Neurological soft signs in non-psychotic first-degree relatives of patients with schizophrenia: a systematic review and meta-analysis

Neuropsychology and Neurobiology of Negative Schizotypy: A Selective Review

Schizotypy refers to a latent personality organization that reflects liability to schizophrenia. Because schizotypy is a multidimensional construct, people with schizotypy vary in behavioral and neurobiological features. In this article, we selectively review the neuropsychological and neurobiological profiles of people with schizotypy, with a focus on negative schizotypy. Empirical evidence is presented for alterations of neuropsychological performance in negative schizotypy. We also cover the Research Domain Criteria domains of positive valence, social process, and sensorimotor systems. Moreover, we systematically summarize the neurobiological correlates of negative schizotypy at the structural, resting-state, and task-based neural levels, as well as the neurochemical level. The convergence and inconsistency of the evidence are critically reviewed. Regarding theoretical and clinical implications, we argue that negative schizotypy represents a useful organizational framework for studying neuropsychology and neurobiology across different psychiatric disorders.

Cortical alterations in relatives of patients with bipolar disorder: A review of magnetic resonance imaging studies

INTRODUCTION

Bipolar disorder (BD) is a severe mental disorder characterized by high heritability rates. Widespread brain cortical alterations have been reported in BD patients, mostly involving the frontal, temporal and parietal regions. Importantly, also unaffected relatives of BD patients (BD-RELs) present abnormalities in cortical measures, which are not influenced by disease-related factors, such as medication use and illness duration. Here, we collected all available evidence on cortical measures in BD-RELs to further our knowledge on the potential cortical alterations associated with the vulnerability and the resilience to BD.

METHODS

A search on PubMed, Web of Science and Scopus was performed to identify neuroimaging studies exploring cortical alterations in BD-RELs, including cortical thickness (CT), surface area (SA), gyrification (GI) and cortical complexity. Eleven studies were included. Of these, five assessed CT, five examined CT and SA and one explored CT, SA and GI.

RESULTS

Overall, a heterogeneous pattern of cortical alterations emerged. The areas more consistently linked with genetic liability for BD were the prefrontal and sensorimotor regions. Mixed evidence was reported in the temporal and cingulate areas.

LIMITATIONS

The small sample size and the heterogeneity in terms of methodologies and the characteristics of the participants limit the generalizability of our results.

CONCLUSIONS

Our findings suggest that the genetic liability for BD is related to reduced CT in the prefrontal cortex, which might be a marker of risk for BD, and increased CT within the sensorimotor cortex, which could represent a marker of resilience.

Neurological soft signs and schizophrenia

Neurological soft signs (NSS) are likely to represent abnormal neurodevelopment and aberration in neural maturation and connectivity. They may not be unique to schizophrenia, but they appear to be a trait characteristic in psychosis and therefore could serve as an objective measure for the assessment of serious psychiatric disorder in the prodromal phase, at onset, and along the course of the disease. Evidence so far proposes that NSS are independent of antipsychotic treatment and therefore constitute a trait symptom, independent of the illness stage and medication. Somatomotor and somatosensory regions, spatial orientation, and visual processing areas, cerebellum, and basal ganglia are implicated as possible structural substrates of NSS. Several studies have examined the relationship between NSS and schizophrenia positive, negative symptoms and deficit syndrome; however, results have been so far ambiguous. Neurocognitive symptoms have been moderately related to NSS suggesting that neurocognitive deficits may contribute to the construct of NSS. Regardless of the fact that NSS are not unique to schizophrenia but extend across to the schizotypy continuum, they may help identify individuals at risk of developing schizophrenia later in life.

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 Impact of Antipsychotic Treatment on Neurological Soft Signs in Patients with Predominantly Negative Symptoms of Schizophrenia

Schizophrenia is a complex and incompletely elucidated pathology that affects sensorimotor function and also produces numerous therapeutic challenges. The aims of this cross-sectional study were to identify the profile of neurological soft signs (NSS) in patients with predominantly negative symptoms of schizophrenia (PNS) compared with patients with schizophrenia who do not present a predominance of negative symptoms (NPNS) and also to objectify the impact of treatment on the neurological function of these patients. Ninety-nine (n = 99; 56 females and 43 males) patients diagnosed with schizophrenia according to DSM-V were included; these patients were undergoing antipsychotic (4 typical antipsychotics, 86 atypical antipsychotics, and 9 combinations of two atypical antipsychotics) or anticholinergic treatment (24 out of 99) at the time of evaluation, and the PANSS was used to identify the patients with predominantly negative symptoms (n = 39), the Neurological Evaluation Scale (NES) was used for the evaluation of neurological soft signs (NSS), and the SAS was used for the objectification of the extrapyramidal side effects induced by the neuroleptic treatment, which was converted to chlorpromazine equivalents (CPZE). The study's main finding was that, although the daily dose of CPZE did not represent a statistically significant variable, in terms of neurological soft signs, patients with PNS had higher rates of NSS.

Structural network alterations and their association with neurological soft signs in schizophrenia: Evidence from clinical patients and unaffected siblings

BACKGROUND

Grey matter abnormalities and neurological soft signs (NSS) have been found in schizophrenia patients and their unaffected relatives. Evidence suggested that NSS are associated with grey matter morphometrical alterations in multiple regions in schizophrenia. However, the association between NSS and structural abnormalities at network level remains largely unexplored, especially in the schizophrenia and unaffected siblings.

METHOD

We used source-based morphometry (SBM) to examine the association of structural brain network characteristics with NSS in 62 schizophrenia patients, 25 unaffected siblings, and 60 healthy controls.

RESULTS

Two components, namely the IC-5 (superior temporal gyrus, inferior frontal gyrus and insula network) and the IC-10 (parahippocampal gyrus, fusiform, thalamus and insula network) showed significant grey matter reductions in schizophrenia patients compared to healthy controls and unaffected siblings. Further association analysis demonstrated separate NSS-related grey matter covarying patterns in schizophrenia, unaffected siblings and healthy controls. Specifically, NSS were negatively associated with IC-1 (hippocampus, caudate and thalamus network) and IC-5 in schizophrenia, but with IC-3 (caudate, superior and middle frontal cortices network) in unaffected siblings and with IC-5 in healthy controls.

CONCLUSION

Our results confirmed the key cortical and subcortical network abnormalities and NSS-related grey matter covarying patterns in the schizophrenia and unaffected siblings. Our findings suggest that brain regions implicating genetic liability to schizophrenia are partly separated from brain regions implicating neural abnormalities.

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.

