Interventional studies in childhood dystonia do not address the concerns of children and their carers

Neurosurgical management of elevated tone in childhood: interventions, indications and uncertainties

Elevated tone (hypertonia) is a common problem in children with physical disabilities. Medications intended to reduce tone often have limited efficacy, with use further limited by a significant side effect profile. Consequently, there has been growing interest in the application of Neurosurgical Interventions for the Management of Posture and Tone (NIMPTs). Three main procedures are now commonly used: selective dorsal rhizotomy (SDR), intrathecal baclofen (ITB) and deep brain stimulation (DBS). This review compares these interventions, along with discussion on the potential role of lesioning surgery. These interventions variably target spasticity and dystonia, acting at different points in the distributed motor network. SDR, an intervention for reducing spasticity, is most widely used in carefully selected ambulant children with cerebral palsy. ITB is more commonly used for children with more severe disability, typically non-ambulant, and can improve both dystonia and spasticity. DBS is an intervention which may improve dystonia. In children with certain forms of genetic dystonia DBS may dramatically improve dystonia. For other causes of dystonia, and in particular dystonia due to acquired brain injury, improvements following surgery are more modest and variable. These three interventions vary in terms of their side-effect profile and reversibility. There are currently populations of children for who it is unclear which intervention should be considered (SDR vs ITB, or ITB vs DBS). Concerns have been raised as to the equity of access to NIMPTs for children across the UK, and whether the number of surgeries performed each year meets the clinical need.

Long-Term Follow-Up of Pediatric Patients with Dyskinetic Cerebral Palsy and Deep Brain Stimulation

BACKGROUND

Deep brain stimulation (DBS) has been increasingly used in the management of dyskinetic cerebral palsy (DCP). Data on long-term effects and the safety profile are rare.

OBJECTIVES

We assessed the efficacy and safety of pallidal DBS in pediatric patients with DCP.

METHODS

The STIM-CP trial was a prospective, single-arm, multicenter study in which patients from the parental trial agreed to be followed-up for up to 36 months. Assessments included motor and non-motor domains.

RESULTS

Of the 16 patients included initially, 14 (mean inclusion age 14 years) were assessed. There was a significant change in the (blinded) ratings of the total Dyskinesia Impairment Scale at 36 months. Twelve serious adverse events (possibly) related to treatment were documented.

CONCLUSION

DBS significantly improved dyskinesia, but other outcome parameters did not change significantly. Investigations of larger homogeneous cohorts are needed to further ascertain the impact of DBS and guide treatment decisions in DCP. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Metabolic patterns in brain 18F-fluorodeoxyglucose PET relate to aetiology in paediatric dystonia

There is a lack of imaging markers revealing the functional characteristics of different brain regions in paediatric dystonia. In this observational study, we assessed the utility of [18F]2-fluoro-2-deoxy-D-glucose (FDG)-PET in understanding dystonia pathophysiology by revealing specific resting awake brain glucose metabolism patterns in different childhood dystonia subgroups. PET scans from 267 children with dystonia being evaluated for possible deep brain stimulation surgery between September 2007 and February 2018 at Evelina London Children's Hospital (ELCH), UK, were examined. Scans without gross anatomical abnormality (e.g. large cysts, significant ventriculomegaly; n = 240) were analysed with Statistical Parametric Mapping (SPM12). Glucose metabolism patterns were examined in the 144/240 (60%) cases with the 10 commonest childhood-onset dystonias, focusing on nine anatomical regions. A group of 39 adult controls was used for comparisons. The genetic dystonias were associated with the following genes: TOR1A, THAP1, SGCE, KMT2B, HPRT1 (Lesch Nyhan disease), PANK2 and GCDH (Glutaric Aciduria type 1). The acquired cerebral palsy (CP) cases were divided into those related to prematurity (CP-Preterm), neonatal jaundice/kernicterus (CP-Kernicterus) and hypoxic-ischaemic encephalopathy (CP-Term). Each dystonia subgroup had distinct patterns of altered FDG-PET uptake. Focal glucose hypometabolism of the pallidi, putamina or both, was the commonest finding, except in PANK2, where basal ganglia metabolism appeared normal. HPRT1 uniquely showed glucose hypometabolism across all nine cerebral regions. Temporal lobe glucose hypometabolism was found in KMT2B, HPRT1 and CP-Kernicterus. Frontal lobe hypometabolism was found in SGCE, HPRT1 and PANK2. Thalamic and brainstem hypometabolism were seen only in HPRT1, CP-Preterm and CP-term dystonia cases. The combination of frontal and parietal lobe hypermetabolism was uniquely found in CP-term cases. PANK2 cases showed a distinct combination of parietal hypermetabolism with cerebellar hypometabolism but intact putaminal-pallidal glucose metabolism. HPRT1, PANK2, CP-kernicterus and CP-preterm cases had cerebellar and insula glucose hypometabolism as well as parietal glucose hypermetabolism. The study findings offer insights into the pathophysiology of dystonia and support the network theory for dystonia pathogenesis. 'Signature' patterns for each dystonia subgroup could be a useful biomarker to guide differential diagnosis and inform personalized management strategies.

Probabilistic mapping of deep brain stimulation in childhood dystonia

OBJECTIVES

In adults with dystonia Probabilistic Stimulation Mapping (PSM) has identified putative "sweet spots" for stimulation. We aimed to apply PSM to a cohort of Children and Young People (CYP) following DBS surgery.

METHODS

Pre-operative MRI and post-operative CT images were co-registered for 52 CYP undergoing bilateral pallidal DBS (n = 31 genetic/idiopathic dystonia, and n = 21 Cerebral Palsy (CP)). DBS electrodes (n = 104) were automatically detected, and Volumes of Tissue Activation (VTA) derived from individual patient stimulation settings. VTAs were normalised to the MNI105 space, weighted by percentage improvement in Burke-Fahn-Marsden Dystonia Rating scale (BFMDRS) at one-year post surgery and mean improvement was calculated for each voxel.

RESULTS

For the genetic/idiopathic dystonia group, BFMDRS improvement was associated with stimulation across a broad volume of the GPi. A spatial clustering of the upper 25th percentile of voxels corresponded with a more delineated volume within the posterior ventrolateral GPi. The MNI coordinates of the centroid of this volume (X = -23.0, Y = -10.5 and Z = -3.5) were posterior and superior to the typical target for electrode placement. Volume of VTA overlap with a previously published "sweet spots" correlated with improvement following surgery. In contrast, there was minimal BFMDRS improvement for the CP group, no spatial clustering of efficacious clusters and a correlation between established "sweet spots" could not be established.

CONCLUSIONS

PSM in CYP with genetic/idiopathic dystonia suggests the presence of a "sweet spot" for electrode placement within the GPi, consistent with previous studies. Further work is required to identify and validate putative "sweet spots" across different cohorts of patients.

Caregiver perspectives of managing chronic pain in children and adolescents with dyskinetic and mixed dyskinetic/spastic CP with communication limitations

PURPOSE

Caregivers provide unique insights into managing chronic pain in children and adolescents with dyskinetic and mixed dyskinetic/spastic cerebral palsy with communication limitations. This study explored the personal challenges caregivers face in supporting their child's everyday pain management, including barriers and facilitators to effective chronic pain management.

