3,135 research outputs found

    The cerebellum and motor dysfunction in neuropsychiatric disorders

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    The cerebellum is densely interconnected with sensory-motor areas of the cerebral cortex, and in man, the great expansion of the association areas of cerebral cortex is also paralleled by an expansion of the lateral cerebellar hemispheres. It is therefore likely that these circuits contribute to non-motor cognitive functions, but this is still a controversial issue. One approach is to examine evidence from neuropsychiatric disorders of cerebellar involvement. In this review, we narrow this search to test whether there is evidence of motor dysfunction associated with neuropsychiatric disorders consistent with disruption of cerebellar motor function. While we do find such evidence, especially in autism, schizophrenia and dyslexia, we caution that the restricted set of motor symptoms does not suggest global cerebellar dysfunction. Moreover, these symptoms may also reflect involvement of other, extra-cerebellar circuits and detailed examination of specific sub groups of individuals within each disorder may help to relate such motor symptoms to cerebellar morphology

    Bio-social aspects of Attention Deficit Hyperactivity Disorder (ADHD): Neurophysiology, maturity, motor function and how symptoms relate to family interaction

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    The purpose of this thesis has been to study biological and social factors of importance for Attention Deficit Hyperactivity Disorder (ADHD). Thirty children (age 6-11) with ADHD were examined with parent ratings, neurological examination, cognitive testing, cerebral blood-flow, and EEG. These children together with 14 other children the same age with ADHD, were video-taped during family-tasks before and after three months of treatment with amphetamine. Parents answered questionnaires concerning family functioning and parental well-being. Two-hundred and fifty-one children (age 6-9) were examined with skeletal bone-age, motor examination by the physical education teacher, and parent and teacher questionnaires concerning ADHD-symptoms. Thirty-five children were video-taped during neurological examination. Twenty children were examined on two occasions with four weeks between the examinations. Eighty-nine children age 5½, and 23 children age 7-9 underwent neurological examination and parents were interviewed concerning their child’s motor development. The results from the examination of cerebral blood-flow suggest that there may be at least two functional disturbances in children with ADHD, one involving the frontal lobes, especially on the right side, related to behavioural deviance, and another disturbance of the integration of the temporal lobes, the cerebellum and subcortical structures related to motor planning and aspects of cognition. The study of family function gives support to the notion that some aspects of family dysfunction may be related to the child’s ADHD behaviour. Variables related to general biological maturity did not correlate with ADHD-symptoms. The neurological “soft-signs” examination studied, was found to have good reliability and validity as a measure of motor function and can be recommended for clinical practice and research

    New Insights on the Effects of Methylphenidate in Attention Deficit Hyperactivity Disorder

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    This narrative review describes an overview of the multiple effects of methylphenidate (MPH) in attention-deficit/hyperactivity disorder (ADHD) and its potential neurobiological targets. It addressed the following aspects: 1) MPH effects on attention and executive functions in ADHD; 2) the relation between MPH efficacy and dopamine transporter gene (DAT) polymorphism; and 3) the role of MPH as an epigenetic modulator in ADHD. Literature analysis showed that MPH, the most commonly used psychostimulant in the therapy of ADHD, acts on multiple components of the disorder. Marked improvements in attentional and executive dysfunction have been observed in children with ADHD during treatment with MPH, as well as reductions in neurological soft signs. MPH efficacy may be influenced by polymorphisms in the DAT, and better responses to treatment were associated with the 10/10 genotype. Innovative lines of research have suggested that ADHD etiopathogenesis and its neuropsychological phenotypes also depend on the expression levels of human endogenous retrovirus (HERV). In particular, several studies have revealed that ADHD is associated with HERV-H over-expression and that MPH administration results in decreased expression levels of this retroviral family and a reduction in the main symptoms of the disorder. In conclusion, there is a confirmed role for MPH as an elective drug in the therapy of ADHD alone or in association with behavioral therapy. Its effectiveness can vary based on DAT polymorphisms and can act as a modulator of HERV-H gene expression, pointing to targets for a precision medicine approach

