Risk Model Assessment in Early-Onset and Adult-Onset Schizophrenia Using Neurological Soft Signs

Age at onset is one of the most important clinical features of schizophrenia that could indicate greater genetic loadings. Neurological soft signs (NSS) are considered as a potential endophenotype for schizophrenia. However, the association between NSS and different age-onset schizophrenia still remains unclear. We aimed to compare risk model in patients with early-onset schizophrenia (EOS) and adult-onset schizophrenia (AOS) with NSS. This study included 262 schizophrenia patients, 177 unaffected first-degree relatives and 243 healthy controls. We estimated the discriminant abilities of NSS models for early-onset schizophrenia (onset age < 20) and adult-onset schizophrenia (onset age ≥ 20) using three data mining methods: artificial neural networks (ANN), decision trees (DT) and logistic regression (LR). We then assessed the magnitude of NSS performance in EOS and AOS families. For the four NSS subscales, the NSS performance were greater in EOS and AOS families compared with healthy individuals. More interestingly, there were significant differences found between patients' families and control group in the four subscales of NSS. These findings support the potential for neurodevelopmental markers to be used as schizophrenia vulnerability indicators. The NSS models had higher discriminant abilities for EOS than for AOS. NSS were more accurate in distinguishing EOS patients from healthy controls compared to AOS patients. Our results support the neurodevelopmental hypothesis that EOS has poorer performance of NSS than AOS. Hence, poorer NSS performance may be imply trait-related NSS feature in EOS.

Antipsychotics Do Not Influence Neurological Soft Signs in Children and Adolescents at Ultra-High Risk for Psychosis: A Pilot Study

OBJECTIVE

Ultra-high risk for psychosis (UHR) is considered as the condition that temporally precedes the onset of psychotic symptoms. In addition to the core symptoms, patients with schizophrenia show motor abnormalities, also known as neurological soft signs (NSS), that are considered an endophenotype for psychotic disorders and particularly for schizophrenia. Antipsychotic medications do not appear to influence NSS in individuals with schizophrenia. However, NSS in UHR subjects have been poorly studied and, to date, we do not know what effects antipsychotics have in early treated UHR subjects. Therefore, we evaluated NSS in treated UHR subjects in comparison with drug-naive UHR subjects and a group of healthy control subjects and the effect of pharmacological treatment on early treated UHR children and adolescents.

PATIENTS AND METHODS

Fifteen UHR subjects receiving pharmacological treatment, 15 drug-naive UHR subjects, and 25 healthy control subjects were evaluated for NSS to analyze any differences between clinical subjects and healthy controls and to evaluate the effect of antipsychotic medications in early treated UHR subjects.

RESULTS

Both clinical groups showed a greater number of NSS compared with the healthy control subjects. However, no significant differences in NSS were found between treated and drug-naive UHR subjects.

CONCLUSIONS

Consistent with what has been observed in the population of patients with a first psychotic episode and/or with schizophrenia, our results support the conclusion that antipsychotic medications do not influence NSS in children and adolescents who are at high risk for psychosis.

Neurological soft signs in familial and sporadic schizophrenia

OBJECTIVE

Neurological soft signs (NSS) are a group of minor non-localizable neurological abnormalities found more often in patients with schizophrenia. The aim of the current study was investigate whether there is any difference in their manifestation in familial vs. sporadic schizophrenia.

MATERIAL AND METHODS

The study sample included 120 patients suffering from schizophrenia according to DSM-5 (71 males and 49 females; aged 32.79 ± 11.11 years old) and 110 normal controls (57 males and 53 females; aged 33.38 ± 10.14 years old). The assessment included the Neurological Evaluation Scale (NES) and the detailed investigation family history. The statistical analysis included exploratory Analysis of Covariance.

RESULTS

The results of the current study suggest that NSS are more frequent in familial cases of schizophrenia and are even more pronounced in cases with family history of psychosis in either first or second degree relatives.

DISCUSSION

Overall the results suggest the presence of a spectrum of increasing severity from healthy controls to sporadic cases, to cases with non-psychotic family history and eventually to cases with psychotic family history, rather than a categorical distribution.