METHODS

Semi-structured interviews were undertaken with ten caregivers (all mothers) of children with either dyskinetic or mixed dyskinetic/spastic cerebral palsy. All children had chronic pain (> 3 months), were aged from 5 to 15 years, had significant functional limitations, and had either limited or no capacity to self-report their pain. Interpretative phenomenological analysis was used to explore caregivers' subjective experiences of managing their child's chronic pain within family, school, and healthcare contexts.

RESULTS

Five superordinate themes emerged: 1. the continual challenge of problem solving pain and dyskinesia; 2. the pursuit of a solution; 3. unfulfilled preferences within pain management; 4. all-encompassing effects on families; and 5. the ongoing impacts of pain and dyskinesia with age.

CONCLUSION

There is a need for structured pain education and resources targeted towards caregivers and support workers that account for the complex overlay of dyskinesia. There is a further need to ensure caregiver preferences for non-pharmacological pain treatments are met within family-centred care models.

The Dyskinetic Cerebral Palsy Functional Impact Scale: development and validation of a new tool

AIM

To outline the development and examine the content and construct validity of a new tool, the Dyskinetic Cerebral Palsy Functional Impact Scale (D-FIS), which measures the impact of dyskinesia on everyday activities in children with cerebral palsy (CP).

METHOD

D-FIS content was informed by a systematic review of dyskinesia outcome measures, in collaboration with children with dyskinetic CP, parents, caregivers, and expert clinicians. The D-FIS uses parent proxy to rate impact of dyskinesia on everyday activities. Construct validity was determined by examining internal consistency; known groups validity with the Gross Motor Function Classification System (GMFCS), Manual Ability Classification System (MACS), Communication Function Classification System (CFCS), and Eating and Drinking Ability Classification System (EDACS); and convergent validity with the Barry-Albright Dystonia Scale (BADS).

RESULTS

Fifty-seven parents of children (29 males, 28 females, mean [SD] age 11y 8mo [4y 4mo], range 2y 6mo-18y) completed the D-FIS. Correlation between D-FIS and GMFCS was r=0.86 (95% confidence interval [CI]: 0.77-0.91, p<0.001); MACS r=0.84 (95% CI: 0.73-0.90, p<0.001); CFCS r=0.80 (95% CI: 0.67-0.88, p<0.001); and EDACS r=0.78 (95% CI: 0.66-0.87). Correlation between D-FIS and BADS was r=0.77 (95% CI: 0.64-0.86, p<0.001). Cronbach's alpha was 0.96.

INTERPRETATION

The D-FIS demonstrates good construct validity and high internal consistency. The D-FIS will be useful for identifying priorities for intervention. It adds to the measurement tool kit for children with dyskinetic CP by addressing functional impact of dyskinetic movements and postures. What this paper adds The Dyskinetic Cerebral Palsy Functional Impact Scale (D-FIS) assesses the perceived impact of dyskinesia on daily activities in children with cerebral palsy (CP). The D-FIS demonstrates good construct validity and high internal consistency. The D-FIS is a clinically feasible, family-centred tool that fills a current gap in the dyskinetic CP assessment toolkit.

Rehabilitation in childhood-onset hyperkinetic movement disorders including dystonia: Treatment change in outcomes across the ICF and feasibility of outcomes for full trial evaluation

BACKGROUND

Childhood-onset hyperkinetic movement disorders (HMD), including dystonia are notoriously difficult to treat and there are limited studies showing successful medical, surgical or non-pharmacological interventions.

METHODS

This prospective study used grouped data (n = 22) from two studies of the Cognitive Orientation to daily Occupational Performance (CO-OP) Approach for patient-selected goals. Eligibility included aged 6-21 years, deep brain stimulation in place, with manual ability classification system level I-IV. Outcome was assessed on a range of patient-reported and clinician-rated measures across the International Classification of Function at end-treatment (10 weekly sessions) (series 1 and 2) and 3-month follow-up (series 1). Feasibility of outcomes to be used in a full trial were explored.

FINDINGS

Nineteen participants completed the intervention and were included in the analysis. Of the primary outcome measures, the self-reported Canadian Occupational Performance Measure showed improvement in goal performance (mean change 4.08, 95% CI [3.37,4.79] post-; 4.18 [5.10,5.26] follow-up), and satisfaction (4.03 [3.04,5.03) post-; 4.44 [3.07,5.82] follow-up]. The Assessment of Motor and Process Skills showed improved motor score (0.52 [0.01,1.03] at follow-up only, while the process score did not change. Objective blind-rated pooled data using the Performance Quality Rating Scale-individualized indicated significant change for trained goals (3.79 [3.37,4.21] post-; (4.01,5.10) follow-up] and untrained goals (1.90 [1.24,2.55] post 1.91 [0.23,3.60] follow-up]. Motor impairment assessed by the Burke-Fahn Motor Disability Rating Scale was unchanged (-3.26 [-6.62,0.09] post-; -1.11 [-8.05,5.82] follow-up). Improvement was also observed in self-efficacy (0.97 [0.47,1.47] post-; 1.37 [1.91-0.83] follow-up) and Quality of Life (0.12 [0.03-0.22] follow-up). Goal improvement; self-efficacy and quality of life captured significant change post-intervention. This improvement was shown despite no change on impairment-related measures and were shown to be feasible measures to use in a larger study of CO-OP for this population.

Dystonia Management: What to Expect From the Future? The Perspectives of Patients and Clinicians Within DystoniaNet Europe

Improved care for people with dystonia presents a number of challenges. Major gaps in knowledge exist with regard to how to optimize the diagnostic process, how to leverage discoveries in pathophysiology into biomarkers, and how to develop an evidence base for current and novel treatments. These challenges are made greater by the realization of the wide spectrum of symptoms and difficulties faced by people with dystonia, which go well-beyond motor symptoms. A network of clinicians, scientists, and patients could provide resources to facilitate information exchange at different levels, share mutual experiences, and support each other's innovative projects. In the past, collaborative initiatives have been launched, including the American Dystonia Coalition, the European Cooperation in Science and Technology (COST-which however only existed for a limited time), and the Dutch DystonieNet project. The European Reference Network on Rare Neurological Diseases includes dystonia among other rare conditions affecting the central nervous system in a dedicated stream. Currently, we aim to broaden the scope of these initiatives to a comprehensive European level by further expanding the DystoniaNet network, in close collaboration with the ERN-RND. In line with the ERN-RND, the mission of DystoniaNet Europe is to improve care and quality of life for people with dystonia by, among other endeavors, facilitating access to specialized care, overcoming the disparity in education of medical professionals, and serving as a solid platform to foster international clinical and research collaborations. In this review, both professionals within the dystonia field and patients and caregivers representing Dystonia Europe highlight important unsolved issues and promising new strategies and the role that a European network can play in activating them.

