Scientific Evidence for the Evaluation of Neurological Soft Signs as Atypical Neurodevelopment Markers in Childhood Neuropsychiatric Disorders

Neurodevelopmental predictors of treatment response in schizophrenia and bipolar disorder

BACKGROUND

Treatment resistance is a major challenge in psychiatric disorders. Early detection of potential future resistance would improve prognosis by reducing the delay to appropriate treatment adjustment and recovery. Here, we sought to determine whether neurodevelopmental markers can predict therapeutic response.

METHODS

Healthy controls (N = 236), patients with schizophrenia (N = 280) or bipolar disorder (N = 78) with a known therapeutic outcome, were retrospectively included. Age, sex, education, early developmental abnormalities (obstetric complications, height, weight, and head circumference at birth, hyperactivity, dyslexia, epilepsy, enuresis, encopresis), neurological soft signs (NSS), and ages at first subjective impairment, clinical symptoms, treatment, and hospitalization, were recorded. A supervised algorithm leveraged NSS and age at first clinical signs to classify between resistance and response in schizophrenia.

RESULTS

Developmental abnormalities were more frequent in schizophrenia and bipolar disorder than in controls. NSS significantly differed between controls, responsive, and resistant participants with schizophrenia (5.5 ± 3.0, 7.0 ± 4.0, 15.0 ± 6.0 respectively, p = 3 × 10-10) and bipolar disorder (5.5 ± 3.0, 8.3 ± 3.0, 12.5 ± 6.0 respectively, p < 1 × 10-10). In schizophrenia, but not in bipolar disorder, age at first subjective impairment was three years lower, and age at first clinical signs two years lower, in resistant than responsive subjects (p = 2 × 10-4 and p = 9 × 10-3, respectively). Age at first clinical signs and NSS accurately predicted treatment response in schizophrenia (area-under-curve: 77 ± 8%, p = 1 × 10-14).

CONCLUSIONS

Neurodevelopmental features such as NSS and age of clinical onset provide a means to identify patients who may require rapid treatment adaptation.

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

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

The impact of Toxocara-seropositivity on attention and motor skills in children with attention-deficit hyperactivity disorder

BACKGROUND

The study aims to compare neurological soft signs and executive functions between Toxocara-seropositive and seronegative groups in children with attention-deficit/hyperactivity disorder.

METHODS

The study included 60 boys with ADHD, aged 7-12. After blood samples were taken, the Stroop Color Word Test and Judgment of Line Orientation test (JLOT) were implemented to measure executive functions. Neurological soft signs were evaluated with Physical and Neurological Examination for Subtle Signs (PANESS).

RESULTS

Serological tests were positive for Toxocara antibodies in 20 cases. There was no significant difference between Toxocara seropositive and seronegative regarding age, socioeconomic status, developmental stages, and ADHD severity. However, Toxocara-seropositive children had higher Stroop time and Stroop interference scores and lower JLOT scores than Toxocara-seronegative children. Furthermore, Toxocara-seropositive children exhibited more neurological soft signs, such as gait and station abnormalities, dysrhythmia, and a longer total time in timed movements compared to Toxocara-seronegative children.

CONCLUSION

Our study indicates a link between Toxocara-seropositivity and impaired neurological soft signs and executive functions in ADHD. Further research is needed to understand ADHD mechanisms, develop practical treatments considering immunological factors, and thoroughly evaluate how Toxocara seropositivity affects executive functions and motor skills in children with ADHD.

Associations between neurological soft signs, executive functions, and brain-derived neurotrophic factor in boys with attention-deficit hyperactivity disorder

Background

To determine the association between neurological soft signs, executive functions, and serum brain-derived neurotrophic factor (BDNF) levels in children with attention-deficit hyperactivity disorder (ADHD).

Methods

Serum BDNF levels were measured in 87 drug-naive boys with ADHD, aged 7-12 years. The Revised Physical and Neurological Examination for Subtle Signs for neurological soft signs, Stroop Color-Word Test for attention functions, and Judgment of Line Orientation Test (JLOT) for visuospatial abilities were performed.

Results

Age correlated negatively with dysrhythmia, total time, and total overflow in timed movements, Stroop Color-Word Time (SCWT), and serum BDNF levels. The JLOT significantly negatively correlated with Total Gaits and Stations (P1) and Total Time in Timed Movements (adjusted R 2 = 0.247). In addition, SCWT maintained a significant correlation with Total Overflow in Timed Movements (adjusted R 2 = 0.206). There was no correlation between serum BDNF levels and NSS.

