Current and emerging strategies for treatment of childhood dystonia

Clinician Knowledge, Confidence, and Practice Patterns Defining, Identifying, and Quantifying Dystonia in Children: A Cross-Sectional Survey Study

A survey was completed by 183 clinicians at a pediatric hospital to investigate knowledge, confidence, and practice patterns defining, identifying, and quantifying dystonia in children. The definition of dystonia was correctly identified by 86% of participants. While 88% reported identifying dystonia, only 42% of physicians and therapists reported quantifying dystonia. A weak, significant correlation, rs =.339, p ≤ .001, was found between years of pediatric experience and confidence identifying dystonia. Clinician reported higher confidence levels identifying and quantifying dystonia if they perform a neurological exam. Clinical training initiatives are needed to improve standardization and build confidence in defining, identifying, and quantifying dystonia.

Stereotactic Awake Basal Ganglia Electrophysiological Recording and Stimulation (SABERS): A Novel Staged Procedure for Personalized Targeting of Deep Brain Stimulation in Pediatric Movement and Neuropsychiatric Disorders

Selection of targets for deep brain stimulation (DBS) has been based on clinical experience, but inconsistent and unpredictable outcomes have limited its use in patients with heterogeneous or rare disorders. In this large case series, a novel staged procedure for neurophysiological assessment from 8 to 12 temporary depth electrodes is used to select targets for neuromodulation that are tailored to each patient's functional needs. Thirty children and young adults underwent deep brain stimulation target evaluation with the new procedure: Stereotactic Awake Basal ganglia Electrophysiological Recording and Stimulation (SABERS). Testing is performed in an inpatient neuromodulation monitoring unit over 5-7 days, and results guide the decision to proceed and the choice of targets for permanent deep brain stimulation implantation. Results were evaluated 3-6 months postoperatively with the Burke-Fahn-Marsden Dystonia Rating Scale and the Barry-Albright Dystonia Scale. Stereotactic Awake Basal ganglia Electrophysiological Recording and Stimulation testing allowed modulation to be tailored to specific neurologic deficits in a heterogeneous population, including subjects with primary dystonia, secondary dystonia, and Tourette syndrome. All but one subject were implanted with 4 permanent deep brain stimulation leads. Results showed significant improvement on both scales at postoperative follow-up. No significant adverse events occurred. Use of the Stereotactic Awake Basal ganglia Electrophysiological Recording and Stimulation protocol with evaluation in the neuromodulation monitoring unit is feasible and results in significant patient benefit compared with previously published results in these populations. This new technique supports a significant expansion of functional neurosurgery to predict effective stimulation targets in a wide range of disorders of brain function, including those for which the optimal target is not yet known.

Content Validation of the Movement Disorder-Childhood Rating Scale (MD-CRS) for Dyskinetic Cerebral Palsy

BACKGROUND

Dyskinetic cerebral palsy (DCP), a lifelong neurological disorder beginning in early childhood, manifests with hyperkinetic movements and dystonia. The Movement Disorder-Childhood Rating Scale (MD-CRS) is a clinician-reported outcome measure assessing the intensity of movement disorders and their effect on daily life in pediatric patients. Content validity of clinical outcome assessments is key to accurately capturing patient perspective. Evidence demonstrating content validity of the MD-CRS in patients with DCP is needed. This study captures input from patients with DCP and their caregivers regarding the content validity of the MD-CRS.

METHODS

This qualitative, noninterventional, cross-sectional study included interviews with children/adolescents (aged six to 18 years) with DCP and caregivers of children with DCP. Participants were asked to describe body regions and daily functions affected by DCP. Caregivers also reviewed MD-CRS Part I to evaluate the relevance of the items and corresponding response options. Descriptions of DCP were coded and mapped to MD-CRS items and response options. Caregiver feedback on MD-CRS Part I was analyzed using inductive content analysis.