Characterizing the sensorimotor domain in schizophrenia spectrum disorders

The rapidly evolving field of sensorimotor neuroscience reflects the scientific and clinical relevance of sensorimotor abnormalities as an intrinsic component of the disease process, e.g., in patients with schizophrenia spectrum disorders (SSD). Despite previous efforts, however, prevalence rates and relationships between different categories of sensorimotor abnormalities in SSD patients are still subject of ongoing debate. In this study, we examined five different categories of the sensorimotor domain (Neurological soft signs (NSS), parkinsonism, catatonia, akathisia, and tardive dyskinesia) according to well-established clinical ratings scales and the respective cut-off criteria in a sample of 131 SSD patients. We used a collection of statistical methods to better understand prevalence, overlap and heterogeneity, as well as psychopathological and cognitive correlates of sensorimotor abnormalities. 97.7% of the SSD patients considered by this study exhibited at least one categorically defined sensorimotor abnormality that tended to co-vary within three different sensorimotor subgroups (moderate, hyperkinetic and hypokinetic). Finally, hyperkinetic and hypokinetic groups differed significantly in their neurocognitive performance compared with the moderate group. The results suggest different patterns of clinical overlap, highlight the relationship between sensorimotor and cognitive domain and provide clues for further neurobiological studies.

Investigation of structural brain correlates of neurological soft signs in individuals at ultra-high risk for psychosis

Increased severity of neurological soft signs (NSS) in schizophrenia have been associated with abnormal brain morphology in cerebello-thalamo-cortical structures, but it is unclear whether similar structures underlie NSS prior to the onset of psychosis. The present study investigated the relationship between severity of NSS and grey matter volume (GMV) in individuals at ultra-high risk for psychosis (UHR) stratified for later conversion to psychosis. Structural T1-weighted MRI scans were obtained from 56 antipsychotic-naïve UHR individuals and 35 healthy controls (HC). The UHR individuals had follow-up data (mean follow-up: 5.2 years) to ascertain clinical outcome. Using whole-brain voxel-based morphometry, the relationship between NSS and GMV at baseline was assessed in UHR, HC, as well as individuals who later transitioned (UHR-P, n = 25) and did not transition (UHR-NP, n = 31) to psychosis. NSS total and subscale scores except motor coordination were significantly higher in UHR compared to HC. Higher signs were also found in UHR-P, but not UHR-NP. Total NSS was not associated with GMV in the whole sample or in each group. However, in UHR-P individuals, greater deficits in sensory integration was associated with lower GMV in the left cerebellum, right insula, and right middle frontal gyrus. In conclusion, NSS are present in UHR individuals, particularly those who later transitioned to a psychotic disorder. While these signs show little overall variation with GMV, the association of sensory integration deficits with lower GMV in UHR-P suggests that certain brain areas may be implicated in the development of specific neurological abnormalities in the psychosis prodrome.

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.

Different trajectories of neurological soft signs progression between treatment-responsive and treatment-resistant schizophrenia patients

Schizophrenia patients exhibit subtle and non-localizing neurological abnormalities, known as neurological soft signs (NSS). Life-span evidence suggests that NSS vary along the course of schizophrenia. An association between NSS and treatment response has been proposed, suggesting that NSS reflect the underlying neuropathology development in schizophrenia. However, few studies have investigated the relationship between NSS and treatment resistance in first-episode schizophrenia patients. We conducted a longitudinal study on 52 first-episode schizophrenia patients, who were assessed at baseline, the sixth month, and the fifth year using the abridged version of the Cambridge Neurological Inventory. The trajectories of NSS between 29 treatment-responsive patients (with full symptomatic remission) and 23 treatment-resistant patients (who received clozapine) were compared using mixed model ANOVA. We also controlled for the effect of age and estimated IQ, using a mixed ANCOVA model. Although the two schizophrenia groups had comparable NSS at the baseline, their trajectories of NSS differed significantly. Compared with their treatment-responsive counterparts, treatment-resistant schizophrenia patients had worsening of NSS over time. Our findings support the potential utility of NSS in identifying treatment resistance in first-episode schizophrenia. Progressive worsening of NSS in treatment-resistant schizophrenia patients may reflect the development of underlying neuropathology. Further studies using large samples of treatment-resistant schizophrenia patients are needed.

Examination of the Prefrontal Cortex Hemodynamic Responses to the Fist-Edge-Palm Task in Naïve Subjects Using Functional Near-Infrared Spectroscopy

The Fist-Edge-Palm (FEP) task, a manual hand task, has been used to detect frontal dysfunctions in clinical situations: its performance failures are observed in various prefrontal cortex (PFC)-related disorders, including schizophrenia. However, previous imaging studies reported that the performance of the FEP task activated motor-related areas, but not the PFC. Here, we aimed to investigate the relationships between the performance of the FEP task and PFC functions. Hemodynamic activity in the PFC, including the dorsolateral PFC (area 46) and frontal pole (area 10), was recorded. Healthy young subjects performed the FEP task as well as a palm tapping (PT) task (control task) three times. The subjects also completed a Wisconsin Card Sorting Test (WCST) and Schizotypal Personality Scale (STA) questionnaire. We found that hemodynamic activity (Oxy-Hb) in the PFC increased in the first trial of the FEP task but decreased considerably in the second and third trials compared to the PT task. The number of performance errors in the FEP task also decreased in the second and third trials. Error reduction (i.e., learning) in the FEP task between the first and second trials was negatively correlated with schizotypal trait and the number of perseveration errors in the WCST. Furthermore, changes in the PFC hemodynamic activity between the first and second trials were positively correlated with error reduction in the FEP task between the first and second trials, and negatively correlated with the number of perseveration errors in the WCST. These results suggest that learning in the FEP task requires PFC activation, which is negatively associated with perseveration errors in the WCST. The results further suggest that the FEP task, in conjunction with near-infrared spectroscopy, may be useful as a diagnostic method for various disorders with PFC dysfunction.

Neurological Soft Signs Are Associated With Altered Cerebellar-Cerebral Functional Connectivity in Schizophrenia

Cerebellar dysfunction is associated with neurological soft signs (NSS), which is a promising endophenotype for schizophrenia spectrum disorders. However, the relationship between cerebellar-cerebral resting-state functional connectivity (rsFC) and NSS is largely unexplored. Moreover, both NSS and cerebellar-cerebral rsFC have been found to be correlated with negative symptoms of schizophrenia. Here, we investigated the correlations between NSS and cerebellar-cerebral rsFC, explored their relationship with negative symptoms in a main dataset, and validated the significant findings in a replication dataset. Both datasets comprised schizophrenia patients and healthy controls. In schizophrenia patients, we found positive correlations between NSS and rsFC of the cerebellum with the inferior frontal gyrus and the precuneus, and negative correlations between NSS and rsFC of the cerebellum with the inferior temporal gyrus. In healthy controls, NSS scores were positively correlated with rsFC of the cerebellum with the superior frontal gyrus and negatively correlated with rsFC between the cerebellum and the middle occipital gyrus. Cerebellar-prefrontal rsFC was also positively correlated with negative symptoms in schizophrenia patients. These findings were validated in the replication dataset. Our results suggest that the uncoupling of rsFC between the cerebellum and the cerebral cortex may underlie the expression of NSS in schizophrenia. NSS-related cerebellar-prefrontal rsFC may be a potential neural pathway for possible neural modulation to alleviate negative symptoms.