Conclusion

The association between NSS, visuospatial abilities, and selective attention may express a maturational delay in ADHD pathophysiology. Moreover, BDNF may play a role in this maturational delay. Future studies should investigate the contribution of BDNF to neuronal maturation in ADHD.

Prevalence of Neurological Soft Signs at Presentation in Pediatric Acute-Onset Neuropsychiatric Syndrome

Importance

Studies of brain imaging and movements during REM sleep indicate basal ganglia involvement in pediatric acute-onset neuropsychiatric syndrome (PANS). Characterizing neurological findings commonly present in patients with PANS could improve diagnostic accuracy.

Objective

To determine the prevalence of neurological soft signs which may reflect basal ganglia dysfunction (NSS-BG) in youth presenting with PANS and whether clinical characteristics of PANS correlate with NSS-BG. Design, Setting, and Participants: 135 new patients who were evaluated at the Stanford Children's Immune Behavioral Health Clinic between November 1, 2014 and March 1, 2020 and met strict PANS criteria were retrospectively reviewed for study inclusion. 16 patients were excluded because they had no neurological exam within the first three visits and within three months of clinical presentation.

Main Outcomes and Measures

The following NSS-BG were recorded from medical record review: 1) glabellar tap reflex, 2) tongue movements, 3) milkmaid's grip, 4) choreiform movements, 5) spooning, and 6) overflow movements. We included data from prospectively collected symptoms and impairment scales.

Results

The study included 119 patients: mean age at PANS onset was 8.2 years, mean age at initial presentation was 10.4 years, 55.5% were male, and 73.9% were non-Hispanic White. At least one NSS-BG was observed in 95/119 patients (79.8%). Patients had 2.1 NSS-BG on average. Patients with 4 or more NSS-BG had higher scores of global impairment (p=0.052) and more symptoms (p=0.008) than patients with 0 NSS-BG. There was no significant difference in age at visit or reported caregiver burden. On Poisson and linear regression, the number of NSS-BG was associated with global impairment (2.857, 95% CI: 0.092-5.622, p=0.045) and the number of symptoms (1.049, 95% CI: 1.018-1.082, p=0.002), but not age or duration of PANS at presentation.

Conclusions and Relevance

We found a high prevalence of NSS-BG in patients with PANS and an association between NSS-BG and disease severity that is not attributable to younger age. PANS may have a unique NSS-BG profile, suggesting that targeted neurological exams may support PANS diagnosis.

Neurological soft signs in adolescents are associated with brain structure

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

Disorganization domain as a putative predictor of Treatment Resistant Schizophrenia (TRS) diagnosis: A machine learning approach

BACKGROUND

Treatment Resistant Schizophrenia (TRS) is the persistence of significant symptoms despite adequate antipsychotic treatment. Although consensus guidelines are available, this condition remains often unrecognized and an average delay of 4-9 years in the initiation of clozapine, the gold standard for the pharmacological treatment of TRS, has been reported. We aimed to determine through a machine learning approach which domain of the Positive and Negative Syndrome Scale (PANSS) 5-factor model was most associated with TRS.

METHODS

In a cross-sectional design, 128 schizophrenia patients were classified as TRS (n = 58) or non-TRS (n = 60) after a structured retrospective-prospective analysis of treatment response. The random forest algorithm (RF) was trained to analyze the relationship between the presence/absence of TRS and PANSS-based psychopathological factor scores (positive, negative, disorganization, excitement, and emotional distress). As a complementary strategy to identify the variables most associated with the diagnosis of TRS, we included the variables selected by the RF algorithm in a multivariate logistic regression model.

RESULTS

according to the RF model, patients with higher disorganization, positive, and excitement symptom scores were more likely to be classified as TRS. The model showed an accuracy of 67.19%, a sensitivity of 62.07%, and a specificity of 71.43%, with an area under the curve (AUC) of 76.56%. The multivariate model including disorganization, positive, and excitement factors showed that disorganization was the only factor significantly associated with TRS. Therefore, the disorganization factor was the variable most consistently associated with the diagnosis of TRS in our sample.