RESULTS

Eight patients and 12 caregivers were interviewed. Participants confirmed that the body regions and activities listed in the MD-CRS were affected by DCP and that involuntary movements interfered with all motor, oral/verbal, self-care, and video protocol activities. Caregivers endorsed the response options for 12 of 15 items in MD-CRS Part I and suggested clarifications for others.

CONCLUSIONS

Participants confirmed that affected body regions and activities listed in the MD-CRS were relevant to their experience with DCP, demonstrating the content validity of this tool in children/adolescents with DCP.

Combined effect of orthotic intervention and conventional exercise training on balance and gait performance in cerebral palsy: a randomized controlled trial

Background

This study aimed to examine the combined effect of orthotic intervention and conventional therapeutic exercise training on balance and gait performance in children with cerebral palsy. This study was a randomized control trial. Forty children with dyskinetic cerebral palsy of both genders with ages ranged from 12 to 16 years were included. Participants in the control and study groups received a conventional therapeutic exercise training program for two 2 h ours per session. The treatment program was conducted three sessions per week, for twelve 12 successive weeks. Children in the study group additionally wore TheraTogs orthotic undergarment with the strapping system. Pediatric Balance Scale score and postural stability indices (overall, anteroposterior , and mediolateral) evaluated by the Biodex Balance System were assessed (in both groups) at baseline and after 12 weeks of treatment. The changes of step length, gait cycle time, cadence, and velocity were also measured by an electronic walkway.

Results

Children in the study group showed significant improvements in the scores of all the measured variables post-treatment compared to the control group (P < 0.05). The P -values for overall, anteroposterior and mediolateral postural stability indices were 0.011, 0.014, and 0.021, respectively. The P -values for Pediatric Balance Scale score, step length, gait cycle time, cadence, and velocity were 0.001, 0.023, 0.041, 0.011, and 0.013 respectively.

Conclusions

Conventional therapeutic exercise training combined with orthotic intervention were more effective in improving balance and gait performance in children with dyskinetic cerebral palsy.

Trial registration

The ClinicalTrial.gov PRS (NCT04990193).

Registered 4 August 2021 - Retrospectively registered.

Childhood dystonic reactions in the middle Black Sea region

Acute dystonic reactions are a worrying reason for presentation to the pediatric emergency department and the pediatric neurology clinic in childhood. It must be diagnosed and treated quickly. The aim of this study was to examine the clinical presentations, etiological factors, and prognosis of patients presenting to our regional tertiary pediatric neurology clinic with a diagnosis of acute dystonic reactions in children.Nine pediatric patients who were treated for acute dystonic reactions between May, 2018 and May, 2020 and had adequate follow-up were included in the study. Medical record data were reviewed age, gender, etiology, features of family, treatment, and results.Three of the patients were female and 6 were male. Their average age was 11 years (4-17). All patients were evaluated as a drug-induced acute dystonic reaction. Of the 9 patients, 5 were due to metoclopramide, 3 were due to risperidone, and 1 was due to aripiprazole. It was learned that a similar situation against other drugs developed in the family history of 3 patients. As a treatment, all of them were intramuscularly applied biperiden suitable for their weight and 30 minutes dramatic improvement was observed. Additional dose had to be administered in only 1 case. All cases were discharged for 24 hours. No problem was observed in their follow-up.Drug-induced acute dystonic reaction can be diagnosed and has a clinical picture that completely resolves when effective treatment is applied. However, it should not be forgotten that it can reach life-threatening dimensions clinically.

Efficacy of axial TheraTogs on gait pattern in children with dyskinetic cerebral palsy: a randomized controlled trial

Background

TheraTogs promotes proprioceptive sense of a child with cerebral palsy and improves abnormal muscle tone, posture alignment, balance, and gait. Therefore, the aim of this study was to investigate the efficacy of TheraTogs orthotic undergarment on gait pattern in children with dyskinetic cerebral palsy. Thirty children with dyskinetic cerebral palsy were selected for this randomized controlled study. They were randomly assigned to (1) an experimental group that received TheraTogs orthotic undergarment (12 h/day, 3 days/week) plus traditional physical therapy for 3 successive months and (2) a control group that received only traditional physical therapy program for the same time period. Gait parameters were measured at baseline and after 3 months of intervention using Pro-Reflex motion analysis.