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 (NSS) and brain morphology in patients with chronic schizophrenia and healthy controls

Subtle abnormalities in sensory integration, motor coordination and sequencing of complex motor acts or neurological soft signs (NSS) are characteristic phenomena in patients with schizophrenia at any stage of the illness. Previous MRI studies in schizophrenia found NSS to be associated with cortical, thalamic and cerebellar changes. Since these studies mainly focused on first-episode or recent onset schizophrenia, the cerebral correlates of NSS in chronic schizophrenia remained rather unclear. 49 middle-aged patients with chronic schizophrenia with a mean duration of illness of 20.3 ± 14.0 years and 29 healthy subjects matched for age and sex were included. NSS were examined on the Heidelberg Scale and correlated to grey matter (GM) by using whole brain high resolution magnetic resonance imaging (3 Tesla) with SPM12/CAT12 analyses. As expected, NSS in patients were significantly (p≤0.001) elevated in contrast to healthy controls, a finding, which not only applied to NSS total score, but also to the respective subscales "motor coordination", "sensory integration", "complex motor tasks", "right/left and spatial orientation" and "hard signs". Within the patient group NSS total scores were significantly correlated to reduced GM in right lingual gyrus, left parahippocampal gyrus, left superior temporal gyrus, left thalamus (medial dorsal nucleus) and left posterior lobe of the cerebellum (declive). Respective negative associations could also be revealed for the subscales "motor coordination", "complex motor tasks" and "right/left and spatial orientation". These findings remained significant after FWE-correction for multiple comparisons and were confirmed when years of education, chlorpromazine-equivalents or variables indicating the severity of psychopathology were introduced as additional covariates. According to our results lingual, parahippocampal, superior temporal, inferior and middle frontal gyri, thalamus and cerebellum have to be considered as important sites of NSS in chronic schizophrenia. That these findings only applied for patients but not healthy controls may indicate a different pathogenesis of NSS.

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.

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

Neurological soft signs (NSS) have garnered increasing attention in psychiatric research on motor abnormalities in schizophrenia spectrum disorders (SSD). However, it remains unclear whether the assessment of NSS severity could have been confounded by current antipsychotic dosage. In this study, we recruited 105 patients with SSD that underwent a comprehensive motor assessment evaluating NSS and extrapyramidal motor symptoms (EPMS) by means of standardized instruments. Current antipsychotic dosage equivalence estimates were determined by the classical mean dose method (doses equivalent to 1 mg/d olanzapine). We used multiple regression analyses to describe the relationship between NSS, EPMS and antipsychotic medication. In line with our expectations, current antipsychotic dosage had no significant effects on NSS total score (p = 0.27), abnormal involuntary movements (p = 0.17), akathisia (p = 0.32) and parkinsonism (p = 0.26). Further, NSS total score had a significant effect on akathisia (p = 0.003) and parkinsonism (p = 0.0001, Bonferroni corr.), but only marginal effect on abnormal involuntary movements (p = 0.08). Our results support the notion that NSS are not significantly modulated by current antipsychotic dosage in SSD. The associations between NSS, akathisia and parkinsonism, as revealed by this study, support the genuine rather than medication-dependent origin of particular motor abnormalities in SSD.

Exploring the Relationship of Transdiagnostic Mood and Psychosis Symptom Domains with Motor Dysfunction

BACKGROUND

A number of motor abnormalities have been reported in psychotic disorders, including dyskinesia and psychomotor slowing. There is also evidence for many of the same motor abnormalities in biological first-degree relatives and accruing evidence for motor abnormalities in bipolar disorder. In addition to motor dysfunction, there are also shared symptom domains amongst these populations.

OBJECTIVES

We explored the associations of (1) current and lifetime psychosis and mood symptom domains and (2) domains of psychosis proneness with various domains of motor function in a transdiagnostic sample (n = 149).

METHOD

Individuals with schizophrenia, schizoaffective disorder, or bipolar disorder, biological first-degree relatives of individuals with a psychotic disorder, and controls completed measures of psychomotor speed and movement fluidity, and neural activity related to motor preparation (stimulus-locked lateralized readiness potential, S-LRP) and execution (response-locked LRP) was assessed using EEG. All participants completed the Brief Psychiatric Rating Scale; patients were additionally assessed for lifetime psychosis and mood episode symptoms, and relatives and controls completed the Chapman psychosis proneness scales.

RESULTS

Multiple regression revealed levels of current negative symptoms and mania were significantly positively associated with psychomotor slowing even after accounting for current antipsychotic medication dosage and duration of illness. S-LRP onset latency was significantly positively associated with magical ideation.

CONCLUSION

Domains of motor function are associated with various mood and psychosis symptom domains in a transdiagnostic sample, which may provide insight into brain abnormalities relevant to the expression of symptoms across disorders.

Looking at Intergenerational Risk Factors in Schizophrenia Spectrum Disorders: New Frontiers for Early Vulnerability Identification?

Offspring of individuals with serious mental illness (SMI) constitute a special population with a higher risk of developing psychiatric disorders, which is also highly prevalent among referrals to child and adolescent mental health services (CAMHS). They often exhibit more or less subclinical conditions of vulnerability, fueled by mutually potentiating combinations of risk factors, such as presumed genetic risk, poor or inadequate affective and cognitive parenting, and low socio-economic status. Despite this evidence, neither specific preventive programs for offspring of parents with SMI are usually implemented in CAMHS, nor dedicated supportive programs for parenting are generally available in adult mental health services (AMHS). Needless to say, while both service systems tend to focus on individual recovery and clinical management (rather than on the whole family system), these blind spots add up to frequent gaps in communication and continuity of care between CAMHS and AMHS. This is particularly problematic in an age-range in which an offspring's vulnerabilities encounter the highest epidemiological peak of incident risk of SMI. This paper offers a clinical-conceptual perspective aimed to disentangle the complex intertwine of intergenerational risk factors that contribute to the risk of developing SMI in offspring, taking schizophrenia spectrum disorders as a paradigmatic example.

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.

Social cognitions in siblings of patients with schizophrenia: a comparison with patients with schizophrenia and healthy controls - a cross-sectional study

BACKGROUND

There are limited number of studies which have evaluated social cognitive deficits among the siblings of patients with schizophrenia.

AIM

This study aimed to evaluate the social cognitive deficits and its correlates among siblings of patients with schizophrenia.

METHODOLOGY

Patients of schizophrenia (N = 34), their siblings (N = 34) and healthy control subjects (N = 31) matched for age, gender, education and intelligence quotient were evaluated on social cognition rating tools in Indian setting (SOCRATIS). Patients were additionally evaluated on Positive and Negative Symptom Scale (PANSS). Siblings were assessed on Comprehensive Assessment for at risk mental state (CAARMS) scale and Short Wisconsin Schizotypy scale. Neurocognitive test battery was applied to all the groups.