Neurological soft signs in bipolar disorder in comparison to healthy controls and schizophrenia: A meta-analysis

Neurological soft signs (NSS) are subtle deficits in motor coordination, sensory integration, and sequencing of complex motor acts. Increased NSS is a well-established feature of patients with schizophrenia but a relatively smaller number of studies have investigated NSS in bipolar disorder (BD). Some authors but not others suggested that NSS can distinguish schizophrenia from BD. We conducted a meta-analysis of 18 studies to quantitatively review NSS in BD in comparison to schizophrenia and healthy controls. The current meta-analysis compared NSS scores of 725 BD patients and 634 healthy controls, and 391 BD and 471 schizophrenia patients. Patients with BD had significantly higher NSS scores (d = 1.14, CI = 0.89-1.44) than healthy controls and increased scores in BD was evident in all aspects of NSS (d = 0.88-0.99). BD was associated with a less severe increase in NSS compared to schizophrenia, however, between-group difference was modest (d = 0.42, CI = 0.18-0.65). The results of this meta-analysis demonstrated that BD is characterized by a robust increase in NSS which is only moderately less severe than schizophrenia. Increased NSS is a common feature of both disorders.

Neurological soft signs significantly differentiate schizophrenia patients from healthy controls

OBJECTIVE

Neurological soft signs (NSS) are a group of minor non-localisable neurological abnormalities found more often in patients with schizophrenia. The aim of the current study was to test for the effect of gender, age, parental age, age at onset and clinical symptomatology on NSS.Material and methodsThe study sample included 133 patients suffering from schizophrenia according to DSM-IV-TR (77 males and 56 females; aged 33.55±11.22 years old) and 122 normal controls (66 males and 56 females; aged 32.89±9.91 years old). The assessment included the Neurological Evaluation Scale (NES), and a number of scales assessing the clinical symptoms and adverse effects especially extrapyramidal. The statistical analysis included exploratory t-test, simple linear regression analysis, analysis of covariance and the calculation of correlation coefficients.

RESULTS

The results of the current study confirm that NSS are more frequent in patients with schizophrenia in comparison with normal controls (Wilks=0.622, p<0.0001), but do not support an effect of gender, age, age at onset, paternal or maternal age, education, medication status or clinical subtype of schizophrenia on NES scores.DiscussionOverall these results suggest that NSS constitute an independent (from the rest of symptoms), core (present in the vast majority of patients) and trait (unrelated to age and probably to the stage of schizophrenia) symptom of schizophrenia which could be of value in the clinical assessment and research of schizophrenia. Overall these results are not in full accord with the literature, but they could serve to fill in gaps and inconsistencies observed so far.

Neurological soft signs in first-episode schizophrenia: State- and trait-related relationships to psychopathology, cognition and antipsychotic medication effects

BACKGROUND

Neurological soft signs (NSS) are proposed to represent both state- and trait-related features of schizophrenia.

METHOD

We assessed the course of NSS with the Neurological Evaluation Scale (NES) over 12months of standardised treatment in 126 patients with first-episode schizophrenia, schizophreniform or schizoaffective disorder, and evaluated their state- and trait-related associations with psychopathology, functionality, cognition and antipsychotic treatment. We considered change scores from baseline to be state-related and endpoint scores to be trait-related.

RESULTS

Significant effects for time were recorded for all NSS domains. For state-related change-scores greater improvements in sensory integration were predicted by more improvement in working memory (p=0.01); greater improvements in motor sequencing scores were predicted by more improvement in working memory (p=0.005) and functionality (p=0.005); and greater improvements in NES Total score were predicted by more improvement in disorganised symptoms (p=0.02). There were more substantial associations between trait-related endpoint scores than for state-related change scores. For endpoint scores lower composite cognitive score predicted poorer sensory integration (p=0.001); higher Parkinsonism score predicted poorer motor co-ordination (p=0.0001); lower composite cognitive score (p=0.001) and higher Parkinsonism score (p=0.005) predicted poorer motor sequencing; higher Parkinsonism score (p=0.0001) and disorganised symptoms (p=0.04), and lower composite cognitive score (p=0.0007) predicted higher NES total score.