Results

Children in both groups showed significant improvements in the gait parameters (P < 0.05), with significantly greater improvements in the experimental group than in the control group.

Conclusions

The use of TheraTogs may have a positive effect to improve gait pattern in children with dyskinetic cerebral palsy.

Trial registration

This trial was registered in the ClinicalTrial.gov PRS (NCT03037697).

Can spatial filtering separate voluntary and involuntary components in children with dyskinetic cerebral palsy?

The design of myocontrolled devices faces particular challenges in children with dyskinetic cerebral palsy because the electromyographic signal for control contains both voluntary and involuntary components. We hypothesized that voluntary and involuntary components of movements would be uncorrelated and thus detectable as different synergistic patterns of muscle activity, and that removal of the involuntary components would improve online EMG-based control. Therefore, we performed a synergy-based decomposition of EMG-guided movements, and evaluated which components were most controllable using a Fitts' Law task. Similarly, we also tested which muscles were most controllable. We then tested whether removing the uncontrollable components or muscles improved overall function in terms of movement time, success rate, and throughput. We found that removal of less controllable components or muscles did not improve EMG control performance, and in many cases worsened performance. These results suggest that abnormal movement in dyskinetic CP is consistent with a pervasive distortion of voluntary movement rather than a superposition of separable voluntary and involuntary components of movement.

Deep brain stimulation for cerebral palsy: where are we now?

Cerebral palsy (CP) is a complex disorder and children frequently have multiple impairments. Dystonia is a particularly frustrating impairment that interferes with rehabilitation and function and is difficult to treat. Of the available treatments, deep brain stimulation (DBS) has emerged as an option with the potential for large effect size in a subgroup of children. While brain stimulation has been used in CP for more than 40 years, modern devices and targeting methods are improving both the safety and efficacy of the procedure. Successful use of DBS depends on appropriate selection of patients, identification of effective neuroanatomical targets in each patient, careful neurosurgical procedure, and detailed follow-up evaluation and programming. The use of functional neurosurgery for neuromodulation in CP remains a technology in its infancy, but improving experience and knowledge are likely to make this one of the safest and most effective interventions for children with moderate-to-severe motor disorders. This review summarizes the current procedures for patient and target selection, and surgical implantation of DBS electrodes for CP. The history of DBS and future directions when used in secondary dystonia are also examined. WHAT THIS PAPER ADDS: Selection of candidates for deep brain stimulation (DBS) requires understanding of dystonia in cerebral palsy . DBS could become a first-line treatment option in some children.

EMG-based vibro-tactile biofeedback training: effective learning accelerator for children and adolescents with dystonia? A pilot crossover trial

Background

This study is aimed at better understanding the role of a wearable and silent ElectroMyoGraphy-based biofeedback on motor learning in children and adolescents with primary and secondary dystonia.

Methods

A crossover study with a wash-out period of at least 1 week was designed; the device provides the patient with a vibration proportional to the activation of an impaired target muscle. The protocol consisted of two 5-day blocks during which subjects were trained and tested on a figure-8 writing task: their performances (at different levels of difficulty) were evaluated in terms of both kinematics and muscular activations on day 1 and day 5, while the other 3 days were purely used as training sessions. The training was performed with and without using the biofeedback device: the week of use was randomized. Data were collected on 14 subjects with primary and secondary (acquired) dystonia (age: 6–19 years).

Results

Results comparing kinematic-based and EMG-based outcome measures pre- and post-training showed learning due to practice for both subjects with primary and secondary dystonia. On top of said learning, an improvement in terms of inter-joint coordination and muscular pattern functionality was recorded only for secondary dystonia subjects, when trained with the aid of the EMG-based biofeedback device.

