Soft signs and neuropsychological performance in schizophrenia

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.

Relationship between neurological and cerebellar soft signs, and implicit motor learning in schizophrenia and bipolar disorder

BACKGROUND

Schizophrenia (SZ) and bipolar disorder (BD) patients share deficits in motor functions in the form of neurological (NSS) and cerebellar soft signs (CSS), and implicit motor learning disturbances. Here, we use cluster analysis method to assess (1) the relationship between those abnormalities in SZ and BD and (2) the differences between those groups.

METHODS

33 SZ patients, 33 BD patients as well as 31 healthy controls (HC) took part in the study. We assessed CSS with the International Cooperative Ataxia Rating Scale (ICARS) and NSS with the Neurological Evaluation Scale (NES). Implicit motor learning was evaluated with the Serial Reaction Time Task (SRTT). Participants were divided into clusters (Ward's method) based on the mean response time and mean error rate in SRTT. The difference in ICARS and NES scores, and SRTT variables between clusters were evaluated. We have measured associations between SRTT parameters and both ICARS and NES total scores and subscores.

RESULTS

Cluster analysis based on the SRTT parameters allowed to extract three clusters. Those were characterized by the increasing disruption of motor functioning (psychomotor retardation, the severity of NSS and CSS) regardless of the diagnosis. Cluster 1 covered almost all of HC and was characterized by faster reaction times and small number of errors. BD and SZ patients represented in cluster 1, although fully functional in performing the SRTT, showed higher rates of NSS and CSS. Patients with BD and SZ were set apart in clusters 2 and 3 in a similar proportion. Cluster 2 presented significantly slower reaction times but with the comparable number of errors to cluster 1. Cluster 3 consisted of participants with normal or decreased reaction time and significantly increased number of errors. None of the clusters were predominantly composed of the patients representing one psychiatric diagnosis.

CONCLUSIONS

To our best knowledge, we are presenting the first data indicating the relationship between implicit motor learning and NSS and CSS in SZ and BD patients' groups. Lack of clusters predominantly represented by patients with the diagnosis of SZ or BD may refer to the model of schizophrenia-bipolar disorder boundary, pointing out the similarities between those two disorders.

Cross-sectional study comparing cognitive function in treatment responsive versus treatment non-responsive schizophrenia: evidence from the STRATA study

BACKGROUND

70%-84% of individuals with antipsychotic treatment resistance show non-response from the first episode. Emerging cross-sectional evidence comparing cognitive profiles in treatment resistant schizophrenia to treatment-responsive schizophrenia has indicated that verbal memory and language functions may be more impaired in treatment resistance. We sought to confirm this finding by comparing cognitive performance between antipsychotic non-responders (NR) and responders (R) using a brief cognitive battery for schizophrenia, with a primary focus on verbal tasks compared against other measures of cognition.

DESIGN

Cross-sectional.

SETTING

This cross-sectional study recruited antipsychotic treatment R and antipsychotic NR across four UK sites. Cognitive performance was assessed using the Brief Assessment of Cognition in Schizophrenia (BACS).

PARTICIPANTS

One hundred and six participants aged 18-65 years with a diagnosis of schizophrenia or schizophreniform disorder were recruited according to their treatment response, with 52 NR and 54 R cases.

OUTCOMES

Composite and subscale scores of cognitive performance on the BACS. Group (R vs NR) differences in cognitive scores were investigated using univariable and multivariable linear regressions adjusted for age, gender and illness duration.

RESULTS

Univariable regression models observed no significant differences between R and NR groups on any measure of the BACS, including verbal memory (ß=-1.99, 95% CI -6.63 to 2.66, p=0.398) and verbal fluency (ß=1.23, 95% CI -2.46 to 4.91, p=0.510). This pattern of findings was consistent in multivariable models.

CONCLUSIONS

The lack of group difference in cognition in our sample is likely due to a lack of clinical distinction between our groups. Future investigations should aim to use machine learning methods using longitudinal first episode samples to identify responder subtypes within schizophrenia, and how cognitive factors may interact within this.

TRAIL REGISTRATION NUMBER

REC: 15/LO/0038.

Neurological Soft Signs (NSS) in Census-Based, Decade-Adjusted Healthy Adults, 20 to >70 Years of Age

Neurological soft signs (NSS) represent minor neurological features and have been widely studied in psychiatric disease. The assessment is easily performed. Quantity and quality may provide useful information concerning the disease course. Mostly, NSS scores differ significantly between patients and controls. However, literature does not give reference values. In this pilot study, we recruited 120 healthy women and men to build a cross-sectional, census-based sample of healthy individuals, aged 20 to >70 years, subdivided in 10-year blocks for a close approach to the human lifeline. Testing for NSS and neurocognitive functioning was performed following the exclusion of mental and severe physical illness. NSS scores increased significantly between ages 50+ and 60+, which was primarily accountable to motor signs. Gender and cognitive functioning were not related to changes of scores. Although the number of individuals is small, study results may lay a foundation for further validation of NSS in healthy individuals.

Effects of different types of sensory signals on reaching performance in persons with chronic schizophrenia

Previous studies have reported movement abnormalities in persons with schizophrenia. This study aimed to examine the differences between persons with chronic schizophrenia and healthy control participants in reaching movement and the effects of sensory signals on reaching performance in persons with chronic schizophrenia. A counter-balanced repeated-measures design was employed. Twenty persons with schizophrenia and 20 age- and gender-matched control participants were recruited in this study. Reaching performance was measured in three types of sensory signal conditions (visual, auditory, and no signal), i.e., two externally triggered and one self-initiated movement were assessed in reaction time/inter-response interval, movement time, peak velocity, percentage of time in which peak velocity occurred, and movement units. The results revealed significant main effects of group in reaction time/inter-response interval (p = 0.003), movement time (p < 0.001), peak velocity (p < 0.001), and movement units (p < 0.001). The persons with chronic schizophrenia demonstrated slower response to signals and in self-initiated movement, increased movement time, and less forceful and less smooth movement compared to healthy control participants when performing the reaching task. The interaction effect between group and signal in reaction time/inter-response interval was also significant (p < 0.001). The inter-response interval for self-initiated reaching was the shortest in healthy controls. Conversely, the inter-response interval for self-initiated reaching was the longest in persons with schizophrenia. The main effect of the signal on movement time was significant (p < 0.001). The movement time of reaching was longer in response to the auditory signal than in response to visual or self-initiated. The differences in percentages of time in which peak velocity occurred between persons with schizophrenia and healthy controls (p > 0.01) and across the three conditions (p > 0.01) were non-significant. Neither duration of illness nor antipsychotic dosage was significantly associated with reaching performance (all p > 0.01). In conclusion, these findings indicate that reaching movement in persons with chronic schizophrenia is slower, less forceful, and less coordinated compared to healthy control participants. In addition, persons with chronic schizophrenia also had shorter inter-response interval for self-initiated movement and shorter movement time in auditory signal condition, independent of duration of illness and antipsychotic dosage.