Cognitive Strategy Training in Childhood-Onset Movement Disorders: Replication Across Therapists

Objective: To explore preliminary effectiveness of the Cognitive Orientation to daily Occupational Performance (CO-OP) Approach in improving outcomes in childhood-onset hyperkinetic movement disorders (HMDs) including dyskinetic cerebral palsy following deep brain stimulation (DBS) across UK clinical occupational therapists. Methods: Randomized, multiple-baseline, Single Case Experimental Design N-of-1 trial with replications across participants. Five self-selected goals were identified: three goals were worked on during CO-OP and two goals were left untreated and used to assess skills transfer. Participants were between 6 and 21 years and had received DBS surgery with baseline Manual Ability Classification System (MACS) levels I-IV. Participants were randomized to typical or extended baseline (2 vs. 6 weeks), followed by 10 weekly individual CO-OP sessions. The primary outcome was functional performance measured by the Performance Quality Rating Scale-Individualized (PQRS-I), assessed before, during, and following treatment. Outcome assessors were blinded to baseline allocation, session number, and assessment time. A non-overlapping index, Tau-U, was used to measure effect size. Results: Of the 12 participants recruited, 10 commenced and completed treatment. In total, 63% of trained goals improved with effect sizes 0.66-1.00 ("moderate" to "large" effect), seen for all children in at least one goal. Skills transfer was found in 37% of the untrained goals in six participants. Conclusions: Cognitive strategy use improved participant-selected functional goals in childhood-onset HMD, more than just practice during baseline. Preliminary effectiveness is shown when the intervention is delivered in clinical practice by different therapists in routine clinical settings.

Pain in children with dyskinetic and mixed dyskinetic/spastic cerebral palsy

AIM

To evaluate pain prevalence and characteristics in children and adolescents with predominant dyskinetic and mixed (dyskinetic/spastic) cerebral palsy (CP) motor types.

METHOD

Seventy-five participants with a diagnosis of CP and confirmed dyskinetic or mixed (dyskinetic/spastic) motor type took part in a multisite cross-sectional study. The primary outcome was carer-reported pain prevalence (preceding 2wks) measured using the Health Utilities Index-3. Secondary outcomes were chronicity, intensity, body locations, quality of life, and activity impact.

RESULTS

Mean participant age was 10 years 11 months (SD 4y 2mo, range 5-18y). There were 44 males and 31 females and 37 (49%) had predominant dyskinetic CP. Pain was prevalent in 85% and it was chronic in 77% of participants. Fifty-two per cent experienced moderate-to-high carer-reported pain intensity, which was significantly associated with predominant dyskinetic motor types (p=0.008). Pain occurred at multiple body locations (5 out of 21), with significantly increased numbers of locations at higher Gross Motor Function Classification System levels (p=0.02). Face, jaw, and temple pain was significantly associated with predominant dyskinetic motor types (p=0.005). Poorer carer proxy-reported quality of life was detected in those with chronic pain compared to those without (p=0.03); however, chronic pain did not affect quality of life for self-reporting participants.

INTERPRETATION

Pain was highly prevalent in children and adolescents with predominant dyskinetic and mixed (dyskinetic/spastic) motor types, highlighting a population in need of lifespan pain management.

WHAT THIS PAPER ADDS

Chronic pain prevalence in children and adolescents with predominant dyskinetic and mixed (dyskinetic/spastic) motor types is high. Pain occurs across multiple body locations in predominant dyskinetic and mixed (dyskinetic/spastic) motor types. Less recognized locations of pain include the face, jaw, and temple for predominant dyskinetic motor types.

Deep brain stimulation reduces pain in children with dystonia, including in dyskinetic cerebral palsy

AIM

To establish the prevalence of dystonic pain in children and their response to deep brain stimulation (DBS).

METHOD

Dystonic pain was assessed in a cohort of 140 children, 71 males and 69 females, median age 11 years 11 months (range 3y-19y 1mo), undergoing DBS in our centre over a period of 10 years. The cohort was divided into aetiological dystonia groups: 1a, inherited; 1b, heredodegenerative; 2, acquired; and 3, idiopathic. Motor responses were measured with the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS).

RESULTS

Dystonic pain was identified in 63 (45%) patients, 38% of whom had a diagnosis of cerebral palsy (CP). Dystonic pain improved in 90% of children and in all aetiological subgroups 1 year after DBS, while the BFMDRS motor score improved in 70%. Statistically significant improvement (p<0.01) was noted for the whole cohort on the Numerical Pain Rating Scale (n=27), Paediatric Pain Profile (n=17), and Caregivers Priorities and Child Health Index of Life with Disabilities questionnaire (n=48). There was reduction of pain severity, frequency, and analgesia requirement. Findings were similar for the whole cohort and aetiological subgroups other than the inherited heredodegenerative group where the improvement did not reach statistical significance.

INTERPRETATION

Dystonic pain is frequent in children with dystonia, including those with CP, who undergo DBS; this can be an important, realizable goal of surgery irrespective of aetiology. We encourage the use of multimodal approach in pain research to reduce the risk of bias.

Delayed Diagnoses of SGCE Myoclonus-Dystonia

Background:

Myoclonus-dystonia due to SGCE mutations (OMIM: 159900) most commonly presents during childhood with mainly upper body myoclonus, and mild dystonia affecting the neck and arms.

Case reports:

Herein, we report patients misdiagnosed during childhood with Tourette syndrome and dyskinetic cerebral palsy, and, during adulthood, found to harbor SGCE frameshift mutations.

Discussion:

Myoclonus-dystonia may be underdiagnosed due to phenotypic misclassification during childhood. SGCE mutations should be included in the differential diagnosis of childhood movement disorders that ostensibly manifest with tics, myoclonus, or abnormal posturing secondary to dystonia and/or spasticity.

Highlights:

Due to pleiotropy, variable penetrance, broad differential, and hereditary effects of imprinting, the diagnosis of a disorder of childhood onset, myoclonus-dystonia due to SGCE mutations, may be delayed until adulthood, often compromising appropriate clinical management and genetic counseling.

Deep brain stimulation for the treatment of cerebral palsy: A review

Deep brain stimulation (DBS) has been used as a safe and effective neuromodulation technique for treatment of various diseases. A large number of patients suffering from movement disorders such as dyskinesia may benefit from DBS. Cerebral palsy (CP) is a group of permanent disorders mainly involving motor impairment, and medical interventions are usually unsatisfactory or temporarily active, especially for dyskinetic CP. DBS may be another approach to the treatment of CP. In this review we discuss the targets for DBS and the mechanisms of action for the treatment of CP, and focus on presurgical assessment, efficacy for dystonia and other symptoms, safety, and risks.

Deep Brain Stimulation of the Internal Pallidum in Lesch-Nyhan Syndrome: Clinical Outcomes and Connectivity Analysis

BACKGROUND

Lesch-Nyhan syndrome (LNS) is a rare genetic disorder characterized by a deficiency of hypoxanthine-guanine phosphoribosyltransferase enzyme. It manifests during infancy with compulsive self-mutilation behavior associated with disabling generalized dystonia and dyskinesia. Clinical management of these patients poses an enormous challenge for medical teams and carers.