RESULTS

Patients with schizophrenia performed the worst and the healthy controls performed the best, with siblings falling intermediate on all the subtests of social cognition (except for externalizing bias and personalized bias) and neurocognition. There were negative correlation between some of the domains of social cognition and various domains of CAARMS. Higher level of schizotypy was associated with higher level of social cognitive deficits.

CONCLUSION

Social cognitive deficits can act as an important endophenotype for estimating the risk of schizophrenia in at risk siblings. Further, social cognitive deficits must be considered as important target for intervention among the at risk siblings to improve their outcome.

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 and grey matter abnormalities in individuals with ultra-high risk for psychosis

Neurological soft signs (NSSs), conventionally defined as subtle neurological abnormalities, are frequently found in individuals with schizophrenia. Many neuroimaging studies have also reported that NSSs are associated with grey matter changes in patients with schizophrenia at different stages of the illness. However, these findings may be confounded by the effect of antipsychotic medications, chronicity, and duration of untreated psychosis. Examining NSSs in individuals with ultra-high risk (UHR) for psychosis may help to identify the neuroanatomical substrates of NSSs related to the illness itself and to avoid these potential confounding effects. A sample of 21 individuals with UHR were included in the present study. NSSs were rated using the abridged version of the Cambridge Neurological Inventory. Grey matter volume was assessed using optimized voxel-based morphometry on images acquired by a high-resolution 3-T magnetic resonance imaging scanner. We found that higher NSS scores in individuals with UHR were associated with decreased grey matter volume at the superior and medial frontal cortex, the rectal cortex, the pre- and post-central cortex, the insula, the caudate, and the cerebellum. Our results suggest that these brain structural characteristics may represent the neuroanatomical substrate of NSSs in individuals with UHR. These findings contribute to the understanding of the intrinsic features of psychosis associated with NSSs and may provide insights into pre-schizophrenia pathophysiology.

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.

Association between neurological soft signs and antioxidant enzyme activity in schizophrenic patients

To determine the relationship between alterations in the activity of the enzymes participating in antioxidative defense system and neurological soft signs (NSS) in schizophrenic patients with the first episode psychosis (S_FE, n = 19), patients in relapse (S_R, n = 46), and healthy controls (HC, n = 20). NSS intensity and enzymatic plasma activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) were compared between S_FE, S_R and HC subjects and a follow-up correlation analyses between the enzyme activities and NSS intensity was performed. NSS intensity was increased four times in schizophrenic patients compared with healthy controls. Activities of SOD and CAT were 40% decreased in S_FE and these reductions were ameliorated by antipsychotic treatment. GPX activity was 20% decreased in both patient groups compared with controls. A negative correlation between NSS intensity and GPX activity was specifically found in the S_FE patients. The data in this report argue that a reduction of GPX activity might be one of the causes for the emergence of NSS at the onset of schizophrenia, and provide the evidence that antipsychotic therapy can attenuate activity reductions of SOD and CAT, but not the activity reduction of GPX and the intensity of NSS.

Motor dysfunction as an intermediate phenotype across schizophrenia and other psychotic disorders: Progress and perspectives

Primary motor abnormalities (PMA), as found in patients with schizophrenia, are quantitatively and qualitatively distinct markers of motor system abnormalities. PMA have been often referred to phenomena that are present across schizophrenia-spectrum disorders. A dysfunction of frontoparietal and subcortical networks has been proposed as core pathophysiological mechanism underlying the expression of PMA. However, it is unclear at present if such mechanisms are a common within schizophrenia and other psychotic disorders. To address this question, we review recent neuroimaging studies investigating the neural substrates of PMA in schizophrenia and so-called "nonschizophrenic nonaffective psychoses" (NSNAP) such as schizophreniform, schizoaffective, brief psychotic, and other unspecified psychotic disorders. Although the extant data in patients with schizophrenia suggests that further investigation is warranted, MRI findings in NSNAP are less persuasive. It is unclear so far which PMA, if any, are characteristic features of NSNAP or, possibly even specific for these disorders. Preliminary data suggest a relationship between relapsing-remitting PMA in hyper-/hypokinetic cycloid syndromes and neurodegenerative disorders of the basal ganglia, likely reflecting the transnosological relevance of subcortical abnormalities. Despite this evidence, neural substrates and mechanisms underlying PMA that are common in schizophrenia and NSNAP cannot be clearly delineated at this stage of research. PMA and their underlying brain circuits could be promising intermediate phenotype candidates for psychotic disorders, but future multimodal neuroimaging studies in schizophrenia and NSNAP patients and their unaffected first-degree relatives are needed to answer fundamental transnosologic questions.

Motor abnormalities and cognitive impairment in first-episode psychosis patients, their unaffected siblings and healthy controls

Motor abnormalities (MAs) may be already evidenced long before the beginning of illness and are highly prevalent in psychosis. However, the extent to which the whole range of MAs are related to cognitive impairment in psychosis remains understudied. This study aimed to examine comparatively the relationships between the whole range of motor abnormalities and cognitive impairments in the first-episode of psychosis (FEP), their unaffected siblings and healthy control subjects. Fifty FEP patients, 21 of their healthy siblings and 24 age- and sex matched healthy controls were included. Motor assessment included catatonic, extrapyramidal and neurological soft signs (NSS) by means of standardized instruments. An exhaustive neuropsychological battery was also performed to extract the 7 cognitive dimensions of MATRICS initiative. Higher scores on NSS but not on extrapyramidal and catatonic signs showed significant associations with worse cognitive performance in the three study groups. However, the pattern of associations regarding specific cognitive functions was different among the three groups. Moreover, extrapyramidal signs showed significant associations with cognitive impairment only in FEP patients but not in their unaffected siblings and healthy controls. Catatonic signs did not show any significant association with cognitive functioning in the three study groups. These findings add evidence to the associations between motor abnormalities, particularly NSS and extrapyramidal signs, and cognitive impairment in first-episode psychosis patients. In addition, our results suggest that the specific pattern of associations between MAs and cognitive functioning is different in FEP patients from those of the unaffected siblings and healthy subjects.

Prevalence and correlates of neurological soft signs in healthy controls without family history of any mental disorder: A neurodevelopmental variation rather than a specific risk factor?

OBJECTIVE

Neurological soft signs (NSS) are a group of minor non-localizable neurological abnormalities found more often in patients with schizophrenia and other mental disorders. The aim of the current study was to investigate their prevalence and correlates in healthy controls without family history of any mental disorder.

MATERIAL AND METHODS

The study sample included 122 normal subjects (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 subthreshold symptoms (MADRS, STAI) and functioning (GAF). Data on a number of socio-demographic variables were also gathered. The statistical analysis included the development of basic statistics tables and the calculation of Pearson correlation coefficients.

RESULTS

The results of the current study suggest that more than half of the study sample manifested at least one NSS and approximately 5% more than four. Still, the reported prevalence and NES scores are lower form those reported in the literature probably because of the carefully selected study sample. There were no significant correlations between NSS and any socio-demographic or clinical variable.