Neurological soft signs (NSS) and cognitive impairment in chronic schizophrenia

Recent studies indicate that neurological soft signs (NSS) in schizophrenia are associated with generalized cognitive impairments rather than changes in specific neuropsychological domains. However, the majority of studies solely included first-episode patients or patients with a remitting course and did not consider age, course, education or severity of global cognitive deficits as potential confounding variables. Therefore, we examined NSS with respect to cognitive deficits in chronic schizophrenia, i.e. patients who are particularly vulnerable to both, NSS and cognitive impairments.

Eighty patients with chronic schizophrenia (43.36 ± 15a) and 60 healthy controls (47.52 ± 14.8a) matched for age, sex and years of education were examined on the Heidelberg NSS scale and a broad neuropsychological battery including short term, working, logical and autobiographic memory (AM), theory of mind (ToM), psychomotor speed and cognitive flexibility.

When contrasted with the controls, patients showed significantly higher NSS scores and impairments in all neuropsychological domains but short-term memory. NSS were significantly associated with all neuropsychological domains considered but short-term memory and semantic AM. Except for episodic AM (which was significantly correlated with NSS in patients only) these correlations applied to both groups and were confirmed when age, years of education and severity of global cognitive deficits (Mini Mental State Examination) were controlled for.

Results demonstrate that NSS reflect a rather wide range of cognitive impairments in schizophrenia, which also involves episodic AM and ToM. These associations were not accounted for by age, education or severity of global cognitive deficits and facilitate the clinical usage of NSS as a screening instrument.

Manual dexterity and brain structure in patients with schizophrenia: A whole-brain magnetic resonance imaging study

The Purdue Pegboard Test (PPT) is a motor coordination task used to assess manual dexterity. Although several brain regions are thought to be involved in PPT performance, the relationship of the task with decreased insular volume has not been investigated. The PPT was administered to 83 subjects diagnosed with schizophrenia (mean ± standard deviation age: 38.6 ± 11.2 years; 47 males, 36 females) and 130 healthy controls (42.1 ± 15.2 years; 67 males, 63 females). All subjects were Japanese and right-handed. Gray matter volume was analyzed using voxel-based morphometry in statistical parametric mapping, while white matter measures were analyzed using diffusion tensor imaging in tract-based spatial statistics. For the patients with schizophrenia, the left-hand scores positively correlated with the right insular and bilateral operculum volumes, while the summation score (sum of left-, right-, and both-hands scores) positively correlated with the right insular volume, and the summation and assembly (number of assemblies completed) scores correlated with the diffuse white matter fractional anisotropy, axial diffusivity, and radial diffusivity values. In contrast, no significant correlations were found for the controls. These results suggested that decreased insular volume and white matter measures contributed to the impairments in manual dexterity observed in subjects with schizophrenia.

Assessment of neurological soft signs in pediatric patients with HIV infection

BACKGROUND

Children and adolescents comprise a significant proportion of people living with HIV. The effects of HIV on the growing brain have generated interest among researchers in this field. Deficits arising during this crucial phase of neuromaturation due to HIV infection need to be assessed and addressed. Neurological soft signs (NSSs) can act as a proxy marker for underlying neuropsychological deficits. The present study aims to study the NSSs in pediatric patients with HIV and compare with healthy controls (HCs).

MATERIALS AND METHODS

Forty-eight children aged between 6 and 16 years diagnosed with HIV were selected by purposive sampling, and the Physical and Neurological Examination of Soft Signs (PANESS) scale was applied. Fifty children matched by age and sex were recruited from a nearby school, and the PANESS scale was applied. Children were divided into age- and gender-specific groups. The outcome scores of cases and controls groups were compared.

RESULTS

Males and females aged 13-16 years with HIV showed more soft signs as compared to HCs, with respect to gait errors, dysrhythmia, impersistence, speed of repetitive and sequenced movements, overflow with gaits, overflow with sequenced movements, total overflow, and overflow in excess of age. The differences in scores were less marked in younger age groups among both the genders.

CONCLUSIONS

The persistence of NSSs in older age group in HIV-infected children may point toward the presence of HIV-associated neurological disorder.

Neurological soft signs and cognitive functions: Amongst euthymic bipolar I disorder cases, non-affected first degree relatives and healthy controls

Both neurological soft signs (NSS) and cognitive deficits are present among euthymic bipolar patients. NSS could be related to neurocognitive performance, but this is not explored thoroughly. Healthy relatives of patients may also suffer from similar deficits. This study compared NSS and cognitive functions in euthymic Bipolar I Disorder (BPI) cases to their non-affected first degree relatives and healthy controls. We also investigated the association between NSS and cognitive functions in these three groups. NSS were assessed in three groups using Neurological Evaluation Scale-revised (NES-r). Eight cognitive domains were assessed in 31 euthymic BPI cases, their 30 non-affected first degree relatives and 30 healthy controls using Computerized Neurocognitive Battery (CNB). Euthymic BPI patients had significantly more NSS than non-affected first degree relatives on 5/7 tests (p-value ranges from 0.042 to p=0.0001) and healthy controls on all tests (p-value from 0.042 to <0.0001). Non-affected first degree relatives and controls did not have any significant difference. BPI participants performed worse than their non-affected first degree relatives on one neurocognitive domain of CNB (spatial memory accuracy, p=0.03) and healthy controls on four domains (spatial memory accuracy (p=0.04), abstraction and mental flexibility efficiency (p=0.04), spatial memory efficiency (p=0.04), and emotion efficiency (p=0.04). Non-affected relatives and healthy controls were similar on neurocognitive domains. Accuracy and efficiency indices of some specific cognitive domains were negatively associated with AV rating and tap copying NSS ratings.