The role of neurological soft signs in different mathematical skills in second and third grade children

Neurological soft signs (NSSs) are subtle motor and sensory deficits, and are associated with poor cognitive abilities. Although cognitive ability has been found to be a significant predictor for academic performance in children, it remains unclear whether NSSs could contribute to academic abilities such as mathematical skills, and its contribution varies according to grade level. Therefore, in this cross-sectional study, we examined the relationships between NSSs and different mathematical skills (calculation fluency, numerical operations, and mathematical problem-solving) in 105 Chinese children (Mean age = 7.76 years, SD age = 0.67 years; 52 from second grade, 53 from third grade; 56 boys and 49 girls) recruited from a primary public school located in Shanghai. The results of regression analyses revealed that NSSs significantly predicted calculation fluency (β = -.32, p < .050), numerical operations (β = -.38, p < .050), and mathematical problem-solving (β = -0.40, p < .010) in second but not third grade, even controlling for cognitive processes. Our results implicate that NSSs could be a potential predictor for mathematical skills in the early years of primary school.

Motor cortex modulation and reward in children with attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder, the most prevalent developmental disorder in childhood, is a biologically heterogenous condition characterized by impaired attention and impulse control as well as motoric hyperactivity and anomalous motor skill development. Neuropsychological testing often demonstrates impairments in motivation and reward-related decision making in attention-deficit/hyperactivity disorder, believed to indicate dysfunction of the dopamine reward pathway. Development of reliable, non-invasive, easily obtained and quantitative biomarkers correlating with the presence and severity of clinical symptoms and impaired domains of function could aid in identifying meaningful attention-deficit/hyperactivity disorder subgroups and targeting appropriate treatments. To this end, 55 (37 male) 8–12-year-old children with attention-deficit/hyperactivity disorder and 50 (32 male) age-matched, typically-developing controls were enrolled in a transcranial magnetic stimulation protocol—used previously to quantify cortical disinhibition in both attention-deficit/hyperactivity disorder and Parkinson’s Disease—with a child-friendly reward motivation task. The primary outcomes were reward task-induced changes in short interval cortical inhibition and up-modulation of motor evoked potential amplitudes, evaluated using mixed model, repeated measure regression. Our results show that both reward cues and reward receipt reduce short-interval cortical inhibition, and that baseline differences by diagnosis (less inhibition in attention-deficit/hyperactivity disorder) were no longer present when reward was cued or received. Similarly, both reward cues and reward receipt up-modulated motor evoked potential amplitudes, but, differentiating the two groups, this Task-Related-Up-Modulation was decreased in children with attention-deficit/hyperactivity disorder. Furthermore, more severe hyperactive/impulsive symptoms correlated significantly with less up-modulation with success in obtaining reward. These results suggest that in children with attention-deficit/hyperactivity disorder, short interval cortical inhibition may reflect baseline deficiencies as well as processes that normalize performance under rewarded conditions. Task-Related-Up-Modulation may reflect general hypo-responsiveness in attention-deficit/hyperactivity disorder to both reward cue and, especially in more hyperactive/impulsive children, to successful reward receipt. These findings support transcranial magnetic stimulation evoked cortical inhibition and task-induced excitability as biomarkers of clinically relevant domains of dysfunction in childhood attention-deficit/hyperactivity disorder.

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

OBJECTIVE

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

PATIENTS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Functional and structural asymmetry in primary motor cortex in Asperger syndrome: a navigated TMS and imaging study

Motor functions are frequently impaired in Asperger syndrome (AS). In this study, we examined the motor cortex structure and function using navigated transcranial magnetic stimulation (nTMS) and voxel-based morphometry (VBM) and correlated the results with the box and block test (BBT) of manual dexterity and physical activity in eight boys with AS, aged 8–11 years, and their matched controls. With nTMS, we found less focused cortical representation areas of distinct hand muscles in AS. There was hemispheric asymmetry in the motor maps, silent period duration and active MEP latency in the AS group, but not in controls. Exploratory VBM analysis revealed less gray matter in the left postcentral gyrus, especially in the face area, and less white matter in the precentral area in AS as compared to controls. On the contrary, in the right leg area, subjects with AS displayed an increased density of gray matter. The structural findings of the left hemisphere correlated negatively with BBT score in controls, whereas the structure of the right hemisphere in the AS group correlated positively with motor function as assessed by BBT. These preliminary functional (neurophysiological and behavioral) findings are indicative of asymmetry, and co-existing structural alterations may reflect the motor impairments causing the deteriorations in manual dexterity and other motor functions commonly encountered in children with AS.