OBJECTIVES

We report our experience with bilateral deep brain stimulation (DBS) of the globus pallidus internus (GPi) in the management of this complex disorder.

MATERIALS AND METHODS

Preoperative and postoperative functional assessment data prospectively collected by a multidisciplinary pediatric complex motor disorders team, including imaging, neuropsychology, and neurophysiology evaluations were analyzed with regards to motor and behavioral control, goal achievement, and patient and caregivers' expectations.

RESULTS

Four male patients (mean age 13 years) underwent DBS implantation between 2011 and 2018. Three patients received double bilateral DBS electrodes within the posteroventral GPi and the anteromedial GPi, whereas one patient had bilateral electrodes placed in the posteroventral GPi only. Median follow-up was 47.5 months (range 22-98 months). Functional improvement was observed in all patients and discussed in relation to previous reports. Analysis of structural connectivity revealed significant correlation between the involvement of specific cortical regions and clinical outcome.

CONCLUSION

Combined bilateral stimulation of the anteromedial and posteroventral GPi may be considered as an option for managing refractory dystonia and self-harm behavior in LNS patients. A multidisciplinary team-based approach is essential for patient selection and management, to support children and families, to achieve functional improvement and alleviate the overall disease burden for patients and caregivers.

The Effectiveness of Deep Brain Stimulation in Dystonia: A Patient-Centered Approach

Background:

To systematically evaluate the effectiveness of deep brain stimulation of the globus pallidus internus (GPi-DBS) in dystonia on pre-operatively set functional priorities in daily living.

Methods:

Fifteen pediatric and adult dystonia patients (8 male; median age 32y, range 8–65) receiving GPi-DBS were recruited. All patients underwent a multidisciplinary evaluation before and 1-year post DBS implantation. The Canadian Occupational Performance Measure (COPM) first identified and then measured changes in functional priorities. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) was used to evaluate dystonia severity.

Results:

Priorities in daily functioning substantially varied between patients but showed significant improvements on performance and satisfaction after DBS. Clinically significant COPM-score improvements were present in 7/8 motor responders, but also in 4/7 motor non-responders.

Discussion:

The use of a patient-oriented approach to measure GPi-DBS effectiveness in dystonia provides an unique insight in patients’ priorities and demonstrates that tangible improvements can be achieved irrespective of motor response.

Highlights

Long term perceptions of illness and self after Deep Brain Stimulation in pediatric dystonia: A narrative research

BACKGROUND

Deep Brain Stimulation (DBS) is increasingly used in pediatric patients affected by isolated dystonia, with excellent results. Despite well documented long-term effects on motor functioning, information on quality of life and social adaptation is almost lacking.

OBJECTIVES

The present study aims to explore the experience of illness and the relation with the device in adult patients suffering from dystonia who underwent DBS surgery in pediatric age.

METHODS

A narrative inquiry approach was used to collect patients' narratives of their experience with dystonia and DBS stimulator. A written interview was administered to 8 patients over 18 years old with generalized isolated dystonia who had undergone pallidal DBS implantation in childhood. A thematic analysis was realized to examine the narratives collected.

RESULTS

Five main themes emerged: "relationship with the disease", "experience related to DBS procedure", "relationship with one's own body", "fears", "thoughts about future". Despite a general satisfaction in relation to DBS intervention, some patients expressed difficulties, such as the acceptance of changes in one's own body, concerns and fears regarding the device and the future, also considering the critical phase of transition from childhood to adulthood.

CONCLUSIONS

These results suggest that further research is needed to understand the contribution of psychological, as much as medical, aspects to the overall outcome of the intervention. The present explorative study encourages a deeper investigations of psychological aspects of patients, in order to plan a tailored care path and to decide whether to suggest a psychological support, both before and after the intervention.

The lived experience of chronic pain and dyskinesia in children and adolescents with cerebral palsy

BACKGROUND

To explore the lived experience of chronic pain and dyskinesia in children and adolescents with cerebral palsy.

METHODS

A convergent parallel mixed methods design was undertaken. First, a quantitative cross-sectional study of participants able to self-report their quality of life was undertaken. This study characterised pain chronicity, intensity, body locations, and quality of life. Second, semi-structured interviews were undertaken with a subset of children and adolescents experiencing chronic pain.

RESULTS

Twenty-five children and adolescents took part in the cross-sectional study, 23 of whom experienced chronic pain and 13 of moderate intensity. Pain was often located in multiple bodily regions (6/21), with no trends in quality of life outcomes detected. Eight participated in semi-structured interviews, which identified three key themes including 'lives embedded with dyskinesia', 'real world challenges of chronic pain', and 'still learning strategies to manage their pain and dyskinesia'.

CONCLUSIONS

A high proportion of children and adolescents with cerebral palsy and dyskinesia who were able to self-report experienced chronic pain. The physical and emotional impacts of living with chronic pain and dyskinesia existed along a spectrum, from those with lesser to greater extent of their impacts. Children and adolescents may benefit from targeted chronic pain education and management within bio-psychosocial models.

Clinical phenotypes associated with outcomes following deep brain stimulation for childhood dystonia

OBJECTIVE

Although deep brain stimulation (DBS) is an accepted treatment for childhood dystonia, there is significant heterogeneity in treatment response and few data are available to identify ideal surgical candidates.

METHODS

Data were derived from a systematic review and individual patient data meta-analysis of DBS for dystonia in children that was previously published. Outcomes were assessed using the Burke-Fahn-Marsden Dystonia Rating Scale for movement (BFMDRS-M) and for disability (BFMDRS-D). The authors used partial least squares, bootstrapping, and permutation statistics to extract patterns of contributions of specific preoperative characteristics to relationship with distinct outcomes, in all patients and in patients with primary and secondary dystonia separately.

RESULTS

Of 301 children undergoing DBS for dystonia, 167 had primary dystonia, 125 secondary dystonia, and 9 myoclonus dystonia. Three dissociable preoperative phenotypes (latent variables) were identified and associated with the following: 1) BFMDRS-M at last follow-up; 2) relative change in BFMDRS-M score; and 3) relative change in BFMDRS-D score. The phenotype of patients with secondary dystonia, with a high BFMDRS-M score and truncal involvement, undergoing DBS at a younger age, was associated with a worse postoperative BFMDRS-M score. Children with primary dystonia involving the trunk had greater improvement in BFMDRS-M and -D scores. Those with primary dystonia of shorter duration and proportion of life with disease, undergoing globus pallidus DBS, had greater improvements in BFMDRS-D scores at long-term follow-up.

CONCLUSIONS

In a comprehensive, data-driven, multivariate analysis of DBS for childhood dystonia, the authors identified novel and dissociable patient phenotypes associated with distinct outcomes. The findings of this report may inform surgical candidacy for DBS.

Pharmacological management of abnormal tone and movement in cerebral palsy

BACKGROUND

The evidence base to guide the pharmacological management of tone and abnormal movements in cerebral palsy (CP) is limited, as is an understanding of routine clinical practice in the UK. We aimed to establish details of motor phenotype and current pharmacological management of a representative cohort across a network of UK tertiary centres.