DISCUSSION

The current study is the first to study NSS in subjects without family history of any mental disorder and reports the presence of frequent silent neurodevelopmental events in the general population, probably in the form of a neurodevelopmental variation and possibly a weak generic rather than specific risk factor.

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, dissociation and alexithymia in patients with obsessive-compulsive disorder (OCD) and healthy subjects

A body of evidence has supported that patients with obsessive-compulsive disorder (OCD) have increased rates of various neurological soft signs (NSS) compared to controls. Various lines of research has documented robust relationships between OCD and dissociative symptomatology. The study aimed to examine the associations between obsessive-compulsive symptoms, dissociative experiences alexithymia, and NSS. The study included thirty OCD patients and thirty healthy controls, matched for age, marital status, education, and income. The Neurological Evaluation Scale (NES), Padua Inventory-Revised (PI-R), Dissociative Experiences Scale (DES) and Toronto Alexithymia Scale (TAS-20) were administered. In comparison to healthy controls, patients with OCD had difficulty sequencing for complex motor acts and greater absorption/ imaginative involvement. Using latent class analysis, the study sample was classified into two homogenous subsets as mild NSS (n = 45) and severe NSS (n = 15). Majority of the participants who were grouped into severe NSS latent class were OCD patient (n = 14, 93.3%). Furthermore, those with severe NSS reported greater levels of alexithymia and more severe obsessive-compulsive symptoms, particularly precision. We concluded that relationships between OCD severity and NSS appear to be of crucial importance. Our data along with accumulated evidence suggest that OCD associated with pronounced NSS may represent a specific subtype of the disorder.

Schizotypal traits and cognitive performance in siblings of patients with psychosis

INTRODUCTION

Schizotypy has been proposed to be the expression of genetic vulnerability to schizophrenia. The available literature shows cognitive similarities between schizotypy and schizophrenia, with mildly impaired performance being associated with schizotypy. This study aims to determine the relationship between schizotypy and cognitive performance in siblings of patients with psychosis.

METHODS

Schizotypal features and cognitive performance on a neuropsychological battery were compared between 48 siblings of patients with psychosis and 44 healthy controls. The relationships between schizotypy and cognitive performance were analysed by controlling the condition of being a sibling.

RESULTS

Siblings showed poorer performance on vigilance/sustained attention (M = 37.6; SD = 7.1) and selective attention/interference control/working memory (M = 23.28; SD = 2.7) tasks. The variance in vigilance/sustained attention performance was explained, at 30%, by the interpersonal factor of schizotypy on the suspiciousness dimension and the condition of being a sibling.

CONCLUSIONS

Interpersonal features of schizotypy in siblings of patients with psychosis are associated with deficits in vigilance/sustained attention performance.

Motor Abnormalities: From Neurodevelopmental to Neurodegenerative Through "Functional" (Neuro)Psychiatric Disorders

Background

Motor abnormalities (MAs) of severe mental disorders have been traditionally neglected both in clinical practice and research, although they are an increasing focus of attention because of their clinical and neurobiological relevance. For historical reasons, most of the literature on MAs has been focused to a great extent on schizophrenia, and as a consequence their prevalence and featural properties in other psychiatric or neuropsychiatric disorders are poorly known. In this article, we evaluated the extent to which catatonic, extrapyramidal and neurological soft signs, and their associated clinical features, are present transdiagnostically.

Methods

We examined motor-related features in neurodevelopmental (schizophrenia, obsessive compulsive disorder, autism spectrum disorders), "functional" (nonschizophrenic nonaffective psychoses, mood disorders) and neurodegenerative (Alzheimer's disease) disorders. Examination of the literature revealed that there have been very few comparisons of motor-related features across diagnoses and we had to rely mainly in disorder-specific studies to compare it transdiagnostically.

Results

One or more motor domains had a substantial prevalence in all the diagnoses examined. In "functional" disorders, MAs, and particularly catatonic signs, appear to be markers of episode severity; in chronic disorders, although with different degree of strength or evidence, all motor domains are indicators of both disorder severity and poor outcome; lastly, in Alzheimer's disease they are also indicators of disorder progression.

Conclusions

MAs appear to represent a true transdiagnostic domain putatively sharing neurobiological mechanisms of neurodevelopmental, functional or neurodegenerative origin.

Clinical Utility and Lifespan Profiling of Neurological Soft Signs in Schizophrenia Spectrum Disorders

Neurological soft signs (NSSs) bear the promise for early detection of schizophrenia spectrum disorders. Nonetheless, the sensitivity and specificity of NSSs in the psychosis continuum remains a topic of controversy. It is also unknown how NSSs reveal neurodevelopmental abnormality in schizophrenia. We investigated the effect sizes of NSSs in differentiating individuals with schizophrenia spectrum disorders from individuals with other psychiatric conditions and from covariate-matched healthy subjects. We also investigated the partitioned age-related variations of NSSs in both schizophrenia and healthy individuals. NSSs were assessed by the abridged version of the Cambridge Neurological Inventory (CNI) in 3105 participants, consisting of healthy individuals (n=1577), unaffected first-degree relatives of schizophrenia patients (n= 155), individuals with schizotypal personality disorder (n= 256), schizophrenia patients (n= 738), and other psychiatric patients (n= 379). Exact matching and propensity score matching procedures were performed to control for covariates. Multiple regression was used to partition age-related variations. Individuals along the schizophrenia continuum showed elevated levels of NSSs, with moderate effect sizes, in contrast to other psychiatric patients who had minimal NSSs, as well as matched healthy controls. Furthermore, the age-and-NSS relationship in schizophrenia patients was represented by a flat but overall elevated pattern, in contrast to a U-shaped pattern in healthy individuals. In sum, NSSs capture a moderate portion of psychosis proneness with reasonable specificity. Lifespan profiling reveals an abnormal developmental trajectory of NSSs in schizophrenia patients, which supports the endophenotype hypothesis of NSSs by associating it with the neurodevelopmental model of schizophrenia.

Research Review: Do motor deficits during development represent an endophenotype for schizophrenia? A meta-analysis

BACKGROUND

Early detection of schizophrenia risk is a critical goal in the field. Endophenotypes in children to relatives of affected individuals may contribute to this early detection. One of the lowest cost and longest theorized domains is motor development in children.

METHODS

A meta-analysis was conducted comparing individuals ≤21 years old with affected first-degree relatives (FDR) with (1) individuals from unaffected families (controls), or (2) individuals with FDR having other psychiatric disorders. Studies were classified by motor outcome and separate meta-analyses were performed across six correlated domains, with available N varying by domain.