CONCLUSIONS

NSS improved with treatment, but were weakly associated with improvements in psychopathology. Studies investigating NSS as trait-markers should ensure that patients have been optimally treated at the time of testing, and should take possible effects of extrapyramidal symptoms into account.

Neurological soft signs, but not theory of mind and emotion recognition deficit distinguished children with ADHD from healthy control

Attention Deficit Hyperactivity Disorder (ADHD) is associated with social cognition impairment, executive dysfunction and motor abnormalities, consisting in the persistence of neurological soft signs (NSS). Theory of mind (ToM) and emotion recognition (ER) deficit of children with ADHD have been interpreted as a consequence of their executive dysfunction, particularly inhibitory control deficit. To our knowledge, there are not studies that evaluate the possible correlation between the ToM and ER deficit and NSS in the population with ADHD, while this association has been studied in other psychiatric disorders, such as schizophrenia. Therefore, the aim of this study was to evaluate ToM and ER and NSS in a sample of 23 drug-naïve children with ADHD and a sample of 20 healthy children and the possible correlation between social cognition dysfunction and NSS in ADHD. Our findings suggest that ToM and ER dysfunction is not a constant feature in the population with ADHD, while NSS confirmed as a markers of atypical neurodevelopment and predictors of the severity of functional impairment in children with ADHD.

Impairments of motor function among children with a familial risk of schizophrenia or bipolar disorder at 7 years old in Denmark: an observational cohort study

BACKGROUND

Owing to the genetic overlap between schizophrenia and bipolar disorder, we aimed to assess domain-specific motor aberrations and disorder specificity among 7-year-old children with a familial risk of schizophrenia or bipolar disorder by comparing children in familial risk groups with each other and with children not in these risk groups.

METHODS

In the Danish High Risk and Resilience Study, we established a cohort of 7-year-old children with no, one, or two parents with schizophrenia or bipolar disorder in Denmark between Jan 1, 2013, and Jan 31, 2016. We matched children of parents diagnosed with schizophrenia to children of parents without schizophrenia on the basis of their home address, age, and sex. Even though we did not match children of parents with bipolar disorder directly to controls because of resource constraints, we only recruited children into the three groups who did not differ in terms of age, sex, and urbanicity. We investigated motor function in children using the Movement Assessment Battery for Children-Second Edition. Motor function raters were masked to participants' clinical risk status during assessments. We assessed the effects of familial risk group in a mixed-model analysis with repeated measures with an unstructured variance component matrix.

FINDINGS

We studied 514 children (198 [39%] children of parents with schizophrenia, 119 [23%] of parents with bipolar disorder, and 197 [38%] of parents without schizophrenia or bipolar disorder). Children of parents with schizophrenia showed impaired motor performance compared with those of parents without in the subdomains of manual dexterity (mean difference -1·42 [95% CI -2·08 to -0·77]; p<0·0001) and balance (-1·38 [-2·03 to -0·72]; p<0·0001), but not of aiming and catching (-0·39 [-0·97 to 0·19]; p=0·18). Children of parents with bipolar disorder did not show any significant difference in motor performance to children of parents without in the subdomains of manual dexterity (-0·69 [-1·44 to 0·07]; p=0·08), balance (-0·68 [-1·44 to 0·08]; p=0·08), and aiming and catching (-0·36 [-1·03 to 0·31]; p=0·29). Comparison of familial risk groups of mental disorders revealed no significant differences in the subdomains of manual dexterity (-0·74 [-1·49 to 0·02]; p=0·06), balance (-0·70 [-1·46 to 0·06]; p=0·07), or aiming and catching (-0·03 [-0·70 to 0·63]; p=0·92).

INTERPRETATION

Motor abnormalities in children with a familial risk of schizophrenia are specific at 7 years of age with respect to fine motor function and balance, but non-specific with respect to familial risk of bipolar disorder. Clinicians should be aware of motor symptoms and refer children with definite motor problems (below the fifth percentile) to a child physiotherapist.