Conclusions

Our results support the hypothesis that children and adolescents with primary dystonia in which there is intact sensory processing do not benefit from feedback augmentation, whereas children with secondary dystonia, in which sensory deficits are often present, exhibit a higher learning capacity when augmented movement-related sensory information is provided. This study represents a fundamental investigation to address the scarcity of noninvasive therapeutic interventions for young subjects with dystonia.

A Model to Estimate the Optimal Layout for Assistive Communication Touchscreen Devices in Children With Dyskinetic Cerebral Palsy

Excess involuntary movements and slowness of movement in children with dyskinetic cerebral palsy often result in the inability to properly interact with augmentative and alternative communication (AAC) devices. This significantly limits communication. It is, therefore, essential to know how to adjust the device layout in order to maximize each child's rate of communication. The aim of this paper was to develop a mathematical model to estimate the information rate in children with dyskinetic cerebral palsy and to determine the optimal AAC layout for a touchscreen tablet that results in enhanced speed of communication. The model predicts information rate based on button size, number, spacing between buttons, and the probability of making an error or missing target buttons. Estimation of the information rate confirmed our hypothesis of lower channel capacity in children with dyskinetic cerebral palsy compared with age-matched healthy children. Information rate increased when the AAC layout was customized based on the optimal parameters predicted by the model. In conclusion, this paper quantifies the effect of motor impairments on communication with assistive communication devices and shows that communication performance can be improved by optimally matching the parameters of the AAC touchscreen device to the abilities of the child.

Upper-limb contracture development in children with cerebral palsy: a population-based study

AIM

The aim of this study was to investigate the longitudinal development of passive range of motion (ROM) in the upper limbs in a population-based sample of children with cerebral palsy (CP), and to investigate which children are more likely to develop contractures related to functional level, CP subtype, and age.

METHOD

Registry data of annual passive ROM measurements of the upper limbs from 771 children with CP (417 males, 354 females; mean age 11y 8mo, [SD 5mo] range 1-18y) were analysed. Mixed models were used to investigate at what age decreased passive ROM occurs. Odds ratios were calculated to compare risks and logistic regression analysis was used to predict contracture development.

RESULTS

Thirty-four per cent of the children had developed contractures. Among these children, decreased passive ROM was significant at a mean age of 4 years for wrist extension and 7 years for shoulder flexion, elbow extension, and supination. Children at Manual Ability Classification System (MACS) level V had a 17-times greater risk of contractures than children at MACS level I.

INTERPRETATION

One-third of the children in the total population developed upper-limb contractures while passive ROM decreased with age. MACS level was the strongest predictor of contracture development.

WHAT THIS PAPER ADDS

In a population-based sample of 771 children with cerebral palsy, 34% developed an upper-limb contracture. Contracture development started at preschool age. The first affected movements were wrist extension and supination. Passive range of motion decreased with age. High Manual Ability Classification System level was the most important predictor of contractures.

Why orthotic devices could be of help in the management of Movement Disorders in the young

Background

Movement Disorders (MD) are a class of disease that impair the daily activities of patients, conditioning their sensorimotor, cognitive and behavioural capabilities. Nowadays, the general management of patients with MD is based on rehabilitation, pharmacological treatments, surgery, and traditional splints. Although some attempts have been made to devise specific orthoses for the rehabilitation of patients affected by MD, especially the younger ones, those devices have received limited attention.

Main body

This paper will principally discuss the case of upper limb rehabilitation in Childhood Dyskinesia (CD), a complex motor disease that affects paediatric patients. Through a critical review of the present solutions and a discussion about the neurophysiological characteristics of the disease, the study will lead to the formulation of desirable features of a possible new upper-limb orthosis.

Conclusions

Design principles will be derived to provide specialised orthoses for the dynamic control of posture and the stabilisation of voluntary movements: those include using biomechanical actions and enhanced proprioception to support the sensorimotor rehabilitation of the children affected by CD. A similar approach could be advantageously applied in other MD-related conditions, especially with hyperkinetic and/or hypertonic traits.