    Neurological soft signs in adolescents are associated with brain structure and postural control

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    Neurological soft signs (NSS) are minor deviations from the norm in sensory and motor performance. NSS exist in the general population but are more frequently found in cohorts with neurodevelopmental disorders. NSS are considered a diffuse and unspecific marker of altered neurodevelopment but receive increasing attention since the presence of NSS in children has been found to be predictive of psychiatric disorders in late adolescence. To date, only little is known about potential neurodevelopmental alterations that may underlay the presence of NSS. The prevalence of NSS has been shown to decrease during adolescence as part of continued neural development and brain re-wiring processes. Therefore, adolescence has been proposed as an important phase for the manifestation or outgrowing of NSS. The underlying mechanisms that may underly this process, however, are largely unknown. As NSS are subtle signs and commonly identified by subjective observer-based neurological examinations, quantitative tools may help to objectively investigate functional and structural correlates associated with NSS. For the work included in this dissertation, healthy adolescent athletes from three European countries were investigated. All participants underwent a neurological examination, resulting in a categorization of participants into groups with and without NSS (NSS+/NSS-). A total NSS score was calculated to provide a continuous measure spanning the whole spectrum of NSS. Two quantitative tools were used to investigate functional and structural correlates of NSS in healthy adolescents: Study I) Instrumented force plate measures to investigate postural control (Bonke et al., 2023), and Study II) Structural magnetic resonance imaging to investigate brain morphology and white matter microstructure (Bonke et al., 2022). Study I aimed to investigate the incremental value of instrumented force plate measures in addition to observer-based neurological examinations. Such associations have not been assessed before but are important for capturing subtle alterations in postural control. This will help to acquire a more comprehensive assessment of motor development. We found no statistically significant differences in postural control between NSS+ and NSS- group. However, participants performing non-optimal in the diadochokinesis sub-test measuring pronation/supination of forearms showed significantly reduced postural control in the medial-lateral (ML) direction. Moreover, the total NSS score correlated significantly with postural control performance in the ML direction. Findings from this study reveal that adolescents with NSS, and in particular adolescents that perform non-optimal in pronation/supination movements of the forearms also perform worse in ML postural control assessed by force plate assessments. As pronation/supination movements of forearms and ML postural control continue to mature until adolescence, it can be assumed that these functions are related and may indicate altered motor development. Study II aimed to identify and characterize NSS-related brain structure alterations using structural magnetic resonance imaging. NSS-related brain structure alterations have not yet been investigated in healthy adolescents. However, this investigation is of high relevance to better understand potential alterations in adolescent brain-rewiring processes related to NSS. Using T1-weighted imaging, we found significantly higher gyrification in the left superior frontal and parietal lobe in the group of adolescents with NSS, likely reflecting alterations in synaptic pruning. We did not find differences in cortical volume or thickness. Using diffusion tensor imaging, we found lower tissue fractional anisotropy (FAt) and higher tissue radial diffusivity (RDt) in widespread white matter clusters in the group of adolescents with NSS, likely indicating alterations in myelination. Findings from this study reveal that NSS in healthy adolescents are associated with brain structure alterations that can be objectively quantified using magnetic resonance imaging. As of now, the relevance of NSS-related brain structure alterations in otherwise healthy adolescents is not fully understood. Future studies should assess whether these alterations may explain the described association between NSS and psychiatric disorders. In summary, the work presented in this doctoral dissertation uses two different quantitative measures to objectively investigate functional and structural differences between adolescents with and without NSS. Insights derived from this work show the beneficial use of instrumented tools to complement neurological examinations for a better understanding of functional and structural correlates of NSS. This work will help to generate a more complete picture of NSS-related developmental alterations and potentially related psychiatric vulnerabilities. Future research should make use of larger and more representative datasets to replicate, as well as extend our findings. Specific attention should be drawn on the investigation of factors that contribute to the development of NSS, longitudinal studies that allow to capture NSS-related alterations in developmental trajectories, as well as on investigating the underlying neural mechanisms of NSS