A clinical study of neurological soft signs in patients with schizophrenia

BACKGROUND AND AIM

Neurological soft signs (NSSs) are "objectively measured, nonlocalizing abnormalities, not related to impairment of a specific brain region, reflecting improper cortical-subcortical and intercortical connections." The possibility of NSS as an endophenotype in schizophrenia has been studied across the globe. We aimed at finding the prevalence of NSS among patients with schizophrenia as well as the associations of NSS between various sociodemographic and illness variables.

SUBJECTS AND METHODS

One hundred patients between the age group of 16 and 60 years were serially selected from the inpatient department of a tertiary care hospital who have been diagnosed as a case of schizophrenia according to the International Classification of Diseases version 10 during 1 year period. A semi-structured pro forma was used to collect various demographic as well as illness data, and subjects were clinically evaluated for NSS using neurological evaluation scale.

RESULTS

The prevalence of NSSs was found to be 67%, significant association was found between NSS and age, occupation, and duration of illness. A statistically significant correlation was found between NSS and age, NSS and duration of illness.

CONCLUSION

The validity of NSS as an endophenotype lies in the fact that it should be independent of all sociodemographic and illness variables. However, our study evaluated some statistically significant findings between them. Hence, further researches are required with properly adjusted controls to find if the associations obtained between NSS and different variables here are true or whether there are some confounding factors included.

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.

Re-visiting the nature and relationships between neurological signs and neurocognitive functions in first-episode schizophrenia: An invariance model across time

The present study examined different types of neurological signs in patients with first-episode schizophrenia and their relationships with neurocognitive functions. Both cross-sectional and longitudinal designs were adopted with the use of the abridged Cambridge Neurological Inventory which comprises items capturing motor coordination, sensory integration and disinhibition. A total of 157 patients with first-episode schizophrenia were assessed at baseline and 101 of them were re-assessed at six-month interval. A structural equation model (SEM) with invariance model across time was used for data analysis. The model fitted well with the data at baseline assessment, X^2(21) = 21.78, p = 0.413, NFI = 0.95, NNFI = 1.00, CFI = 1.00, IFI = 1.00, RMSEA = 0.015. Subsequent SEM analysis with invariance model at six-month interval also demonstrated the same stable pattern across time and showed strong measurement invariance and structure invariance across time. Our findings suggest that neurological signs capture more or less the same construct captured by conventional neurocognitive tests in patients with schizophrenia. The measurement and structure of these relationships appear to be stable over time.

Extrapyramidal symptoms and cognitive test performance in patients with schizophrenia

BACKGROUND

Movement disorders are common in individuals with schizophrenia, even in those who are not exposed to antipsychotic medications. Extrapyramidal symptoms (EPS) are among the most common abnormal movements in schizophrenia, but their relationship with other features of the illness such as cognition is not well characterized.

METHODS

Three hundred and twenty-five individuals with schizophrenia who were not receiving any antipsychotic or anticholinergic medication and participated in the baseline visit of the Clinical Antipsychotic Treatment of Intervention Effectiveness study were included in the present study. EPSs were assessed using the Simpson-Angus Scale, while cognition was measured with a comprehensive neuropsychological test battery. The relationship between EPS and cognitive test performance was evaluated both dimensionally and categorically.

RESULTS

Greater severity of EPS was significantly associated with worse cognitive test performance evaluated using a composite score. Eighty-six patients were identified as having parkinsonism and these patients performed worse on cognitive tests than non-parkinsonian patients. These findings remained significant even after accounting for other variables such as severity of psychopathology, sedation, akathisia and dyskinesia.

CONCLUSIONS

The present results demonstrate that severity of EPS is reliably linked with poorer scores on tests of cognition. While this may reflect a common pathophysiology underlying neuromotor and neurocognitive deficits, it may also be the case that parkinsonian symptoms such as rigidity and bradykinesia impede test taking ability. Regardless of mechanism, inferences regarding cognitive impairment should take into account the presence of EPS, as well as other variables that may mediate cognitive test findings.

Correlation of neurological soft signs and neurocognitive performance in first episode psychosis

Neurological soft signs and neurocognitive impairments are commonly observed in first episode psychosis but the correlation of these factors remains controversial. Here, we evaluated 30 patients with remitted first episode psychosis and 30 healthy controls for the presence and severity of neurological soft signs (using the Neurological Evaluation Scale--NES) and for neurocognitive impairments (using seven subtests of the Cambridge Neuropsychological Test Automated Battery--CANTAB). NES score was higher in patients compared to controls. Neurocognitive impairment was evident in patients in the following domains: working memory, spatial recognition memory, attention set shifting, planning and inhibition. The NES revealed significant correlations with spatial working memory performance and Intra-Extra Dimensional Set Shifting (as a component of executive function). These correlations were observed both in patients and in controls. Planning and inhibition showed correlation with the total NES score and the sequencing of complex motor acts in both groups. In addition, spatial span and spatial recognition memory showed significant correlation with total NES score and the sequencing of complex motor acts in controls. The correlation between sequencing of complex motor acts and specific domains of neurocognitive tasks suggests that similar neuroanatomical substrates might be implicated in these processes.

The therapeutic potential of the cerebellum in schizophrenia

The cognitive role of the cerebellum is critically tied to its distributed connections throughout the brain. Accumulating evidence from anatomical, structural and functional imaging, and lesion studies advocate a cognitive network involving indirect connections between the cerebellum and non-motor areas in the prefrontal cortex. Cerebellar stimulation dynamically influences activity in several regions of the frontal cortex and effectively improves cognition in schizophrenia. In this manuscript, we summarize current literature on the cingulocerebellar circuit and we introduce a method to interrogate this circuit combining opotogenetics, neuropharmacology, and electrophysiology in awake-behaving animals while minimizing incidental stimulation of neighboring cerebellar nuclei. We propose the novel hypothesis that optogenetic cerebellar stimulation can restore aberrant frontal activity and rescue impaired cognition in schizophrenia. We focus on how a known cognitive region in the frontal cortex, the anterior cingulate, is influenced by the cerebellum. This circuit is of particular interest because it has been confirmed using tracing studies, neuroimaging reveals its role in cognitive tasks, it is conserved from rodents to humans, and diseases such as schizophrenia and autism appear in its aberrancy. Novel tract tracing results presented here provide support for how these two areas communicate. The primary pathway involves a disynaptic connection between the cerebellar dentate nuclei (DN) and the anterior cingulate cortex. Secondarily, the pathway from cerebellar fastigial nuclei (FN) to the ventral tegmental area, which supplies dopamine to the prefrontal cortex, may play a role as schizophrenia characteristically involves dopamine deficiencies. We hope that the hypothesis described here will inspire new therapeutic strategies targeting currently untreatable cognitive impairments in schizophrenia.