METHODS

Prospective multicentre review of specialist motor disorder clinics at nine UK centres, collecting data on clinical features and pharmacological management of children and young people (CYP) with CP over a single calendar month.

RESULTS

Data were collected from 275 CYP with CP reviewed over the calendar month of October 2017. Isolated dystonia or spasticity was infrequently seen, with a mixed picture of dystonia and spasticity ± choreoathetosis identified in 194/275 (70.5%) of CYP. A comorbid diagnosis of epilepsy was present in 103/275 (37.4%). The most commonly used medications for abnormal tone/movement were baclofen, trihexyphenidyl, gabapentin, diazepam and clonidine. Medication use appeared to be influenced separately by the presence of dystonia or spasticity. Botulinum toxin use was common (62.2%). A smaller proportion of children (12.4%) had undergone a previous neurosurgical procedure for tone/movement management.

CONCLUSIONS

CYP with CP frequently present with a complex movement phenotype and comorbid epilepsy. They have multiple therapy, medical and surgical management regimens. Future trials of therapeutic, pharmacological or surgical interventions in this population must adequately encompass this complexity in order to be translatable to clinical practice.

Despite dystonia: natural history of delayed-onset pediatric secondary dystonia

Background: Dystonia is a movement disorder involving involuntary movements and/or postures of the limbs, trunk, neck or face. Secondary dystonia following brain injury is uncommon, with unfavorable long-term consequences. Given the limited evidence regarding pediatric secondary dystonia, this study's aim was to document the natural history of the condition and the effect of interventions on its symptomatology. Methods: We describe three cases of girls (age 8 to 11 y) who developed dystonia secondary to an acquired brain injury, received intensive rehabilitation treatments and were followed for 8-33 months post-injury. In all three cases, secondary dystonia appeared 1-3 months post-insult. Results: In none of the cases was there alleviation of dystonic symptoms over time despite physical and pharmacological interventions; in two cases the dystonic hand is now used as an assisting hand only, whereas in the third it is completely non-functional. However, despite their impairment, two girls achieved basic functional independence and one is partly independent in activities of daily living. Conclusions: Rehabilitation professionals who work with pediatric patients susceptible to developing secondary dystonia should be aware of its possible consequences and inform families and staff. Intensive task-specific training during rehabilitation may be key to regaining overall functional capabilities despite residual impairment.

Management of pain in children and adolescents with cerebral palsy: a systematic review

AIM

To determine the efficacy of interventions for the management of pain in children and adolescents with cerebral palsy (CP).

METHOD

Electronic databases were searched from the earliest date possible to April 2018 using a mixture of subject headings and free text. Inclusion criteria comprised of studies with (1) diagnosis of CP, (2) under the age of 18 years, (3) intervention for the management of pain, (4) outcome measure of pain, and (5) studies published in English-language peer-reviewed journals.

RESULTS

Fifty-seven studies met the eligibility criteria. Pain related to (n=number of studies): hypertonia (n=17), spastic hip disease (n=13), procedures for the management of CP (n=7), postoperative (n=18), and other (n=2). Most of the studies were of level III to level V evidence.

INTERPRETATION

There is level II evidence to support intrathecal baclofen therapy for pain secondary to hypertonia in spastic and spastic-dyskinetic CP, and non-pharmacological interventions for procedural pain and pharmacological interventions for postoperative pain. Most studies were restricted by retrospective design and limited use of validated outcome measures. Future research is needed to explore multidisciplinary interventions for chronic pain and pain secondary to dystonia. Clinicians and researchers would benefit from a standardized approach to pain assessment.

WHAT THIS PAPER ADDS

The strongest evidence exists for pharmacological treatments for postoperative pain in children and adolescents with cerebral palsy (CP). There is moderate evidence for the efficacy of intrathecal baclofen for pain related to hypertonia in predominately spastic CP. There is a lack of standardization in the assessment of pain. There is limited evidence for multimodal and non-pharmacological strategies in paediatric CP.

Cognitive approach to rehabilitation in children with hyperkinetic movement disorders post-DBS

OBJECTIVE

This proof-of-concept feasibility trial examined the potential of the Cognitive Orientation to daily Occupational Performance Approach (CO-OP) to augment deep brain stimulation (DBS) outcomes in childhood-onset hyperkinetic movement disorders (HMD) including dystonia and dyskinetic cerebral palsy.

METHODS

This is a single case experimental design using multiple baseline as n-of-1 trial comprising 10 intervention sessions, with replications across participants (n = 10). Treatment focused on 3 participant-selected goals. Transfer was assessed on 2 additional untreated goals. Individuals enrolled were 6-21 years of age and had DBS in situ and sufficient manual ability. Primary outcome was functional performance change on the Performance Quality Rating Scale-Individualized (PQRS-i) measured before, during, and posttreatment, and at 3-month follow-up. Assessors of outcome were blinded to time of assessment, number of intervention session, and treatment allocation. To measure effect size, a nonoverlapping index, Tau-U, was used. Feasibility measures were captured.

RESULTS

One participant withdrew before baseline assessment. Effect sizes of at least 0.66 were seen at both posttreatment and follow-up with all participants showing improvements in at least one trained goal in PQRS-i. Six participants improved on all 3 goals and 2 improved on 2 trained goals. Two children showed deterioration in one trained goal each. Transfer to untrained goals was observed in 3 participants for a total of 5 goals. CO-OP was feasible and acceptable to all participants.

CONCLUSION

A cognitive-based, task-oriented approach to support performance of personally relevant functional skills enabling participation is acceptable in childhood-onset HMD post-DBS. Further, preliminary efficacy to improve outcomes and proof of concept with CO-OP has been established in this population.

CLASSIFICATION OF EVIDENCE

This study provides Class IV evidence that for children with HMD who had undergone DBS, CO-OP improves performance of personally relevant functional skills.

Motor and non-motor determinants of health-related quality of life in young dystonia patients

OBJECTIVES

To systematically investigate the relationship between motor and non-motor symptoms, and health-related quality of life (HR-QoL) in children and young adults with dystonia.

METHODS

In this prospective observational cross-sectional study, 60 patients (6-25 years) with childhood-onset dystonia underwent a multidisciplinary assessment of dystonia severity (Burke-Fahn-Marsden Dystonia Rating Scale, Global Clinical Impression), motor function (Gross Motor Function Measure, Melbourne Assessment of Unilateral Upper Limb Function), pain (visual analogue scale), intelligence (Wechsler Intelligence Scale), executive functioning (Behavior Rating Inventory of Executive Function) and anxiety/depression (Child/Adult Behavior Checklist). Measures were analyzed using a principal component analysis and subsequent multiple regression to evaluate which components were associated with HR-QoL (Pediatric Quality of life Inventory) for total group, and non-lesional (primary) and lesional (secondary) subgroups.