    Quantified Observations of Sensory Processing (QOSP): Resource Tool for Screening Sensory Processing Difficulties in Preschoolers

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    Sensory Processing (SP) difficulties in children are seen to be increasing in today's world. Quite a few typically developing children are reported to have difficulties in coping with school, home and play environments. Their difficulties are mostly labeled abnormal behaviors and with superficial assessments these children often receive traditional treatments that marginally decrease their problems without giving long term functional gains. Hence their SP dysfunctions make them adopt pathological behaviors as they grow, making them incompetent as compared to their peers.One of the factors behind these children getting unnoticed at an early age is lack of awareness about SP difficulties among the parents, teachers and medical fraternity in India. The other important factors include unavailability of contributory study in this area done on the Indian population and the use of non-normated, generalized evaluation tools done for evaluation of these difficulties. Further less information on what is age related typical SP makes it trickier to differentiate between a typical behavior and SP difficulty. The present study is the first study that would make an effort to understand the age related SP in Indian preschoolers aged 3-7 years.The QOSP includes observations based on literature and theoretical constructs of SP which are graded and made quantitative for ease of administration and interpretation. This study intends to establish the age appropriate expected response and estimate the children posing risk to develop SP dysfunctions. The study further attempts to understand correlations between the different parameters of QOSP and tries to identify those parameters that can be considered red flags for SP difficulties.The results of the study suggest about 3% of children in the typically developing group to be at the risk of having SP difficulties. About 20% are estimated to be having difficulties in at least one of the SP areas when compared with behaviors rated on Sensory Processing Measure. Apart from typically developing children the tool was also used in co-morbid conditions and was found to be useful in understanding the underlying Sensory Processing difficulties. Thus the QOSP can be considered a good measure not only in screening children with suspected sensory processing difficulties but also to gear the intervention program to be streamlined and goal oriented

    Motor activity measured by actometry in neuropsychiatric disorders

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    A study on comparison of neurological soft signs and minor physical anomalies between siblings of attention deficit hyperactivity disorder children and normal controls.

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    INTRODUCTION Attention deficit hyperactivity disorder is the most common neurobehavioural disorder of the childhood. It is characterised by inattention, hyperactivity and impulsivity. Neurological Soft Signs represent subtle neurological signs that could not be localised to a particular region of brain. Minor Physical Anomalies are subtle phenotypic abnormalities that don’t fit into dysmorphic syndromes. Both the NSS and MPA indicate a diffuse brain injury. And both are present in many of psychiatric disorders and behavioural disorders especially ADHD. AIMS & OBJECTIVES To study the Neurological Soft Signs and Minor Physical Anomalies in ADHD siblings in comparison with age matched controls. To study the correlations of Neurological Soft Signs and Minor Physical anomalies with respect to gender and socioeconomic class of the children. To study the interrelationship between various domains of soft signs with minor physical Anomalies. SUBJECTS AND METHODS Study was conducted in child psychiatry department. Siblings of the children diagnosed of ADHD during the study period, who doesn’t have a feature of neurological or psychiatric abnormality including ADHD, from 8 to 13 years were included in the case group. Normal children were included in the control group. The number of children included in both case and control group were 57. The children included in the study were given revised Physical and Neurological Evaluation of Soft Signs (PANESS) and WALDROP Minor Physical Anomaly Scale and scores were assessed. STATISTICAL ANALYSIS The scores of various domains of Neurological Soft Signs and Minor Physical Anomalies were drawn. Independent t test were applied between the two groups. P <0.05 were taken as significant. Similarly correlations were drawn among gender and socioeconomic class with NSS/MPA by Pearson’s correlation. Statistical analysis were done by SPSS version 17.0. RESULTS Total number of children included in the study was 114. Of that 74 were male and 40 were female. Socio economic class was obtained for each child by modified kuppusamy scale. There is a statistical significance of p< 0.05 in overflow items, gaits and stations, total timed and total PANESS. p> 0.05is noted for minor physical anomalies for both case and control group. There is no statistical difference for males and females for NSS/MPA separately for both the case and control group. There is a positive correlation for overflow items & timed movements with minor physical anomalies for ADHD siblings in lower middle and upper lower socioeconomic groups. CONCLUSION ADHD siblings showed a significant increase in Neurological soft Signs when compared with normal children. While ADHD siblings fail to show a significant increase in Minor Physical Anomalies compared with Normal children. The inter correlation of Minor Physical Anomalies with various domains of soft signs showed positivity for overflow and timed movements, especially for sibling group in lower middle and upper lower group. There is no significant difference between males and females in both sibling group and normal children in Neurological Soft Signs and Minor Physical Anomalies