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.

Finger Tapping: Why Can't We Alternate Hands?

The purpose of this research was to determine if there is any need, as per the Halstead-Reitan instructions, to test each hand uninterruptedly on the Finger Oscillation Test (FoT). To the authors' knowledge, there is no widely available research addressing this issue. Enabling administration of the FoT using alternate hands would theoretically make the administration of the assessment more efficient. In this study, participants consisted of 49 graduate students. All were administered the FoT with standard instructions and using an alternating-hands method. The order of administration was counterbalanced to avoid practice effects, and subjects completed distractor tasks between administrations. Results indicated there was a difference between the two administration methods for both dominant, t(47) = -4.09, p < .001, and nondominant, t(48) = -4.17, p < .001, hands. Surprisingly, mean T-scores were significantly higher for both the dominant and nondominant hands in the alternative administration group when compared with the standard method score (50 vs. 44 and 51 vs. 44, respectively). The standard deviations for both hands were also lower using the alternative method. This study highlights the need for neuropsychologists to be aware of the established administration protocols for tests and to carefully consider how deviations from these methods could affect test scores.

Obstetric complications and neurological soft signs in male patients with schizophrenia

Bersani G, Clemente R, Gherardelli S, Bersani FS, Manuali G. Obstetric complications and neurological soft signs in male patients with schizophrenia.

Objective: The study investigated the relationship between neurological soft signs (NSS) and obstetric complications (OCs) in patients with schizophrenia.

Methods: Sixty-three male patients with schizophrenia were divided into two subgroups, based on the OCs presence or absence, which were compared in relation to NSS prevalence. After that, a Person's correlation test was performed to explore the correlation between NSS and OCs severity.

Results: The subgroup with OCs showed more NSS, but there were not significant correlations between NSS and OCs severity.

Conclusions: It seems that any OC, without distinction in typology and severity, could unspecifically impair the neurodevelopment and inducing NSS expression. Our findings confirm the hypothesis that neurodevelopment alterations, such as those probably induced by OCs, can contribute to a premorbid brain dysfunctional state expressed by NSS.

An examination of relationship between neurological soft signs and neurocognition

OBJECTIVE

Neurological soft signs (NSS) and cognitive function had been examined in schizophrenia, but their relationship has remained elusive for several years. We examined the relationship between NSS and cognitive functions in the present study.

METHOD

A cross sectional study was carried out. Subjects were drawn from first degree relatives of schizophrenia patients, admitted as inpatient or attending as an outpatient. Controls were recruited by word of mouth from hospital staff and visitors of hospitalized patients. Those subjects who satisfied the screening process were subjected to Cambridge Neurological Inventory for soft sign assessment and digit span test, paired associate learning test (PALT) and visuo-spatial working memory matrix (VSWMM) for cognitive function assessment. Correlation analysis and structural equation modeling (SEM) was used for analysis.

RESULT

Significant negative correlation of primitive reflexes with PALT; of motor coordination with VSWMM, working memory (WM) and cognitive index; of total NSS with WM and cognitive index among first degree relatives. SEM showed that motor soft signs have important negative influence over WM.

CONCLUSION

The current findings indicate that NSS have significant negative effect on cognitive functioning.

Neurological soft signs in schizophrenia - The past, the present and the future

Clinical neurological abnormalities in patients with schizophrenia have been generally called "Neurological Soft Signs" (NSS). Studies have consistently shown increased NSS in patients with schizophrenia as compared to healthy persons. Early studies were limited by possible confounds of prior neuroleptic medications and illness chronicity. Studies in first episode never treated schizophrenia patients have addressed these confounds. The clinical significance of these findings and the correlation with cognitive dysmetria is the focus of the current review. Relevant literature was obtained using PUBMED and MEDLINE search (1980-2008) and a direct search of reference list of pertinent journal articles. In a 2003 study, neuroleptic-naive schizophrenia patients had significantly more NSS than controls. Patients who were more neurologically impaired had more negative symptoms. Higher NSS scores in treatment-naive schizophrenia patients and the absence of correlation between NSS and illness duration lends support to a neurodevelopmental pathogenesis for schizophrenia. The finding of incoordination and cerebellar signs in most studies also supports the "cognitive dysmetria" explanatory model for schizophrenia. A significant subgroup of patients with schizophrenia may have more neuropathological abnormalities, which predisposes them for a more severe and chronic course of illness. These patients may potentially be identified by clinical neurological examination, which might be very important for prognostication and evolving better methods of treatment for these patients. NSS, by themselves or as a composite index with other neurobiological parameters, hold potential as a candidate endophenotype for schizophrenia.

Neurological abnormalities and neurocognitive functions in healthy elder people: a structural equation modeling analysis

BACKGROUND/AIMS

Neurological abnormalities have been reported in normal aging population. However, most of them were limited to extrapyramidal signs and soft signs such as motor coordination and sensory integration have received much less attention. Very little is known about the relationship between neurological soft signs and neurocognitive function in healthy elder people. The current study aimed to examine the underlying relationships between neurological soft signs and neurocognition in a group of healthy elderly.

METHODS

One hundred and eighty healthy elderly participated in the current study. Neurological soft signs were evaluated with the subscales of Cambridge Neurological Inventory. A set of neurocognitive tests was also administered to all the participants. Structural equation modeling was adopted to examine the underlying relationship between neurological soft signs and neurocognition.

RESULTS

No significant differences were found between the male and female elder people in neurocognitive function performances and neurological soft signs. The model fitted well in the elderly and indicated the moderate associations between neurological soft signs and neurocognition, specifically verbal memory, visual memory and working memory.

CONCLUSIONS

The neurological soft signs are more or less statistically equivalent to capture the similar information done by conventional neurocognitive function tests in the elderly. The implication of these findings may serve as a potential neurological marker for the early detection of pathological aging diseases or related mental status such as mild cognitive impairment and Alzheimer's disease.

Neurexin-1 and frontal lobe white matter: an overlapping intermediate phenotype for schizophrenia and autism spectrum disorders

Background

Structural variation in the neurexin-1 (NRXN1) gene increases risk for both autism spectrum disorders (ASD) and schizophrenia. However, the manner in which NRXN1 gene variation may be related to brain morphology to confer risk for ASD or schizophrenia is unknown.