RESULTS

Patients (29 non-lesional, 31 lesional dystonia) had a mean age of 13.6 ± 5.9 years. The principal component analysis revealed three components: 1) motor symptoms; 2) psychiatric and behavioral symptoms; and 3) pain. HR-QoL was associated with motor symptoms and psychiatric and behavioral symptoms (R2 = 0.66) for the total sample and lesional dystonia, but in the non-lesional dystonia subgroup only with psychiatric and behavioral symptoms (R2 = 0.51).

CONCLUSIONS

Non-motor symptoms are important for HR-QoL in childhood-onset dystonia. We suggest a multidisciplinary assessment of motor and non-motor symptoms to optimize individual patient management.

Protocol for N-of-1 trials with replications across therapists for childhood-onset dystonia rehabilitation: Study 2: Protocole des essais à effectif unique avec répétitions par différents ergothérapeutes pour la réadaptation de la dystonie débutant dans l'enfance : Étude 2

BACKGROUND

Currently, no evidence-based rehabilitation interventions are available for hyperkinetic movement disorders (HMD), including dyskinetic cerebral palsy (CP). Among these highly heterogeneous disorders, dystonia is the predominant disorder. The Cognitive Orientation to daily Occupational Performance (CO-OP) Approach-a task-oriented, performance-based intervention to enable participation-is currently being evaluated for its potential as an intervention option.

PURPOSE

This paper reports the protocol for the second of two studies designed to evaluate the potential of CO-OP to improve functional outcomes for individuals with HMD following deep brain stimulation (DBS). This second study is a systematic replication across multiple treating therapists from multiple centres.

METHOD

Systematic replications will be used across centres and treating therapists trained in the CO-OP, using a series of randomized multiple-baseline N-of-1 trials. Participants will be ages 6 to 21 years with HMD and DBS as indicated by the Manual Ability Classification System. Data collection will involve multiple data points collected at baseline, during intervention, and after intervention. The intervention will involve occupation-based goal setting followed by 10 individualized CO-OP sessions. The primary outcome measures are the Performance Quality Rating Scale and the Canadian Occupational Performance Measure. Outcome data will be plotted over time for each participant and supplemented with graph statistical analysis and estimate size effect for N-of-1 trials.

IMPLICATIONS

The results of this study will help to inform future training procedures and future clinical trials.

Protocol for N-of-1 trials proof of concept for rehabilitation of childhood-onset dystonia: Study 1: Protocole des essais de validation à effectif unique pour la réadaptation de la dystonie débutant dans l'enfance : Étude 1

BACKGROUND

Hyperkinetic movement disorders (HMD) are a heterogeneous group of neurological conditions among which dystonia is the predominant disorder and dyskinetic cerebral palsy the largest secondary dystonia group. Currently, there are no evidence-based, non-medical management options for childhood HMD. The Cognitive Orientation to daily Occupational Performance (CO-OP) Approach is a task-oriented, performance-based intervention that focuses on participation.

PURPOSE

This paper reports the protocol for a proof-of-concept study to assess feasibility and preliminary evidence regarding efficacy of CO-OP for HMD following deep brain stimulation (DBS).

METHOD

A series of N-of-1 trials with replications will be conducted with children, ages 6 and 21 years with HMD and DBS as indicated by the Manual Ability Classification System. Ten individualized CO-OP sessions, with multiple baselines before, during, and after, will be completed. The primary outcome measures are the Performance Quality Rating Scale and the Assessment of Motor and Process Skills. Outcome data will be plotted over time for each participant and supplemented with graph statistical analysis and effect size estimates.

IMPLICATIONS

A written protocol will be developed based on evidence and feedback incorporating any changes to the CO-OP intervention for children and young people with HMD, as per the Medical Research Council's Framework for Complex Interventions.

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.

Pharmacological and neurosurgical interventions for managing dystonia in cerebral palsy: a systematic review

AIM

To systematically review evidence for pharmacological/neurosurgical interventions for managing dystonia in individuals with cerebral palsy (CP) to inform a care pathway.

METHOD

Searches included studies with a minimum of five participants with dystonia in CP receiving oral baclofen, benzodiazepines (clonazepam, diazepam, lorazepam), clonidine, gabapentin, levodopa, trihexyphenidyl, botulinum toxin, intrathecal baclofen (ITB), or deep brain stimulation (DBS). Evidence was classified according to American Academy of Neurology guidelines.

RESULTS

Twenty-eight articles underwent data extraction: one levodopa, five trihexyphenidyl, three botulinum toxin, six ITB, and 13 DBS studies. No articles for oral baclofen, benzodiazepines, clonidine, or gabapentin met the inclusion criteria. Evidence for reducing dystonia was level C (possibly effective) for ITB and DBS; level C (possibly ineffective) for trihexyphenidyl; and level U (inadequate data) for botulinum toxin.

INTERPRETATION

For dystonia reduction, ITB and DBS are possibly effective, whereas trihexyphenidyl was possibly ineffective. There is insufficient evidence to support oral medications or botulinum toxin to reduce dystonia. There is insufficient evidence for pharmacological and neurosurgical interventions to improve motor function, decrease pain, and ease caregiving. The majority of the pharmacological and neurosurgical management of dystonia in CP is based on clinical expert opinion.

WHAT THIS PAPER ADDS

Intrathecal baclofen and deep brain stimulation are possibly effective in reducing dystonia. Current evidence does not support effectiveness of oral medications or botulinum toxin to reduce dystonia. Evidence is inadequate for pharmacological/neurosurgical interventions impact on improving motor function, pain/comfort, and easing caregiving. The majority of the care pathway rests on expert opinion.

Advances in pharmacotherapies for movement disorders in children: current limitations and future progress

PURPOSE OF REVIEW

In childhood, movement disorders are generated by a very large number of disorders of the nervous system, and the very different developmental ages at which these occur make studies of pharmacotherapy efficacy extremely difficult. In most clinical practices, medication used in management is by trial and error, and limited by lack of efficacy and/or adverse drug reactions leading to drug intolerance. Nevertheless, symptom reduction using polypharmacy must be balanced against any accompanying comorbidities such as poor attention and concentration, constipation, ileus, urinary retention, blurred vision sedation and respiratory depression.

RECENT FINDINGS

A 'personalised medicine' approach may lead to specific management breakthroughs that are beneficial to a wider number of children. At present, neuromodulation with implantable devices offers greater proven efficacy for dystonia, myoclonus and dystonic-choreoathetosis, but enteral, intravenous and, more recently, transdermal medication strategies with clonidine patches and enteral gabapentin may provide important relief for both home management and critical care settings.

SUMMARY

The current review brings the clinician up-to-date with the latest, albeit limited, thinking on the pharmacological management of movement disorders in children by focussing on goal-directed outcome measures to improve clinical decision-making in an evidence-light clinical setting.