FUNDING

Mental Health Services of the Capital Region of Denmark, Aarhus University, and the Lundbeck Foundation Initiative for Integrative Psychiatric Research.

Cerebellar Symptoms Are Associated With Omission Errors and Variability of Response Time in Children With ADHD

OBJECTIVE

We examined the presence of cerebellar symptoms in ADHD and their association with behavioral markers of this disorder.

METHOD

Sixty-two children with ADHD and 62 typically developing (TD) children were examined for cerebellar symptoms using the ataxia rating scale and tested using Conners' Continuous Performance Test.

RESULTS

Children with ADHD had significantly more cerebellar symptoms compared with the TD children. Cerebellar symptom scores decreased with age in the ADHD group; in the TD group remained stable. In both groups, cerebellar symptoms were associated with parent-rated hyperactive/impulsive symptoms, variability of response time standard error (RT-SE) and increase of RT-SE as the test progresses. More variables were associated with cerebellar symptoms in the ADHD group including omission errors, overall RT-SE and its increase for prolonged interstimulus intervals.

CONCLUSION

Our results highlight the importance of research into motor functions in children with ADHD and indicate a role for cerebellar impairment in this disorder.

Neurological soft signs in euthymic bipolar I patients: A comparative study with healthy siblings and controls

Neurological Soft Signs (NSS) are endophenotypic markers widely studied in schizophrenia and remain poorly evaluated in bipolar disorder. The aims of this paper were to determine the prevalence and scores of NSS in bipolar I patients, compared to healthy siblings and controls and to explore correlations with socio-demographic and clinical features of patients. This was a case-control study comparing 92 euthymic bipolar I patients, 44 of their healthy siblings and 60 control subjects. The neurological assessment was performed through the NSS scale validated by Krebs et al. (2000). Bipolar I patients were also assessed with the Bech-Rafaelsen Mania Scale (MAS), the Hamilton Depression Rating Scale (HDRS) and the Global Assessment of Functioning (GAF). The raters were not blinded to groups. The prevalence and the total score of NSS were significantly higher in bipolar I patients compared to their healthy siblings and controls. The sibling group had significantly higher NSS prevalence and total score than controls. No correlation was found between NSS total score and socio-demographic and clinical features of patients, except a negative correlation with the school level and the GAF score. In conclusion, bipolar I patients have motor and sensory signs, which are unrelated to their clinical features.

Neurological and cerebellar soft signs do not discriminate schizophrenia from bipolar disorder patients

Patients with schizophrenia (SZ) and bipolar disorder (BD) share subtle motor abnormalities called the neurological soft signs (NSS). Since in both diseases there is evidence for alterations in cerebellar functions, structure and connectivity, we expected that the cerebellar soft signs (CSS), analogue of NSS focusing strictly on cerebellar symptoms, would be also a common trait in SZ and BD. We examined 30 patients with BD, 30 patients with SZ and 28 control subjects using the Neurological Evaluation Scale (NES, for NSS) and International Cooperative Ataxia Rating Scale (ICARS, for CSS). SZ and BD did not differ in total and subscales' scores in both NES and ICARS. Subscale analysis revealed that SZ performed significantly worse than controls in all the subscales of both NES and ICARS. BD patients scored significantly worse than controls in all NES subscales and in oculomotor and kinetic subscales of the ICARS, while other ICARS subscales did not differentiate those two groups. To our knowledge this is the first study to show that CSS constitute common symptoms in BD and SZ. We recommend a special focus on those diseases in further research regarding structural and functional changes of cerebellum and their clinical outcome.