RESULTS

Inclusion criteria were met by k = 23 independent studies with a total N = 18,582, and N across domains varying from 167 to 8619. The youth from affected families had delays in gross and fine motor development in infancy (k = 3, n = 167, Hedges'g = 0.644, confidence intervals (CI) = [0.328, 0.960], p < .001), walking milestones (k = 3, n = 608, g = 0.444, CI = [0.108, 0.780], p = .01), coordination (k = 8, n = 8619, g = 0.625, CI = [0.453, 0.797], p < .0001), and had more abnormal movements such as involuntary movements (k = 6, n = 8365, g = 0.291, CI = [0.041, 0.542], p = .02) compared with controls. However, not all effects survived correction for publication bias. Effects for neurological soft signs were small and not reliably different from zero (k = 4, n = 548, g = 0.238, CI = [-0.106, 0.583], p = .18). When comparing the FDR group to youth from families with other psychiatric disorders, the FDR group was distinguished by poorer gross and fine motor skills (k = 2, n = 275, g = 0.847, CI = [0.393, 1.300], p < .001).

CONCLUSIONS

Motor deficits during development likely represent an endophenotype for schizophrenia, although its specificity is limited in relation to other serious mental disorders. It holds promise as a low cost domain for early risk detection, although it will have to be combined with other indicators to achieve clinically usable prediction accuracy. Impaired coordination was the most robust result with a moderate effect size and lack of heterogeneity and publication bias.

Heritability and familiality of neurological soft signs: evidence from healthy twins, patients with schizophrenia and non-psychotic first-degree relatives

BACKGROUND

Neurological soft signs (NSS) have long been considered potential endophenotypes for schizophrenia. However, few studies have investigated the heritability and familiality of NSS. The present study examined the heritability and familiality of NSS in healthy twins and patient-relative pairs.

METHOD

The abridged version of the Cambridge Neurological Inventory was administered to 267 pairs of monozygotic twins, 124 pairs of dizygotic twins, and 75 pairs of patients with schizophrenia and their non-psychotic first-degree relatives.

RESULTS

NSS were found to have moderate but significant heritability in the healthy twin sample. Moreover, patients with schizophrenia correlated closely with their first-degree relatives on NSS.

CONCLUSIONS

Taken together, the findings provide evidence on the heritability and familiality of NSS in the Han Chinese population.

Motor dysfunction within the schizophrenia-spectrum: A dimensional step towards an underappreciated domain

At the beginning of the 20th century, genuine motor abnormalities (GMA) were considered to be intricately linked to schizophrenia. Subsequently, however, GMA have been increasingly regarded as unspecific transdiagnostic phenomena or related to side effects of antipsychotic treatment. Despite possible medication confounds, within the schizophrenia spectrum GMA have been categorized into three broad categories, i.e. neurological soft signs, abnormal involuntary movements and catatonia. Schizophrenia patients show a substantial overlap across a broad range of distinct motor signs and symptoms suggesting a prominent involvement of the motor system in disease pathophysiology. There have been several attempts to increase reliability and validity in diagnosing schizophrenia based on behavior and neurobiology, yet relatively little attention has been paid to the motor domain in the past. Nevertheless, accumulating neuroscientific evidence suggests the possibility of a motor endophenotype in schizophrenia, and that GMA could represent a specific dimension within the schizophrenia-spectrum. Here, we review current neuroimaging research on GMA in schizophrenia with an emphasis on distinct and common mechanisms of brain dysfunction. Based on a dimensional approach we show that multimodal neuroimaging combined with fine-grained clinical examination can result in a comprehensive characterization of structural and functional brain changes that are presumed to underlie core GMA in schizophrenia. We discuss the possibility of a distinct motor domain, together with its implications for future research. Investigating GMA by means of multimodal neuroimaging can essentially contribute at identifying novel and biologically reliable phenotypes in psychiatry.

Prefrontal cortex connectivity dysfunction in performing the Fist-Edge-Palm task in patients with first-episode schizophrenia and non-psychotic first-degree relatives

Neurological soft signs have been considered one of the promising neurological endophenotypes for schizophrenia. However, most previous studies have employed clinical rating data only. The present study aimed to examine the neurobiological basis of one of the typical motor coordination signs, the Fist–Edge–Palm (FEP) task, in patients with first-episode schizophrenia and their non-psychotic first degree relatives. Thirteen patients with first-episode schizophrenia, 14 non-psychotic first-degree relatives and 14 healthy controls were recruited. All of them were instructed to perform the FEP task in a 3 T GE Machine. Psychophysiological interaction (PPI) analysis was used to evaluate the functional connectivity between the sensorimotor cortex and frontal regions when participants performed the FEP task compared to simple motor tasks. In the contrast of palm-tapping (PT) vs. rest, activation of the left frontal–parietal region was lowest in the schizophrenia group, intermediate in the relative group and highest in the healthy control group. In the contrast of FEP vs. PT, patients with schizophrenia did not show areas of significant activation, while relatives and healthy controls showed significant activation of the left middle frontal gyrus. Moreover, with the increase in task complexity, significant functional connectivity was observed between the sensorimotor cortex and the right frontal gyrus in healthy controls but not in patients with first episode schizophrenia. These findings suggest that activity of the left frontal–parietal and frontal regions may be neurofunctional correlates of neurological soft signs, which in turn may be a potential endophenotype of schizophrenia. Moreover, the right frontal gyrus may play a specific role in the execution of the FEP task in schizophrenia spectrum disorders.

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Examine the neurobiological basis of the typical Fist–Edge–Palm (FEP) signs

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Patients with first-episode schizophrenia showed functional connectivity of the FEP signs.

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Right frontal gyrus plays a specific role in the FEP in patients and non-psychotic first-degree relatives.

Neurological soft signs in children with attention deficit hyperactivity disorder: Their relationship to executive function and parental neurological soft signs

The correlations between neurological soft signs (NSS) in children with attention deficit hyperactivity disorder (ADHD) and their executive function, symptoms of inattention, and hyperactivity-impulsivity and the NSS of their parents remain unclear. This study aimed to examine: (1) the prevalence of NSS in children with ADHD and their parents; (2) the correlation between the NSS of children with ADHD and the NSS of their parents; and (3) the correlation between the NSS of children with ADHD and their executive function and symptoms. NSS were assessed with the Cambridge Neurological Inventory (CNI) in 57 children with ADHD (and 80 parents) and 60 healthy children (and 75 parents). Executive function was measured with the Behavioral Rating Inventory of Executive Function (BRIEF). Children with ADHD and their parents had significantly higher NSS than normal children and their parents, respectively, and the NSS of children with ADHD were correlated more strongly with the NSS of their fathers than their mothers. No correlation was found between NSS and BRIEF executive function, but Disinhibition in children with ADHD was significantly correlated with hyperactivity-impulsivity symptoms. Paternal and maternal NSS provided different predictions for child NSS. It may be that NSS are more likely to be genetically transmitted by fathers.