Clinical presentation and management of dyskinetic cerebral palsy

Cerebral palsy is the most frequent cause of severe physical disability in childhood. Dyskinetic cerebral palsy (DCP) is the second most common type of cerebral palsy after spastic forms. DCP is typically caused by non-progressive lesions to the basal ganglia or thalamus, or both, and is characterised by abnormal postures or movements associated with impaired tone regulation or movement coordination. In DCP, two major movement disorders, dystonia and choreoathetosis, are present together most of the time. Dystonia is often more pronounced and severe than choreoathetosis, with a major effect on daily activity, quality of life, and societal participation. The pathophysiology of both movement disorders is largely unknown. Some emerging hypotheses are an imbalance between indirect and direct basal ganglia pathways, disturbed sensory processing, and impaired plasticity in the basal ganglia. Rehabilitation strategies are typically multidisciplinary. Use of oral drugs to provide symptomatic relief of the movement disorders is limited by adverse effects and the scarcity of evidence that the drugs are effective. Neuromodulation interventions, such as intrathecal baclofen and deep brain stimulation, are promising options.

Spasticity, dyskinesia and ataxia in cerebral palsy: Are we sure we can differentiate them?

OBJECTIVE

Cerebral palsy (CP) can be classified as spastic, dyskinetic, ataxic or combined. Correct classification is essential for symptom-targeted treatment. This study aimed to investigate agreement among professionals on the phenotype of children with CP based on standardized videos.

METHODS

In a prospective, observational pilot study, videos of fifteen CP patients (8 boys, mean age 11 ± 5 y) were rated by three pediatric neurologists, three rehabilitation physicians and three movement disorder specialists. They scored the presence and severity of spasticity, ataxia or dyskinesias/dystonia. Inter- and intraobserver agreement were calculated using Cohen's and Fleiss' kappa.

RESULTS

We found a fair inter-observer (κ = 0.36) and moderate intra-observer agreement (κ = 0.51) for the predominant motor symptom. This only slightly differed within the three groups of specialists (κ = 0.33-0.55).

CONCLUSION

A large variability in the phenotyping of CP children was detected, not only between but also within clinicians, calling for a discussing on the operational definitions of spasticity, dystonia and ataxia. In addition, the low agreement found in our study questions the reliability of use of videos to measure intervention outcomes, such as deep brain stimulation in dystonic CP. Future studies should include functional domains to assess the true impact of management options in this highly challenging patient population.

Clinical rating scale for pantothenate kinase-associated neurodegeneration: A pilot study

BACKGROUND

Pantothenate kinase-associated neurodegeneration is a progressive neurological disorder occurring in both childhood and adulthood. The objective of this study was to design and pilot-test a disease-specific clinical rating scale for the assessment of patients with pantothenate kinase-associated neurodegeneration.

METHODS

In this international cross-sectional study, patients were examined at the referral centers following a standardized protocol. The motor examination was filmed, allowing 3 independent specialists in movement disorders to analyze 28 patients for interrater reliability assessment. The scale included 34 items (maximal score, 135) encompassing 6 subscales for cognition, behavior, disability, parkinsonism, dystonia, and other neurological signs.

RESULTS

Forty-seven genetically confirmed patients (30 ± 17 years; range, 6-77 years) were examined with the scale (mean score, 62 ± 21; range, 20-106). Dystonia with prominent cranial involvement and atypical parkinsonian features were present in all patients. Other common signs were cognitive impairment, psychiatric features, and slow and hypometric saccades. Dystonia, parkinsonism, and other neurological features had a moderate to strong correlation with disability. The scale showed good internal consistency for the total scale (Cronbach's α = 0.87). On interrater analysis, weighted kappa values (0.30-0.93) showed substantial or excellent agreement in 85% of the items. The scale also discriminated a subgroup of homozygous c.1583C>T patients with lower scores, supporting construct validity for the scale.

CONCLUSIONS

The proposed scale seems to be a reliable and valid instrument for the assessment of pediatric and adult patients with pantothenate kinase-associated neurodegeneration. Additional validation studies with a larger sample size will be required to confirm the present results and to complete the scale validation testing. © 2017 International Parkinson and Movement Disorder Society.

Intrathecal baclofen therapy in paediatrics: a study protocol for an Australian multicentre, 10-year prospective audit

INTRODUCTION

Increasing clinical use of Intrathecal baclofen (ITB) in Australian tertiary paediatric hospitals, along with the need for standardised assessment and reporting of adverse events, saw the formation of the Australian Paediatric ITB Research Group (APIRG). APIRG developed a National ITB Audit tool designed to capture clinical outcomes and adverse events data for all Australian children and adolescents receiving ITB therapy.

METHODS AND ANALYSIS

The Australian ITB Audit is a 10 year, longitudinal, prospective, clinical audit collecting all adverse events and assessment data across body functions and structure, participation and activity level domains of the ICF. Data will be collected at baseline, 6 and 12 months with ongoing capture of all adverse event data. This is the first Australian study that aims to capture clinical and adverse event data from a complete population of children with neurological impairment receiving a specific intervention between 2011 and 2021. This multi-centre study will inform ITB clinical practice in children and adolescents, direct patient selection, record and aid decision making regarding adverse events and investigate the impact of ITB therapy on family and patient quality of life.

ETHICS AND DISSEMINATION

This project was approved by the individual Human Research Ethics committees at the six Australian tertiary hospitals involved in the study. Results will be published in various peer reviewed journals and presented at national and international conferences.

TRIAL REGISTRATION NUMBER

ACTRN 12610000323022; Pre-results.

The relationship of dystonia and choreoathetosis with activity, participation and quality of life in children and youth with dyskinetic cerebral palsy

AIM

To relate dystonia and choreoathetosis with activity, participation and quality of life (QOL) in children and youth with dyskinetic Cerebral Palsy (CP).

METHODS

Fifty-four participants with dyskinetic CP (mean age 14y6m, SD 4y2m, range 6-22y) were included. The Dyskinesia Impairment Scale (DIS) was used to evaluate dystonia and choreoathetosis. Activity, participation and quality of life (QOL) were assessed with the Gross Motor Function Measure (GMFM), the Functional Mobility Scale (FMS), the Jebsen-Taylor Hand Function Test (JTT), the ABILHAND-Kids Questionnaire (ABIL-K), the Life Habits Kids (LIFE-H) and the Quality of Life Questionnaire for children with CP (CP-QOL). Spearman's rank correlation coefficient (r_s) was used to assess the relationship between the movement disorders and activity, participation and QOL measures.

RESULTS

Significant negative correlations were found between dystonia and the activity scales with Spearman's rank correlation coefficient (r_s) varying between -0.65 (95% CI = -0.78 to -0.46) and -0.71 (95% CI = -0,82 to -0.55). Correlations were also found with the LIFE-H (r_s = -0.43; 95%CI = -0.64 to -0.17) and the CP-QOL (r_s = -0.32; 95%CI = -0.56 to -0.03). As far as choreoathetosis is concerned, no or only weak relationships were found with the activity, participation and quality of life scales.

INTERPRETATION

This cross-sectional study is the first to examine the relationship of dystonia and choreoathetosis in dyskinetic CP with the level of activity, participation and QOL. The results revealed dystonia has a higher impact on activity, participation and quality of life than choreoathetosis. These findings seem to suggest it is necessary to first focus on dystonia reducing intervention strategies and secondly on choreoathetosis.

Deep brain stimulation for childhood dystonia: Is 'where' as important as in 'whom'?