Method/Principal Findings

53 healthy individuals between 18–59 years of age were genotyped at 11 single nucleotide polymorphisms of the NRXN1 gene. All subjects received structural MRI scans, which were processed to determine cortical gray and white matter lobar volumes, and volumes of striatal and thalamic structures. Each subject's sensorimotor function was also assessed. The general linear model was used to calculate the influence of genetic variation on neural and cognitive phenotypes. Finally, in silico analysis was conducted to assess potential functional relevance of any polymorphisms associated with brain measures. A polymorphism located in the 3′ untranslated region of NRXN1 significantly influenced white matter volumes in whole brain and frontal lobes after correcting for total brain volume, age and multiple comparisons. Follow-up in silico analysis revealed that this SNP is a putative microRNA binding site that may be of functional significance in regulating NRXN1 expression. This variant also influenced sensorimotor performance, a neurocognitive function impaired in both ASD and schizophrenia.

Conclusions

Our findings demonstrate that the NRXN1 gene, a vulnerability gene for SCZ and ASD, influences brain structure and cognitive function susceptible in both disorders. In conjunction with our in silico results, our findings provide evidence for a neural and cognitive susceptibility mechanism by which the NRXN1 gene confers risk for both schizophrenia and ASD.

Neurological soft signs in schizophrenia: a meta-analysis

BACKGROUND

Neurological soft signs (NSS) are hypothesized as candidate endophenotypes for schizophrenia, but their prevalence and relations with clinical and demographic data are unknown. The authors undertook a quantification (meta-analysis) of the published literature on NSS in patients with schizophrenia and healthy controls. A systematic search was conducted for published articles reporting NSS and related data using standard measures in schizophrenia and healthy comparison groups.

METHOD

A systematic search was conducted for published articles reporting data on the prevalence of NSS in schizophrenia using standard clinical rating scales and healthy comparison groups. Meta-analyses were performed using the Comprehensive Meta-analysis software package. Effect sizes (Cohen d) indexing the difference between schizophrenic patients and the healthy controls were calculated on the basis of reported statistics. Potential moderator variables evaluated included age of patient samples, level of education, sample sex proportions, medication doses, and negative and positive symptoms.

RESULTS

A total of 33 articles met inclusion criteria for the meta-analysis. A large and reliable group difference (Cohen d) indicated that, on average, a majority of patients (73%) perform outside the range of healthy subjects on aggregate NSS measures. Cognitive performance and positive and negative symptoms share 2%-10% of their variance with NSS.

CONCLUSIONS

NSS occur in a majority of the schizophrenia patient population and are largely distinct from symptomatic and cognitive features of the illness.

Genetics and intermediate phenotypes of the schizophrenia--bipolar disorder boundary

Categorization of psychotic illnesses into schizophrenic and affective psychoses remains an ongoing controversy. Although Kraepelinian subtyping of psychosis was historically beneficial, modern genetic and neurophysiological studies do not support dichotomous conceptualization of psychosis. Evidence suggests that schizophrenia and bipolar disorder rather present a clinical continuum with partially overlapping symptom dimensions, neurophysiology, genetics and treatment responses. Recent large scale genetic studies have produced inconsistent findings and exposed an urgent need for re-thinking phenomenology-based approach in psychiatric research. Epidemiological, linkage and molecular genetic studies, as well as studies in intermediate phenotypes (neurocognitive, neurophysiological and anatomical imaging) in schizophrenia and bipolar disorders are reviewed in order to support a dimensional conceptualization of psychosis. Overlapping and unique genetic and intermediate phenotypic signatures of the two psychoses are comprehensively recapitulated. Alternative strategies which may be implicated into genetic research are discussed.

Neurological soft signs and their relationships to neurocognitive functions: a re-visit with the structural equation modeling design

Background

Neurological soft signs and neurocognitive impairments have long been considered important features of schizophrenia. Previous correlational studies have suggested that there is a significant relationship between neurological soft signs and neurocognitive functions. The purpose of the current study was to examine the underlying relationships between these two distinct constructs with structural equation modeling (SEM).

Methods

118 patients with schizophrenia and 160 healthy controls were recruited for the current study. The abridged version of the Cambridge Neurological Inventory (CNI) and a set of neurocognitive function tests were administered to all participants. SEM was then conducted independently in these two samples to examine the relationships between neurological soft signs and neurocognitive functions.

Results

Both the measurement and structural models showed that the models fit well to the data in both patients and healthy controls. The structural equations also showed that there were modest to moderate associations among neurological soft signs, executive attention, verbal memory, and visual memory, while the healthy controls showed more limited associations.

Conclusions

The current findings indicate that motor coordination, sensory integration, and disinhibition contribute to the latent construct of neurological soft signs, whereas the subset of neurocognitive function tests contribute to the latent constructs of executive attention, verbal memory, and visual memory in the present sample. Greater evidence of neurological soft signs is associated with more severe impairment of executive attention and memory functions. Clinical and theoretical implications of the model findings are discussed.

Neurological disorders in schizophrenia

Schizophrenia (SZ) is a complex, heterogeneous, and disabling psychiatric disorder that impairs multiple aspects of human cognitive, perceptual, emotional, and behavioral functioning. SZ is relatively frequent (prevalence around 1%), with onset usually during adolescence or early adulthood, and has a deteriorating course. The rapidly growing area of neuroimaging research has has found clear evidence of many cortical and subcortical abnormalities in individuals with SZ. In this article the most recent findings from multiple studies on neurological disorders in SZ are reviewed, and the authors make a strong argument for a neurological basis of the schizophrenic process.

Cerebellar substructures and neurological soft signs in first-episode schizophrenia

A subtle impairment of motor coordination and sensory integration functions is frequently found in schizophrenia. Clinically these deficits present as neurological soft signs (NSS). Because of its crucial role in motor function, control of muscle tone and equilibrium, the cerebellum is likely to be involved in the appearance of NSS. Magnetic resonance imaging (MRI) was performed in 30 patients with first-episode schizophrenia - all treated with atypical neuroleptics - and 21 healthy controls. NSS were rated on the Heidelberg Scale. By manual tracing, the cerebellum was divided into the following subregions bilaterally: anterior lobe, superior posterior lobe, inferior posterior lobe, and corpus medullare, respectively. Volumetric measures were compared between the two groups and related to NSS scores. NSS scores were significantly higher in patients than in controls. Cerebella of patients were significantly smaller with atrophy pronounced in the corpus medullare bilaterally. In the patients' group, higher NSS scores were found to be related to reduced volumes of the posterior lobes of the cerebellum. In contrast, no significant associations between NSS scores and cerebellar subregions in healthy subjects arose. Our findings support the hypothesis of cerebellar involvement in schizophrenia and indicate that alterations in distinct cerebellar regions are related to NSS.