Pediatric Deep Brain Stimulation Using Awake Recording and Stimulation for Target Selection in an Inpatient Neuromodulation Monitoring Unit

Deep brain stimulation (DBS) for secondary (acquired, combined) dystonia does not reach the high degree of efficacy achieved in primary (genetic, isolated) dystonia. We hypothesize that this may be due to variability in the underlying injury, so that different children may require placement of electrodes in different regions of basal ganglia and thalamus. We describe a new targeting procedure in which temporary depth electrodes are placed at multiple possible targets in basal ganglia and thalamus, and probing for efficacy is performed using test stimulation and recording while children remain for one week in an inpatient Neuromodulation Monitoring Unit (NMU). Nine Children with severe secondary dystonia underwent the NMU targeting procedure. In all cases, 4 electrodes were implanted. We compared the results to 6 children who had previously had 4 electrodes implanted using standard intraoperative microelectrode targeting techniques. Results showed a significant benefit, with 80% of children with NMU targeting achieving greater than 5-point improvement on the Burke–Fahn–Marsden Dystonia Rating Scale (BFMDRS), compared with 50% of children using intraoperative targeting. NMU targeting improved BFMDRS by an average of 17.1 whereas intraoperative targeting improved by an average of 10.3. These preliminary results support the use of test stimulation and recording in a Neuromodulation Monitoring Unit (NMU) as a new technique with the potential to improve outcomes following DBS in children with secondary (acquired) dystonia. A larger sample size will be needed to confirm these results.

Outcome measures for children with movement disorders

The huge contribution of advances in the pediatric neurosciences, improvements in clinical practice, and new therapeutic options, has led to the development of new models of treatment and rehabilitation for dystonia in the last decade. It is now generally agreed that a multidimensional therapeutic approach is needed for children with motor disorders, whose motor function-conceived as a complex perceptive, motor and cognitive process - is impaired at a crucial time in their development, with a fall out on how their various adaptive functions evolve. Neurophysiological studies, modern neuroimaging techniques, and advances in cognitive psychology have all contributed to improving our understanding of the potential effects of treatments in early age - not only on the symptoms, but also on plasticity processes and neuronal reorganization. The International Classification of Functioning, Disability and Health (ICF) promoted by the WHO, and the diffusion of family-centered models of healthcare have underscored the importance of the ecological perspective with a view to providing effective therapies and a satisfactory quality of life for dystonic children and their families. The advances made in this area have made it necessary to study and develope more appropriate treatment outcome measures. In the light of these aspects, there is still not enough literature on the generally-accepted, exhaustive dystonia assessment tools. Given these limits, it might be useful to discuss the strengths and weaknesses of the main tools currently used in this setting.

Management of Pediatric Movement Disorders: Present and Future

Management of movement disorders in children is an evolving field. This article outlines the major categories of treatment options for pediatric movement disorders and general guidelines for their use. We review the evidence for existing therapies, which continue to lack large-scale controlled trials to guide treatment decisions. The field continues to rely on extrapolations from adult studies and lower quality evidence such as case reports and case series to guide treatment guidelines and consensus statements. Developments in new pharmaceuticals for rare diseases have begun to provide hope for those cases in which a genetic diagnosis can be made. Advances in surgical therapies such as deep brain stimulation as well as new modes of treatment such as gene therapy, epigenetic modulation, and stem cell therapy hold promise for improving outcomes in both primary and secondary causes of movement disorders. There is a critical need for larger, multicenter, controlled clinical trials to fully evaluate treatments for pediatric movement disorders.