Course of neurological soft signs in first-episode schizophrenia: Relationship with negative symptoms and cognitive performances

This prospective study examined the course of neurological soft signs (NSS) in patients with first-episode schizophrenia and its relationship with negative symptoms and cognitive functions. One hundred and forty-five patients with first-episode schizophrenia were recruited, 29 were classified as having prominent negative symptoms. NSS and neuropsychological measures were administered to all patients and 62 healthy controls at baseline. Patients were then followed-up prospectively at six-month intervals for up to a year. Patients with prominent negative symptoms exhibited significantly more motor coordination signs and total NSS than patients without prominent negative symptoms. Patients with prominent negative symptoms performed worse than patients without negative symptoms in working memory functions but not other fronto-parietal or fronto-temporal functions. Linear growth model for binary data showed that the prominent negative symptoms were stable over time. Despite general improvement in NSS and neuropsychological functions, the prominent negative symptoms group still exhibited poorer motor coordination and higher levels of NSS, as well as poorer working memory than patients without prominent negative symptoms. Two distinct subtypes of first-episode patients could be distinguished by NSS and prominent negative symptoms.

Neurology issues in schizophrenia

Schizophrenia ranks among the leading causes of disability worldwide. The presence of neurological signs co-occurring with the psychiatric symptoms is indicative of an organic brain pathology. In the present article, we review the current literature on neurology issues in schizophrenia. Firstly, common neurological signs found in patients with schizophrenia (neurological soft signs and smell abnormalities) and their association with imaging findings are reviewed. Secondly, the significant association of schizophrenia with epilepsy and stroke is described as well as the absent association with other organic brain diseases such as multiple sclerosis. Thirdly, we discuss the potential role of NMDA receptor antibodies in schizophrenia. Fourthly, neurological side effects of antipsychotic drugs and their treatment are reviewed; and lastly, we discuss neurocognitive deficits in patients with schizophrenia and their treatment. The focus of the review remains on articles with relevance to the clinician.

Neurological soft signs in the clinical course of schizophrenia: results of a meta-analysis

Neurological soft signs (NSS) comprise subtle deficits in sensory integration, motor coordination, and sequencing of complex motor acts, which are typically observed in the majority of schizophrenia patients, including chronic cases and neuroleptic-naïve first-episode patients. However, recent studies clearly demonstrate that NSS are not a static feature of schizophrenia but vary in the clinical course of the disorder. This effect was investigated in a meta-analysis based on 17 longitudinal studies published between 1992 and 2012. Studies included between 10 and 93 patients with schizophrenia spectrum disorders (total number 787) with follow-up periods between 2 and 208 weeks. Beside the Neurological Examination Scale, the Cambridge Neurological Inventory and the Heidelberg NSS Scale were used to assess NSS. All but three studies found NSS to decrease in parallel with remission of psychopathological symptoms. This effect was more pronounced in patients with a remitting compared to a non-remitting, chronic course (Cohen's d 0.81 vs. 0.15) and was significantly correlated with length of the follow-up period (r = -0.64) but not with age (r = 0.28). NSS scores did not decrease to the level typically observed in healthy controls. From a clinical perspective, NSS may therefore be used to identify subjects at risk to develop schizophrenia and to monitor disease progression.

Luria revisited: complex motor phenomena in first episode schizophrenia and schizophrenia spectrum disorders

Patients with schizophrenia frequently exhibit motor deficits. However, to date, there are no studies comparing motor performance in first episode patients with schizophrenia and schizophrenia spectrum disorders (SSD; e.g. schizoaffective and brief psychosis). Participants comprised 57 first episode patients with schizophrenia, 32 first episode patients with SSD, and 51 healthy controls who underwent neuropsychological testing based on Luria׳s systematic approach, including the following tests on complex motor sequencing: the Fist-Edge-Palm (FEP) test and the bimanual probe (BP). Schizophrenia patients performed worse than SSD patients in FEP and BP, and both patient groups showed decreased scores compared to healthy controls. Furthermore, we found that a higher proportion of schizophrenia cases failed to correct their motor performance and needed external error correction, while SSD cases exhibited a higher proportion of self-correction in FEP and in BP. Lack of insight and poor executive functioning correlated with motor performance in schizophrenia, while impulse control and difficulties in abstract thinking were related to motor performance in schizophrenia spectrum disorder. Thus, psychomotor impairments appear already in first episode patients with schizophrenia and differ from impairments in SSD. Especially the inability to self-correct errors may be characteristic of schizophrenia, suggesting that impairments in error monitoring are related to psychomotor dysfunction in schizophrenia.