Neurological soft signs in patients with schizophrenia and their unaffected siblings: frequency and correlates in two ethnic and socioeconomic distinct populations

Recent studies have suggested that ethnicity and socioeconomic status may have an impact on the frequency and significance of neurological soft signs (NSS). However, this impact has not been adequately assessed. The objectives were to determine the NSS scores in patients with schizophrenia and their unaffected siblings and to examine the clinical and therapeutic correlates of NSS in two ethnic and socioeconomic distinct populations. Two independent replicate studies were carried out: (1) a French Caucasian sample of 69 patients with schizophrenia, 43 of their unaffected siblings and 108 control subjects; (2) a Tunisian sample of 66 patients with schizophrenia, 31 of their unaffected siblings and 60 control subjects. NSS were assessed with a multidimensional scale, previously validated in drug-naïve and treated samples of patients with schizophrenia. Both patient groups were assessed with the positive and negative syndrome scale (PANSS), the clinical global impressions (CGI) and the global assessment of functioning. NSS total scores were significantly higher in patients with schizophrenia comparatively to siblings and to controls in both studies. The two sibling groups had also higher NSS scores than controls. In addition, NSS total scores were correlated to the PANSS negative and disorganization sub-scores, to the CGI-severity of illness and to a low educational level in both studies. These studies provide a confirmation in two distinct samples of the high prevalence of NSS in patients with schizophrenia, and in their biological relatives, independently of their respective ethnic and socioeconomic origins.

Potential Endophenotype for Schizophrenia: Neurological Soft Signs

Introduction: Neurological soft signs (NSS) are suggested as a candidate endophenotype for schizophrenia. This article aims to review relevant literature and discuss the role of NSS in understanding schizophrenia. Methods: This is an update on a review article published in 2003. Articles from 2003 onwards were specifically reviewed and discussed with relevance to the role of NSS as endophenotype for schizophrenia. Results: Consistent data suggest an excess of NSS in schizophrenic patients. NSS appear to be related to schizophrenic symptoms, in particular negative symptoms and disorganisation. Information on NSS and demographic correlates is scarce, and the confounding effects between age, education and intelligence on NSS constitute an important gap in current knowledge. Longitudinal data suggest NSS as both a trait and state variable in the course of disease. NSS are not specific with regard to diagnosis, although there are claims that individual sub-components may be more specific. The weight of evidence raises question on the specificity of NSS for schizophrenia. Conclusions: The usefulness and feasibility of NSS as a specific endophenotype target for schizophrenia is unclear. However, NSS remain an important feature and symptom correlate of schizophrenia. Future research should focus on delineating the effects of NSS from those of confounding demographic variables, and the stability of NSS over the course of illness to elucidate its role in schizophrenia. Key words: Diagnostic specificity, Neurological examination abnormalities, Psychotic symptoms, Review, Trait

Neurological abnormalities among offspring of persons with schizophrenia: relation to premorbid psychopathology

BACKGROUND

Neurological Examination Abnormalities (NEA, often called "neurological soft signs") have been observed in early schizophrenia and may be heritable. We investigated the prevalence, and neurocognitive and psychopathological correlates of NEA among offspring of schizophrenia patients who are at increased genetic risk for this illness.

METHODS

Neurological examinations were conducted on high risk (HR, n=74) and healthy comparison subjects (HS, n=86), using the Heinrichs-Buchanan scale. Cognitive-perceptual (CogPer) and repetitive motor (RepMot) subscores, and total NEA scores were computed. All HR and HS were assessed using K-SADS/SCID for diagnoses. Schizotypy was measured using the Magical Ideation and the Perceptual Aberration subscales (Chapman scale), attention using Continuous Performance Test (CPT-IP) and executive functions using the Wisconsin Card Sorting Test (WCST).

RESULTS

CogPer (F(1,160)=7.14, p=0.008) but not RepMot NEA scores were higher in HR subjects compared to HS after controlling for age and sex. CogPer NEA scores were higher in HR subjects with axis I psychopathology compared to those without (F(2,170)-6.41, p=0.002). HR subjects had higher schizotypy scores (composite of the magical ideation and perceptual aberration scales) (F(1,141)=23.25, p=0.000004). Schizotypy scores were negatively correlated with sustained attention and executive functions. In addition, schizotypy was positively correlated with CogPer NEA scores.

CONCLUSIONS

Young relatives at increased genetic risk for schizophrenia show more frequent NEA. CogPer but not RepMot NEA scores were elevated, consistent with our prior observation of CogPer NEA being relatively specific for schizophrenia. The observed relationships between NEA, cognitive impairments, schizotypy and axis I disorders suggest that NEA may characterize a subgroup of HR offspring at an elevated risk for psychopathology.

Psychomotor slowing in schizophrenia

Psychomotor slowing (PS) is a cluster of symptoms that was already recognized in schizophrenia by its earliest investigators. Nevertheless, few studies have been dedicated to the clarification of the nature and the role of the phenomenon in this illness. Moreover, slowed psychomotor functioning is often not clearly delineated from reduced processing speed. The current, first review of all existing literature on the subject discusses the key findings. Firstly, PS is a clinically observable feature that is most frequently established by neuropsychological measures assessing speed of fine movements such as writing or tasks that require rapid fingertip manipulations or the maintenance of maximal speed over brief periods of time in manual activities. Moreover, the slowed performance on the various psychomotor measures has been demonstrated independent of medication and has also been found to be associated with negative symptoms and, to a lesser extent, with positive and depressive symptoms. Importantly, performance on the psychomotor tasks proved related to the patients' social, clinical, and functional outcomes. Several imaging studies showed slowed performance to coincide with dopaminergic striatal activity. Finally, conventional neuroleptics do not improve the patients' PS symptoms, in contrast to the atypical agents that do seem to produce modestly improving effects.

Comparative study of neurological soft signs in schizophrenia with onset in childhood, adolescence and adulthood

OBJECTIVE

To compare neurological soft signs (NSS) in patients of schizophrenia with onset in childhood (COS), adolescence (AdOS) and adulthood (AOS).