High motor variability in DYT1 dystonia is associated with impaired visuomotor adaptation

For the healthy motor control system, an essential regulatory role is maintaining the equilibrium between keeping unwanted motor variability in check whilst allowing informative elements of motor variability. Kinematic studies in children with generalised dystonia (due to mixed aetiologies) show that movements are characterised by increased motor variability. In this study, the mechanisms by which high motor variability may influence movement generation in dystonia were investigated. Reaching movements in the symptomatic arm of 10 patients with DYT1 dystonia and 12 age-matched controls were captured using a robotic manipulandum and features of motor variability were extracted. Given that task-relevant variability and sensorimotor adaptation are related in health, markers of variability were then examined for any co-variance with performance indicators during an error-based learning visuomotor adaptation task. First, we confirmed that motor variability on a trial-by-trial basis was selectively increased in the homogenous and prototypical dystonic disorder DYT1 dystonia. Second, high baseline variability predicted poor performance in the subsequent visuomotor adaptation task offering insight into the rules which appear to govern dystonic motor control. The potential mechanisms behind increased motor variability and its corresponding implications for the rehabilitation of patients with DYT1 dystonia are highlighted.

The integration of probabilistic information during sensorimotor estimation is unimpaired in children with Cerebral Palsy

Background

It is important to understand the motor deficits of children with Cerebral Palsy (CP). Our understanding of this motor disorder can be enriched by computational models of motor control. One crucial stage in generating movement involves combining uncertain information from different sources, and deficits in this process could contribute to reduced motor function in children with CP. Healthy adults can integrate previously-learned information (prior) with incoming sensory information (likelihood) in a close-to-optimal way when estimating object location, consistent with the use of Bayesian statistics. However, there are few studies investigating how children with CP perform sensorimotor integration. We compare sensorimotor estimation in children with CP and age-matched controls using a model-based analysis to understand the process.

Methods and findings

We examined Bayesian sensorimotor integration in children with CP, aged between 5 and 12 years old, with Gross Motor Function Classification System (GMFCS) levels 1–3 and compared their estimation behavior with age-matched typically-developing (TD) children. We used a simple sensorimotor estimation task which requires participants to combine probabilistic information from different sources: a likelihood distribution (current sensory information) with a prior distribution (learned target information). In order to examine sensorimotor integration, we quantified how participants weighed statistical information from the two sources (prior and likelihood) and compared this to the statistical optimal weighting. We found that the weighing of statistical information in children with CP was as statistically efficient as that of TD children.

Conclusions

We conclude that Bayesian sensorimotor integration is not impaired in children with CP and therefore, does not contribute to their motor deficits. Future research has the potential to enrich our understanding of motor disorders by investigating the stages of motor processing set out by computational models. Therapeutic interventions should exploit the ability of children with CP to use statistical information.

Scaled Vibratory Feedback Can Bias Muscle Use in Children With Dystonia During a Redundant, 1-Dimensional Myocontrol Task

Vibratory feedback can be a useful tool for rehabilitation. We examined its use in children with dystonia to understand how it affects muscle activity in a population that does not respond well to standard rehabilitation. We predicted scaled vibration (ie, vibration that was directly or inversely proportional to muscle activity) would increase use of the vibrated muscle because of task-relevant sensory information, whereas nonscaled vibration would not change muscle use. The study was conducted on 11 subjects with dystonia and 14 controls. Each subject underwent 4 different types of vibration on the more dystonic biceps muscle (or nondominant arm in controls) in a 1-dimensional, bimanual myocontrol task. Our results showed that only scaled vibratory feedback could bias muscle use without changing overall performance in children with dystonia. We believe there may be a role in rehabilitation for scaled vibratory feedback to retrain abnormal muscle patterns.