[Neurological soft signs in early onset schizophrenia]

INTRODUCTION

Neurological soft signs (NSS) are subtle neurological abnormalities that cannot be linked to the achievement of a specific region of the central nervous system and which are not part of a particular neurological syndrome. These signs are observed in the case of diseases supporting the neurodevelopmental model such as schizophrenia in general and its early form defined notably by an age of onset of less than 18 years. Indeed, the NSS belong to a set of clinical, cognitive, electrophysiological and neuroanatomical markers reflecting neurodevelopmental brain abnormalities in patients with schizophrenia.

OBJECTIVE

The objectives of our study were to determine the prevalence, the scores, and the nature of neurological soft signs (NSS) in adolescent patients suffering from early onset schizophrenia diagnosis in comparison to healthy controls, and to explore the correlations between NSS and the demographic, clinical and therapeutic features of these patients.

MATERIALS AND METHODS

Twelve adolescents were recruited in the Child Psychiatry Department at the Razi Hospital (Tunisia), with the diagnosis of schizophrenia according to the DSM-IV supplemented by the Kiddie SAD PL. They were matched by age and educational level with twelve healthy controls without psychiatric family or personal history. The clinical status of the patients was assessed using the Positive and Negative Syndrome Scale (PANSS). Neurological soft signs (NSS) were rated with the Neurological Soft Signs Examination (NSSE) by Krebs et al. (2000) for the two groups. This scale is composed of 23 items exploring motor coordination, motor integrative function, sensory integration, involuntary movements and quality of lateralization.

RESULTS

The mean age of our population was 14.7 years. The average age of onset of the disease was 12.2 years. The sex-ratio was 1.4. Educational level was 7.4 years. The PANSS mean total score was 74.3. The mean daily dose, in chlorpromazine equivalents, was 523.9 mg/day. Four patients received a strict monotherapy of antipsychotics, while the other patients were receiving an association of two neuroleptics. The prevalence of NSS was 100% (cut-off point=11) with a mean total score of 29.3±4.1. The highest score was for the motor coordination (10.1). As for the control group, the mean total score was 7±1.3. A highly significant difference was found between patients and controls for all sub-scores of NSS. Negative correlations were found in patients, between age and neurological soft signs total score (P=0.05; r=-0.57) and also with sensory integration score (P=0.04; r=-0.58). The NSS total score was also correlated with low educational level (P=0.03; r=-0.61). There was no correlation between neurological soft signs scores and PANSS scores or the daily dose of antipsychotics.

CONCLUSION

The prevalence and NSS scores are high among young people with early onset schizophrenia diagnosis illustrating the existence of structural abnormalities of the brain, themselves consequences of early neurodevelopmental disturbances, which would support the neurodevelopmental hypothesis concerning this pathology.

Differential neurodevelopmental trajectories in patients with early-onset bipolar and schizophrenia disorders

Schizophrenia and bipolar disorders share not only clinical features but also some risk factors such as genetic markers and childhood adversity, while other risk factors such as urbanicity and obstetric complications seem to be specific to schizophrenia. An intriguing question is whether the well-established abnormal neurodevelopment present in many children and adolescents who eventually develop schizophrenia is also present in bipolar patients. The literature on adult bipolar patients is controversial. We report data on a subgroup of patients with pediatric-onset psychotic bipolar disorder who seem to share some developmental trajectories with patients with early-onset schizophrenia. These early-onset psychotic bipolar patients have low intelligence quotient, more neurological signs, reduced frontal gray matter at the time of their first psychotic episode, and greater brain changes than healthy controls in a pattern similar to early-onset schizophrenia cases. However, patients with early-onset schizophrenia seem to have more social impairment, developmental abnormalities (eg, language problems), and lower academic achievement in childhood than early-onset bipolar patients. We suggest that some of these abnormal developmental trajectories are more related to the phenotypic features (eg, early-onset psychotic symptoms) of these 2 syndromes than to categorically defined Diagnostic and Statistical Manual of Mental Disorders disorders.