METHOD

Assessment of NSS in 15 patients of COS and 20 patients each of AdOS and AOS was made using condensed neuropsychiatric examination for NSS.

RESULTS

NSS were significantly more frequent in COS (100%) and AdOS (90%) when compared with AOS (55%) patients. COS patients showed significantly higher scores on temporal and frontal lobe NSS, of which differences between the three groups in temporal lobe NSS disappeared on ancova. Parietal lobe dependent NSS were seen in a few COS patients. The NSS were more in those with lesser IQ, lower education and higher Positive and Negative Syndrome Scale scores.

CONCLUSION

Findings indicate that earlier onset types may be more strongly associated with a generalized disruption of brain function. Non-suppression of primitive reflexes with cortical maturation in COS point towards disordered neurodevelopment. Preponderance of fronto-temporal and a relative lack of parietal lobe NSS point towards differential lobar involvement. Neurodevelopmental abnormalities leading to NSS also lead to lower IQ and lower educational level.

Obstetric complications and neurological abnormalities in neuroleptic-naive psychotic patients

Studies addressing the relationship between a history of obstetric complications (OCs) and neurological abnormalities in schizophrenia have produced contradictory findings. Using a pre-posttreatment design in a neuroleptic-naive sample of psychotic patients, we examined the relationship of a history of OC to primary and drug-induced neurological signs. Fifty neuroleptic-naive non-affective psychotic inpatients were assessed for a history of OC by using the McNeil-Sjöström scale, and for neurological signs including parkinsonism, dyskinesia, akathisia and catatonia, which were rated before and after inception of neuroleptic treatment. A subsample of 28 patients were also examined for neurological soft-signs. Ratings of OCs were related to admission levels of parkinsonism, dyskinesia, akathisia and neurological soft-signs, but not to levels of catatonia. By obstetric period, pregnancy complications were related to levels of parkinsonism, dyskinesia, and neurological soft-signs, and neonatal complications were related to levels of akathisia. Drug-induced neurological signs were not associated with a history of OCs. We argue that the association pattern between a history of OCs and primary neurological signs from several domains suggests a causal link among these variables. Having a history of OCs does not convey a vulnerability for developing drug-induced neurological signs in the short term.

Are neurologic examination abnormalities heritable? A preliminary study

BACKGROUND

Neurologic examination abnormalities (NEA) are more prevalent among patients with schizophrenia as well as their unaffected relatives when compared with healthy controls, suggesting that NEA may be endophenotypes for schizophrenia. We estimated the heritability of NEA in moderately sized pedigrees. We also evaluated correlations between NEA and cognitive performance in order to examine their construct validity.

METHODS

Members of eight extended families, each consisting of two first degree relatives with schizophrenia/schizoaffective disorders, as well as available first- to fifth-degree relatives were examined (n=96 participants). A modification of the Neurological Evaluation Scale (NES) was employed, augmented with localizing signs. Where feasible, we used untransformed data such as error counts and completion time, rather than ordinal measures. Heritability was estimated using the variance component method, implemented in SOLAR.

RESULTS

Statistically significant heritability (h2) estimates were obtained for several measures (p<0.05, h2+/-standard error: rapid alternating movements, right-sided completion time, 0.99+/-0.19; alternating fist-palm test, completion time, 0.77+/-0.19 s, errors, 0.70+/-0.32; fist-ring test, right-sided completion time, 0.53+/-0.23 s, left-sided completion time, 0.70+/-0.21 s; go-no go task, correct responses, 0.93+/-0.33; audio-visual integration, correct responses, 0.79+/-0.54). For most items, heritability analysis was hampered by insufficient data variability (infrequent errors). Correlational analyses show some degree of divergence among types of NEA, repetitive motor tasks being associated with most domains of cognitive functioning other than executive functioning, and cognitive-perceptual tasks being associated with memory and executive functioning.

CONCLUSIONS

Significant familial influences on certain aspects of neurologic performance were detected. These heritable measures were also correlated with heritable neurocognitive measures.

Mental rotation in schizophrenia

Motor imagery provides a direct insight into action representations. The aim of the present study was to investigate the level of impairment of action monitoring in schizophrenia by evaluating the performance of schizophrenic patients on mental rotation tasks. We raised the following questions: (1) Are schizophrenic patients impaired in motor imagery both at the explicit and at the implicit level? (2) Are body parts more difficult for them to mentally rotate than objects? (3) Is there any link between the performance and the hallucinating symptom profile? The schizophrenic patients (n = 13) displayed the same pattern of performance as the control subjects (n = 13). More particularly, schizophrenic patients' reaction time varied as a function of the angular disparity of the stimuli. On the other hand, they were significantly slower and less accurate. Interestingly, patients suffering from hallucinations made significantly more errors than non-hallucinatory patients. We discussed these latter results in terms of deficit of the forward model. We emphasized the necessity to distinguish different levels of action, more or less impaired in schizophrenia.

The dual origin hypothesis: An evolutionary brain-behavior framework for analyzing psychiatric disorders

According to the dual origin hypothesis, the cerebral cortex of higher mammals evolved from two primordial brain structures, the amygdala and hippocampal formation. This developmental process defines the orderly principles of cortical connectivity and gives rise to functionally distinct ventral and dorsal systems within the cerebrum. This paper reviews the basic features of the dual origin theory. This model is then applied to understanding symptom production in a number of psychiatric illnesses, with particular reference to recent structural and functional imaging studies. In this paper I propose that psychiatric symptoms can be conceptualized as arising from abnormal processing within dorsal (time-space-motility) or ventral (meaning-motivation) systems, or from a disturbance in the functional interaction/balance between them. Within this framework, one can identify symptom-specific correlations that cross-traditional diagnostic boundaries, as well as potential mechanisms that may explain biologically valid diagnostic entities. Integrating evolutionary, connectional and functional bases across multiple species, the dual origin hypothesis offers a powerful neural systems model to help organize our understanding of psychiatric illness, therein suggesting novel approaches to diagnosis, prevention and treatment.