The International Classification of Functioning (ICF) to evaluate deep brain stimulation neuromodulation in childhood dystonia-hyperkinesia informs future clinical & research priorities in a multidisciplinary model of care

The multidisciplinary team (MDT) approach illustrates how motor classification systems, assessments and outcome measures currently available have been applied to a national cohort of children and young people with dystonia and other hyperkinetic movement disorders (HMD) particularly with a focus on dyskinetic cerebral palsy (CP). The paper is divided in 3 sections. Firstly, we describe the service model adopted by the Complex Motor Disorders Service (CMDS) at Evelina London Children's Hospital and King's College Hospital (ELCH-KCH) for deep brain stimulation. We describe lessons learnt from available dystonia studies and discuss/propose ways to measure DBS and other dystonia-related intervention outcomes. We aim to report on current available functional outcome measures as well as some impairment-based assessments that can encourage and generate discussion among movement disorders specialists of different backgrounds regarding choice of the most important areas to be measured after DBS and other interventions for dystonia management. Finally, some recommendations for multi-centre collaboration in regards to functional clinical outcomes and research methodologies for dystonia-related interventions are proposed.

The Burke-Fahn-Marsden Dystonia Rating Scale is Age-Dependent in Healthy Children

Background

The Burke-Fahn-Marsden Dystonia Rating Scale is a universally applied instrument for the quantitative assessment of dystonia in both children and adults. However, immature movements by healthy young children may also show "dystonic characteristics" as a consequence of physiologically incomplete brain maturation. This could implicate that Burke-Fahn-Marsden scale scores are confounded by pediatric age.

Objective

In healthy young children, we aimed to determine whether physiologically immature movements and postures can induce an age-related effect on Burke-Fahn-Marsden movement and disability scale scores.

Methods

Nine assessors specializied in movement disorders (3 adult neurologists, 3 pediatric neurologists, and 3 MD/PhD students) independently scored the Burke-Fahn-Marsden movement scale in 52 healthy children (4-16 years of age; 2 boys and 2 girls per year of age). Independent of that, parents scored their children's functional motor development according to the Burke-Fahn-Marsden disability scale in another 52 healthy children (4-16 years of age; 2 boys and 2 girls per year of age). By regression analysis, we determined the association between Burke-Fahn-Marsden movement and disability scales outcomes and pediatric age.

Results

In healthy children, assessment of physiologically immature motor performances by the Burke-Fahn-Marsden movement and disability scales showed an association between the outcomes of both scales and age (until 16 years and 12 years of age, β = -0.72 and β = -0.60, for Burke-Fahn-Marsden movement and disability scale, respectively [both P < 0.001]).

Conclusions

The Burke-Fahn-Marsden movement and disability scales are influenced by the age of the child. For accurate interpretation of longitudinal Burke-Fahn-Marsden Dystonia Rating Scale scores in young dystonic children, consideration of pediatric age-relatedness appears advisory.

Post stroke hemi-dystonia in children: a neglected area of research

BACKGROUND

Childhood arterial ischemic stroke (CAIS) is increasingly recognized as an important cause of significant long-term morbidity in the pediatric population. Post stroke movement disorders, above all hemi-dystonias, are much more common in children after stroke compared to adults. However, research in this field is largely lacking. By highlighting some important knowledge gaps, we aim to encourage future collaborative research projects in this particular field.

FINDINGS

Post stroke-dystonia seems to be much more common among children than adults. However, no reliable epidemiological data of post-stroke movement disorders in childhood are available, and differentiation between spasticity and dystonia can be challenging. Pharmacotherapy for dystonia is limited by lack of effect, especially in the long-term treatment. The pathophysiology of dystonia is complex and incompletely understood. Recent findings from functional imaging studies suggest that dystonia does not result from a single lesion but rather network dysfunctions and abnormalities in functional connectivity. However, very few patients with post stroke dystonia have been studied, and it is not clear to what extent pathophysiology of primary and post stroke ischemia shares common characteristics on network level. In general, progress in understanding the nature of childhood dystonia lags far behind adult onset CNS diseases.

CONCLUSIONS

Dystonia after CAIS is a common yet insufficiently understood and poorly studied clinical challenge. Studies to improve our understanding of the underlying pathophysiology and consequently the development of instruments for early prediction as well as targeted treatment of dystonia should become a high priority in collaborative childhood stroke research.