Are neurological soft signs pre-existing markers in individuals with an at-risk mental state for psychosis?

Neurological soft signs (NSS) are more common in schizophrenic psychoses and in genetically high-risk individuals than in healthy controls. But nothing is known so far regarding individuals with a clinical at-risk mental state (ARMS). The goals of our study therefore were (a) to compare the NSS frequency in ARMS individuals to that of first-episode psychosis (FEP) patients and (b) to test whether NSS could predict the transition to psychosis. Neurological soft signs were assessed using a shortened version of the Neurological Evaluation Scale (NES). Fifty-three ARMS individuals (16 with later transition to psychosis=ARMS-T, and 37 without transition=ARMS-NT) and 27 FEP patients were recruited through the Basel Early Detection Clinic FePsy. Of the FEP patients 37% showed NSS. We found no significant differences between FEP and ARMS-T patients or between ARMS-NT and ARMS-T. Our findings of NSS being present already before transition to psychosis to the same extent as after transition provide further support to the neurodevelopmental hypothesis of schizophrenic psychoses. Furthermore, our findings might indicate that ARMS-NT individuals also suffer from some sort of neurodevelopmental abnormalities.

Cognitive profiles of three clusters of patients with a first-episode psychosis

OBJECTIVE

The primary objective was to identify specific groups of patients with a first-episode psychosis based on family history, obstetric complications, neurological soft signs, and premorbid functioning. The secondary objective was to relate these groups with cognitive variables.

METHOD

A total of 62 first-episode psychoses were recruited from adult and child and adolescent mental health services. The inclusion criteria were patients between 7 and 65 years old (real range of the samples was 13-35 years old), two or more psychotic symptoms and less than one year from the onset of the symptoms. Premorbid functioning (PAS), soft signs (NES), obstetric complications and a neuropsychological battery (CPT, TMTA/TMTB, TAVEC/TAVECI, Stroop, specific subtest of WAIS-III/WISC-IV) were administered.

RESULTS

We found three clusters: 1) higher neurodevelopment contribution (N=14), 2) higher genetic contribution (N=30), and 3) lower neurodevelopment contribution (N=18). Statistical differences were found between groups in TMTB, learning curve of the TAVEC, digits of the WAIS and premorbid estimated IQ, the cluster 1 being the most impaired.

CONCLUSIONS

A cluster approach could differentiate several groups of patients with different cognitive performance. Neuropsychological interventions, as cognitive remediation, should be addressed specifically to patients with more impaired results.

Enhanced persistency of resting and active periods of locomotor activity in schizophrenia

Patients with schizophrenia frequently exhibit behavioral abnormalities associated with its pathological symptoms. Therefore, a quantitative evaluation of behavioral dynamics could contribute to objective diagnoses of schizophrenia. However, such an approach has not been fully established because of the absence of quantitative biobehavioral measures. Recently, we studied the dynamical properties of locomotor activity, specifically how resting and active periods are interwoven in daily life. We discovered universal statistical laws ("behavioral organization") and their alterations in patients with major depressive disorder. In this study, we evaluated behavioral organization of schizophrenic patients (n = 19) and healthy subjects (n = 11) using locomotor activity data, acquired by actigraphy, to investigate whether the laws could provide objective and quantitative measures for a possible diagnosis and assessment of symptoms. Specifically, we evaluated the cumulative distributions of resting and active periods, defined as the periods with physical activity counts successively below and above a predefined threshold, respectively. Here we report alterations in the laws governing resting and active periods; resting periods obeyed a power-law cumulative distribution with significantly lower parameter values (power-law scaling exponents), whereas active periods followed a stretched exponential distribution with significantly lower parameter values (stretching exponents), in patients. Our findings indicate enhanced persistency of both lower and higher locomotor activity periods in patients with schizophrenia, probably reflecting schizophrenic pathophysiology.