    Monitoring cortical excitability during repetitive transcranial magnetic stimulation in children with ADHD: a single-blind, sham-controlled TMS-EEG study

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    Background: Repetitive transcranial magnetic stimulation (rTMS) allows non-invasive stimulation of the human brain. However, no suitable marker has yet been established to monitor the immediate rTMS effects on cortical areas in children. Objective: TMS-evoked EEG potentials (TEPs) could present a well-suited marker for real-time monitoring. Monitoring is particularly important in children where only few data about rTMS effects and safety are currently available. Methods: In a single-blind sham-controlled study, twenty-five school-aged children with ADHD received subthreshold 1 Hz-rTMS to the primary motor cortex. The TMS-evoked N100 was measured by 64-channel-EEG pre, during and post rTMS, and compared to sham stimulation as an intraindividual control condition. Results: TMS-evoked N100 amplitude decreased during 1 Hz-rTMS and, at the group level, reached a stable plateau after approximately 500 pulses. N100 amplitude to supra-threshold single pulses post rTMS confirmed the amplitude reduction in comparison to the pre-rTMS level while sham stimulation had no influence. EEG source analysis indicated that the TMS-evoked N100 change reflected rTMS effects in the stimulated motor cortex. Amplitude changes in TMS-evoked N100 and MEPs (pre versus post 1 Hz-rTMS) correlated significantly, but this correlation was also found for pre versus post sham stimulation. Conclusion: The TMS-evoked N100 represents a promising candidate marker to monitor rTMS effects on cortical excitability in children with ADHD. TMS-evoked N100 can be employed to monitor real-time effects of TMS for subthreshold intensities. Though TMS-evoked N100 was a more sensitive parameter for rTMS-specific changes than MEPs in our sample, further studies are necessary to demonstrate whether clinical rTMS effects can be predicted from rTMS-induced changes in TMS-evoked N100 amplitude and to clarify the relationship between rTMS-induced changes in TMS-evoked N100 and MEP amplitudes. The TMS-evoked N100 amplitude reduction after 1 Hz-rTMS could either reflect a globally decreased cortical response to the TMS pulse or a specific decrease in inhibition

    Neurofeedback effect on perceptual-motor skills of children with ADHD

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    Objectives: This study investigates the impact of neurofeedback on perceptual-motor skills of 5 to 12 years old children with Attention Deficit Hyperactive Disorder (ADHD). Methods: In this clinical study, 40 children between the ages of 5-12 years, who were patients of the Tavanesh Clinic and diagnosed with ADHD, were randomly chosen and divided into two groups of control and test. 20-neurofeedback intervention sessions were performed. The tools utilized in this study included Bruninks-Oseretsky Test of Motor Proficiency and Child behavior checklist (CBCL) survey questionnaire. For evaluation after the intervention, Bruninks-Oseretsky Test of Motor Proficiency scale for children, along with CBCL questionnaire surveys were asked to fill up by the participants' mothers. Results: After the intervention, the analysis of the scores in all perceptual-motor skills showed significant differences in both groups, but no significant difference was observed in the subtest of strength. The CBCL survey questionnaire revealed that the average scores on attention disorder, aggression, lack of attention and hyperactivity, externalizing and general problems in the test group is significantly less than that of the control group. However, in the confrontational behavior (internalization), there was no statistically significant difference between the test and control groups. There was a correlation between the change of motor skills and change of behavioral patterns in ADHD children. Discussion: Neurofeedback intervention can have positive effects on improving the perceptualmotor skills of children with ADHD
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