Neurologic soft signs in schizophrenic patients treated with conventional and atypical antipsychotics

Neurologic soft signs (NSS) are considered a somatic feature associated with schizophrenia (DSM-IV) that are present in neuroleptic-treated, as well as untreated or first-episode patients. The aim of this study was to determine the incidence and severity of NSS in groups of schizophrenic patients treated with either a conventional neuroleptic medication, haloperidol (n = 37), or atypical antipsychotic medications, risperidone (n = 19), clozapine (n = 34), and olanzapine (n = 18). NSS were assessed with the Neurological Evaluation Scale (NES), whereas extrapyramidal symptoms (EPS), which occur more commonly with conventional neuroleptic treatment, were evaluated using the Simpson-Angus Scale. NES scores were not significantly different between groups. Slight differences were found for 2 items only. The haloperidol group showed higher scores for the "Romberg test," whereas the clozapine group showed higher scores for "short-term memory." There were significant correlations between EPS and NES total score in the haloperidol and risperidone groups. These results demonstrate an overall overlapping of NSS among the groups, confirming their substantial independence from neurologic implications of neuroleptic treatment.

Neurological abnormalities in first-episode schizophrenia: temporal stability and clinical and outcome correlates

OBJECTIVE

Neurological abnormalities in subjects with schizophrenia have been regarded as diagnostically non-specific and non-localising. This study assessed the temporal stability of neurological abnormalities in subjects with first-episode schizophrenia over the course of 12 months. We also examined their relationships with psychiatric symptoms, medication effects and treatment outcome.

METHOD

The sample comprised 66 largely medication-naive subjects who were treated according to a fixed protocol. We performed a factor analysis of the Neurological Evaluation Scale (NES) items, and relationships between the NES factors and various clinical and outcome measures were explored.

RESULTS

Five NES factors were identified, explaining 68.4% of the variance. While the NES total scores did not change significantly over time, poor performance on motor sequencing tests was related to longer duration of untreated psychosis, and showed a tendency to improve as psychiatric symptoms resolved. The most interesting finding was that high scores on the motor sequencing factor predicted the emergence of persistent dyskinesia at 24 months (ANCOVAR F(1, 20) = 19.287, p = 0.0002).

CONCLUSIONS

Two NES factors (motor sequencing and attention) are reasonably replicable across samples, and have potential relevance for the further exploration of the pathogenesis of schizophrenia, as well as possible clinical applications.

Cortical release signs in psychiatry

OBJECTIVE

To review the role of cortical release signs (CRS) in neuropsychiatry.

METHOD

A thorough literature review was conducted using Medline and Psychlit databases, and other relevant references available to the authors.

RESULTS

A number of neurological abnormalities are reported at elevated rates in neuropsychiatric conditions. CRS are a group of primitive reflexes that are present in the neonate but become inhibited as the infant central nervous system (CNS) develops, only to later re-emerge in the context of CNS disease. The clinical elicitation and interpretation of each CRS is described with reference to its neurobiology. The prevalence of CRS in schizophrenia, affective disorder, obsessive-compulsive disorder, Alzheimer's disease, vascular dementia, frontotemporal dementia and other neuropsychiatric illness allows for their use in the clinical management of these patients, including diagnostic assessment, treatment monitoring and prognosis.

CONCLUSIONS

A number of issues complicate their interpretation in neuropsychiatric illness, including the apparent high base rate of some CRS in non-clinical populations, their increasing prevalence with age, lack of specificity and uncertainty over what constitutes an 'abnormal' response. In some circumstances, CRS may assist in diagnostic differentiation and illness staging.

Cerebellar dysfunction in neuroleptic naive schizophrenia patients: clinical, cognitive, and neuroanatomic correlates of cerebellar neurologic signs

BACKGROUND

There is increasing evidence that, aside from motor coordination, the cerebellum also plays an important role in cognition and psychiatric disorders. Our previous studies support the hypothesis that cerebellar dysfunction may disrupt the cortico-cerebellar-thalamic-cortical circuit and, in turn, lead to cognitive dysmetria in schizophrenia. The goal of this study was to investigate cerebellar dysfunction in schizophrenia by examining the clinical, cognitive, and neuroanatomic correlates of cerebellar neurologic signs in schizophrenia patients.

METHODS

We compared the prevalence of cerebellar neurologic signs in 155 neuroleptic-naive schizophrenia patients against 155 age- and gender-matched healthy control subjects. Differences in clinical characteristics, standardized neuropsychologic performance, and magnetic resonance imaging brain volumes between patients with and without cerebellar signs were also examined.

RESULTS

Patients had significantly higher rates of cerebellar signs than control subjects, with coordination of gait and stance being the most common abnormalities. Patients with lifetime alcohol abuse or dependence were no more likely than those without alcoholism to have cerebellar signs. Presence of cerebellar signs in patients was associated with poorer premorbid adjustment, more severe negative symptoms, poorer cognitive performance, and smaller cerebellar tissue volumes.

CONCLUSIONS

These findings lend further support for cerebellar dysfunction in schizophrenia.

Schizophrenia: etiology and course

Decades of research on schizophrenia have not produced major breakthroughs, but gradual progress has been made in identifying risk factors and clarifying the nature of the etiologic process. This article provides an overview of trends in research findings as well as current assumptions about the interplay between environmental and genetic factors in the etiology of schizophrenia. Based on the cumulative findings, it appears that both genetic and prenatal factors can give rise to constitutional vulnerability. Subsequent neuromaturational processes, especially those that occur during adolescence, and exposure to stressful events can trigger the behavioral expression of this vulnerability.

A pilot neuropsychological study of Kraepelinian and non-Kraepelinian schizophrenia

OBJECTIVE

This is the first study to report a direct comparison of neuropsychological performance in Kraepelinian vs. non-Kraepelinian schizophrenia (SZ).

METHODS

17 Kraepelinian and 19 non-Kraepelinian subjects were assessed on a neuropsychological battery including the Purdue Pegboard, Schwartz' Reaction Time task, the Modified Card Sorting Test, the Wechsler's Associate Learning Test and the Digit Span.

RESULTS

Kraepelinian schizophrenia was characterized by more impaired performance on the Purdue Pegboard and the Card Sorting test. These differences remained significant when introducing, as covariates, the type of neuroleptic used, the use of anticholinergic medication, age and gender. Differences on the Reaction Time, the Associate Learning and the Digit Span tasks did not reach statistical significance.

CONCLUSIONS

These results suggest that Kraepelinian schizophrenia is characterized by impaired performance on fine motor dexterity and executive functioning. These results further add to the evidence for the validity of the distinction between Kraepelinian and non-Kraepelinian schizophrenia as a strategy to better understand the factors influencing severity and/or outcome in schizophrenia.