Luria revisited: cognitive research in schizophrenia, past implications and future challenges

Contemporary psychiatry is becoming more biologically oriented in the attempt to elicit a biological rationale of mental diseases. Although mental disorders comprise mostly functional abnormalities, there is a substantial overlap between neurology and psychiatry in addressing cognitive disturbances. In schizophrenia, the presence of cognitive impairment prior to the onset of psychosis and early after its manifestation suggests that some neurocognitive abnormalities precede the onset of psychosis and may represent a trait marker. These cognitive alterations may arise from functional disconnectivity, as no significant brain damage has been found. In this review we aim to revise A.R. Luria's systematic approach used in the neuropsychological evaluation of cognitive functions, which was primarily applied in patients with neurological disorders and in the cognitive evaluation in schizophrenia and other related disorders. As proposed by Luria, cognitive processes, associated with higher cortical functions, may represent functional systems that are not localized in narrow, circumscribed areas of the brain, but occur among groups of concertedly working brain structures, each of which makes its own particular contribution to the organization of the functional system. Current developments in neuroscience provide evidence of functional connectivity in the brain. Therefore, Luria's approach may serve as a frame of reference for the analysis and interpretation of cognitive functions in general and their abnormalities in schizophrenia in particular. Having said that, modern technology, as well as experimental evidence, may help us to understand the brain better and lead us towards creating a new classification of cognitive functions. In schizophrenia research, multidisciplinary approaches must be utilized to address specific cognitive alterations. The relationships among the components of cognitive functions derived from the functional connectivity of the brain may provide an insight into cognitive machinery.

How much do we know about schizophrenia and how well do we know it? Evidence from the Schizophrenia Library

BACKGROUND

True findings about schizophrenia remain elusive; many findings are not replicated and conflicting results are common. Well-conducted systematic reviews have the ability to make robust, generalizable conclusions, with good meta-analyses potentially providing the closest estimate of the true effect size. In this paper, we undertake a systematic approach to synthesising the available evidence from well-conducted systematic reviews on schizophrenia.

METHOD

Reviews were identified by searching Medline, EMBASE, CINAHL, Current Contents and PsycINFO. The decision to include or exclude reviews, data extraction and quality assessments were conducted in duplicate. Evidence was graded as high quality if reviews contained large samples and robust results; and as moderate quality if reviews contained imprecision, inconsistency, smaller samples or study designs that may be prone to bias.

RESULTS

High- and moderate-quality evidence shows that numerous psychosocial and biomedical treatments are effective. Patients have relatively poor cognitive functioning, and subtle, but diverse, structural brain alterations, altered electrophysiological functioning and sleep patterns, minor physical anomalies, neurological soft signs, and sensory alterations. There are markers of infection, inflammation or altered immunological parameters; and there is increased mortality from a range of causes. Risk for schizophrenia is increased with cannabis use, pregnancy and birth complications, prenatal exposure to Toxoplasma gondii, childhood central nervous system viral infections, childhood adversities, urbanicity and immigration (first and second generation), particularly in certain ethnic groups. Developmental motor delays and lower intelligence quotient in childhood and adolescence are apparent.

CONCLUSIONS

We conclude that while our knowledge of schizophrenia is very substantial, our understanding of it remains limited.

Neurological soft signs and brainstem morphology in first-episode schizophrenia

BACKGROUND

Minor motor and sensory deficits or neurological soft signs (NSS) have frequently been reported in patients with schizophrenia at any stage of their illness. NSS have been demonstrated to correlate with neuroanatomical abnormalities in various brain regions. Despite its important role in the integration and coordination of automatic motor actions, the brainstem has so far rather been ignored in previous neuroimaging studies on NSS in schizophrenia.

METHOD

We investigated 21 right-handed first-episode schizophrenia patients using high-resolution magnetic resonance imaging at 3 T. The severity of NSS was measured with the Heidelberg Scale. Associations between NSS and both brainstem volume and shape changes were examined.

RESULTS

Higher NSS scores were significantly associated with structural alterations in the brainstem. According to volume measurements higher NSS scores correlated with global changes of the brainstem. Using shape analyses these associations referred to regionally specific morphometric alterations predominantly in the midbrain and pons.

CONCLUSION

The findings suggest that brainstem morphometric alterations are associated with the severity of NSS in patients with first-episode schizophrenia. They further indicate the involvement of the brainstem in the pathogenesis of schizophrenia.

An exploratory study of the relationship between neurological soft signs and theory of mind deficits in schizophrenia

Indirect evidence suggests partially common pathogenetic mechanisms for Neurological Soft Signs (NSS), neurocognition, and social cognition in schizophrenia. However, the possible association between NSS and mentalizing impairments has not yet been examined. In the present study, we assessed the ability to attribute mental states to others in patients with schizophrenia and predicted that the presence of theory of mind deficits would be significantly related to NSS. Participants were 90 clinically stable patients with a DSM-IV diagnosis of schizophrenia. NSS were assessed using the Neurological Evaluation Scale (NES). Theory of mind deficits were assessed using short verbal stories designed to measure false belief understanding. The findings of the study confirmed our hypothesis. Impaired sequencing of complex motor acts was the only neurological abnormality correlated with theory of mind deficits. By contrast, sensory integration, motor coordination and the NES Others subscale had no association with patients׳ ability to pass first- or second-order false belief tasks. If confirmed by future studies, the current findings provide the first preliminary evidence for the claim that specific NSS and theory of mind deficits may reflect overlapping neural substrates.

Neurological soft signs in obsessive-compulsive disorder: two empirical studies and meta-analysis

BACKGROUND

Neurological soft signs (NSS) have been inconsistently reported in obsessive-compulsive disorder (OCD) but may make an impact on treatment response. Method The current study examined the presence of NSS in two independent European samples of OCD patients (combined 85 patients and 88 matched healthy controls) using a standardized instrument and conducted a meta-analysis of all published studies identified in the literature with the aim to provide a more definitive answer to the question of whether OCD patients are characterized by increased NSS.

RESULTS

Both empirical studies found elevated NSS scores in patients compared with matched controls. The results of the meta-analysis, which included 15 studies (combined 498 patients and 520 controls) showed large effect sizes (Hedges' g=1.27, 95% confidence interval 0.80-1.75), indicating that OCD patients have significantly higher rates of NSS than matched controls on both sides of the body and in multiple domains (motor coordination, sensory integration and primitive reflexes). The results were robust and remained largely unchanged in our reliability analyses, which controlled for possible outliers. Meta-regression was employed to examine the role of potential variables of interest including sociodemographic variables, symptom severity, medication effects and the use of different instruments, but none of these variables was clearly associated with NSS.

CONCLUSIONS

As a group, OCD patients are characterized by increased rates of NSS, compared with healthy controls. However, their origins and potential clinical importance remain to be clarified. Future directions for research are discussed.

Neurological soft signs in non-psychotic patients with cannabis dependence

Psychomotor performance has consistently been found to be altered in chronic cannabis users. Neurological soft signs (NSS) reflect neurological dysfunction involving integrative networks, especially those involving the cerebellum, where cannabinoid receptors are particularly concentrated. Our objective was to study, for the first time, NSS in a group of patients with cannabis dependence compared with a of healthy control subjects, matched for age, gender and level of education. All outpatients seeking treatment for chronic cannabis use in the substance abuse department of Sainte-Anne Hospital in Paris between June 2007 and May 2009 and meeting the cannabis dependence DSM-IV criteria were included in the study (n = 45). Patients with psychotic disorders, bipolar 1 disorder and current alcohol, opioid or cocaine dependence were excluded. All patients and controls were assessed using the Diagnostic Interview for Genetic Studies, which screens for lifetime DSM-IV diagnoses, and the Standardized Neurological Examination of Neurological Soft Signs. NSS scores were significantly higher in patients with cannabis dependence compared with healthy subjects (8.90 ± 4.85 versus 6.71 ± 2.73, respectively, Mann-Whitney: U = 775.0, P = 0.05). Patients had particularly high scores on motor coordination and sensory integration NSS factors. Cannabis dependence is associated with more NSS and especially motor coordination and sensory integration signs. These results suggest that cannabinoids interact with the brain networks underlying NSS, known to be altered in schizophrenia.

Less cognitive and neurological deficits in schizophrenia patients carrying risk variant in ZNF804A

BACKGROUND

The rs1344706 single nucleotide polymorphism in the ZNF804A gene is a common variant with strong evidence for association with schizophrenia. Recent studies show an association of rs1344706 with cognitive functioning, and there is some evidence suggesting that the risk allele may increase susceptibility for a subtype of schizophrenia with relatively spared cognition.

METHODS

We tested the effect of rs1344706 genotype in 89 schizophrenia patients on 3 basic cognitive domains (working memory, processing speed and attention) shown to be severely impaired in schizophrenia. Also we investigated the effect of rs1344706 on the severity of neurological soft signs, subtle impairments in motor and sensory functions highly frequent in schizophrenia patients. Neurological soft signs and cognitive deficits are central features of schizophrenia and are tightly linked with clinical, social and functional outcome.

RESULTS

Our results show an association of higher rs1344706 risk allele load with improved performance on processing speed and with fewer neurological soft signs.

CONCLUSIONS

Together with other studies, our findings suggest that ZNF804A is associated with a subtype of schizophrenia with better cognitive and neurological functioning. Discovery of the specific pathways through which ZNF804A is exerting this effect may lead to better prevention, diagnosis and treatment for a specific group of schizophrenia patients.

A resting-state functional magnetic resonance imaging study on the first-degree relatives of persons with schizophrenia

In this study, resting state fMRI images and BOLD signals were recorded from 13 first-degree relatives of schizophrenic patients and 13 healthy controls. The data were analyzed with the ReHo approach after realignment, registration, and normalization in statistical parametric mapping 2 (SPM2). A two-sample t-test was used to analyze the ReHo differences between first-degree relatives and healthy controls in a voxel by voxel manner. A combined threshold of p < 0.005 and number of voxels >5 was designated as statistically significant. To evaluate cognitive deficits in first-degree relatives, attention/vigilance and verbal/visual memory were measured. Significant impairments in attention were observed in first-degree relatives compared to healthy controls. Significant abnormalities in ReHo were observed in resting brain in first-degree relatives. Decreased ReHo was found to be distributed over the bilateral middle frontal, middle temporal, cingulate gyrus and cerebellar tonsil; the left inferior frontal gyrus, inferior parietal lobule and dorsolateral prefrontal cortex; the right superior frontal gyrus and dorsolateral prefrontal cortex. Increased ReHo was found to be distributed in the right precuneus and superior temporal gyrus. These changes in ReHo suggest abnormality in the resting state brain function of first-degree relatives of schizophrenic patients and may be early signs for the development of schizophrenia.

Neurological soft signs in obsessive-compulsive disorder: the effect of co-morbid psychosis and evidence for familiality

Patients with obsessive-compulsive disorder (OCD) have increased rates of neurological soft signs (NSS) when compared to healthy controls. However, previous findings have been confounded by the presence of co-morbidity with disorders themselves associated with increased NSS, such as schizophrenia. Moreover, it remains unclear whether NSS in OCD reflect a vulnerability to this disorder. This study aimed to examine: 1) the severity of NSS in patients with OCD alone, in patients with OCD and co-morbid psychosis (schizophrenia or bipolar disorders), and in healthy controls; and b) whether unaffected first-degree relatives of patients with OCD also demonstrate a higher prevalence rate of NSS than healthy controls. NSS were assessed with the Cambridge Neurological Inventory (CNI) in 100 patients with OCD, 38 patients with OCD and psychosis (22 with bipolar disorders and 16 with schizophrenia), and 101 healthy controls. Forty-seven unaffected first-degree relatives of patients with OCD only were also administered the CNI. Patients with OCD showed significantly higher scores in motor coordination and total NSS than controls, and patients with OCD co-morbid with psychosis also showed significantly higher scores in motor coordination and total NSS than controls. Although there were no differences in NSS between patients with OCD only and OCD and psychosis as a whole, patients with OCD co-morbid with schizophrenia showed significantly higher scores in motor coordination than patients with OCD, patients with OCD and bipolar disorder, and healthy controls. Unaffected first-degree relatives only showed a higher prevalence rate than healthy controls in specific motor coordination signs, such as Opposition and Extinction. These findings suggest that patients with OCD exhibit more NSS than healthy controls, and that motor coordination signs may be even more extensive when OCD is co-morbid with psychosis. Some of these abnormalities may be indicative of a vulnerability to these disorders, as indicated by their presence in un-affected first-degree relatives.

Treatment response of neurological soft signs in drug-naïve patients with a first psychotic episode

BACKGROUND

Neurological soft signs (NSS) are intrinsic features of psychosis that appear years before beginning a drug treatment. However, whether NSS respond to antipsychotics and whether these changes are clinically reliable and significant remains to be seen.

OBJECTIVE

We sought to determine the effect of antipsychotics on NSS in a first-episode psychosis (FEP) sample who had never exposed to antipsychotics.

METHODS

We included 100 antipsychotic-naïve patients with FEP in this study. 77 patients completed the study assessments at baseline, 1 month and 6 months. The Neurological Evaluation Scale (NES) evaluated NSS. Patients were alternatively selected to receive risperidone or olanzapine treatments and continued participation in their mental health setting during follow-up with one of four treatment groups: risperidone, olanzapine, mixed antipsychotics or no medication. We also included a control group of 28 healthy volunteers.

RESULTS

Treatment groups showed a statistically significant improvement on total NES scores and most NES subscales except for 'frontal signs', regardless of antipsychotic allocation. NSS changes were reliable; however, there was great variation in the total NES scores between treatment groups, ranging from 4% to 24%. Clinically meaningful changes (CMCs) on total NES scores ranged from 25% to 50%. Six patients (7.8%) demonstrated a reliable change (RC) and CMC on total NES scores.

CONCLUSIONS

NSS improved significantly over follow up regardless of the treatment regimen assigned to antipsychotic-naïve patients with a FEP. However, only 6 (7.8%) achieved a reliable and clinically meaningful improvement. The pattern of response of NSS to antipsychotic drugs evidenced both state and trait characteristics.