Deep brain stimulation (DBS) has become a mainstay of dystonia management in adulthood. Typically targeting electrode placement in the GPi, sustained improvement in dystonic symptoms are anticipated in adults with isolated genetic dystonias. Dystonia in childhood is more commonly a symptomatic condition, with dystonia frequently expressed on the background of a structurally abnormal brain. Outcomes following DBS in this setting are much more variable, the reasons for which have yet to be elucidated. Much of the focus on improving outcomes following DBS in dystonia management has been on the importance of patient selection, with, until recently, little discussion of the choice of target. In this review, we advance the argument that patient selection for DBS in childhood cannot be made separate from the choice of target nuclei. The anatomy of common DBS targets is considered, and factors influencing their choice for electrode insertion are discussed. We propose an "ABC" for DBS in childhood dystonia is proposed: Appropriate Child selected; Best nuclei chosen for electrode insertion; Correct position within that nucleus.

Deep brain stimulation in cerebral palsy: Challenges and opportunities

Cerebral palsy (CP) is the most common cause for acquired dystonia in childhood. Pharmacological treatment is often unsatisfactory and side effects are frequently dose-limiting. Data on outcome of DBS in paediatric patients with dyskinetic CP is very limited and heterogeneous. Reasons for the variability in responses are not entirely known yet. Interestingly, some CP-patients seem to improve subjectively on pallidal stimulation but without measurable changes in impairment scales. Besides dystonia scales, the use of sensitive age-dependent assessments tools is therefore reasonable to capture the full effect. As the course of disease duration as well as the age at operation seem to correlate with DBS outcome in patients with dystonia, DBS at an early stage of development might be beneficial for some of these patients. For the future, well-conducted trials as well as data collection in the international registry is of major importance to increase knowledge about DBS in CP patients, especially those implanted at a young age. Furthermore, selection criteria and guidelines or treatment standards are needed to improve the service for children with dyskinetic CP - especially in light of unsatisfactory medical treatment options.

Bilateral globus pallidus internus deep brain stimulation for dyskinetic cerebral palsy supports success of cochlear implantation in a 5-year old ex-24 week preterm twin with absent cerebellar hemispheres

BACKGROUND

Early onset dystonia (dyskinesia) and deafness in childhood pose significant challenges for children and carers and are the cause of multiple disability. It is particularly tragic when the child cannot make use of early cochlear implantation (CI) technology to relieve deafness and improve language and communication, because severe cervical and truncal dystonia brushes off the magnetic amplifier behind the ears. Bilateral globus pallidus internus (GPi) deep brain stimulation (DBS) neuromodulation can reduce dyskinesia, thus supporting CI neuromodulation success.

METHODS

We describe the importance of the order of dual neuromodulation surgery for dystonia and deafness. First with bilateral GPi DBS using a rechargeable ACTIVA-RC neurostimulator followed 5 months later by unilateral CI with a Harmony (BTE) Advanced Bionics Hi Res 90 K cochlear device. This double neuromodulation was performed in series in a 12.5 kg 5 year-old ex-24 week gestation-born twin without a cerebellum.

RESULTS

Relief of dyskinesia enabled continuous use of the CI amplifier. Language understanding and communication improved. Dystonic storms abated. Tolerance of sitting increased with emergence of manual function. Status dystonicus ensued 10 days after ACTIVA-RC removal for infection-erosion at 3 years and 10 months. He required intensive care and DBS re-implantation 3 weeks later together with 8 months of hospital care. Today he is virtually back to the level of functioning before the DBS removal in 2012 and background medication continues to be slowly weaned.

CONCLUSION

This case illustrates that early neuromodulation with DBS for dystonic cerebral palsy followed by CI for deafness is beneficial. Both should be considered early i.e. under the age of five years. The DBS should precede the CI to maximise dystonia reduction and thus benefits from CI. This requires close working between the paediatric DBS and CI services.

Complications of Deep Brain Stimulation (DBS) for dystonia in children - The challenges and 10 year experience in a large paediatric cohort

Deep brain stimulation (DBS) has been increasingly used for primary and secondary movement disorders in children and young people. Reports of hardware related complications have been sparse for this population and from small cohorts of patients. We report DBS complications from a single large DBS centre with 10 year experience. Data was collected as a prospective audit and additionally from a questionnaire on recharging of the stimulators. 129 patients with a minimum 6 months follow up were identified, mean age10.8 y (range 3.0-18.75), mean follow up 3.3y (range 0.5-10.3), weight 10.4-94.2 kg, 126 new implants (92 Activa RC) and 69 revisions for reasons other than infection. 26 patients were 7y or younger. Surgical site infections (SSI) rates were 10.3% for new implants and revisions, lower 8.6% for new Activa RC and even lower, 4.7%, for new Activa RC in patients under 7y (1/21). SSI occurred within first 6 months and necessitated total system removal in 86% of those infected. Electrode/extension problems were recorded in 18.4% of patients, fracture in 4.6% malfunction in 7.7%, short extension 3.8% and electrode migration in 2.3%. Other complications involved clinically silent intracranial bleed in 1 patient, skin erosions (2.3%), unexpected switching off in 18.7% of Soletra/Kinetra and 3.4% of Activa RC, transient seroma at IPG site in postoperative period (8%). Of the 48 returned recharging questionnaires, 38% of families required recharger replacement and 23% experienced frequent problems maintaining connection during recharging. However, 83% of responders considered recharging not at all or only a little care burden. We identified lower than previously reported DBS infection rates particularly for patients under 7 years, but relatively high incidence of technical problems with electrodes, extensions and in particular recharging. This has to be considered when offering DBS for children with movement disorders.

A comparative historical and demographic study of the neuromodulation management techniques of deep brain stimulation for dystonia and cochlear implantation for sensorineural deafness in children

Cochlear implants for sensorineural deafness in children is one of the most successful neuromodulation techniques known to relieve early chronic neurodisability, improving activity and participation. In 2012 there were 324,000 recipients of cochlear implants globally.

AIM

To compare cochlear implant (CI) neuromodulation with deep brain stimulation (DBS) for dystonia in childhood and explore relations between age and duration of symptoms at implantation and outcome.

METHODS

Comparison of published annual UK CI figures for 1985-2009 with a retrospective cohort of the first 9 years of DBS for dystonia in children at a single-site Functional Neurosurgery unit from 2006 to 14.

RESULTS

From 2006 to 14, DBS neuromodulation of childhood dystonia increased by a factor of 3.8 to a total of 126 cases over the first 9 years, similar to the growth in cochlear implants which increased by a factor of 4.1 over a similar period in the 1980s rising to 527 children in 2009. The CI saw a dramatic shift in practice from implantation at >5 years of age at the start of the programme towards earlier implantation by the mid-1990s. Best language results were seen for implantation <5 years of age and duration of cochlear neuromodulation >4 years, hence implantation <1 year of age, indicating that severely deaf, pre-lingual children could benefit from cochlear neuromodulation if implanted early. Similar to initial CI use, the majority of children receiving DBS for dystonia in the first 9 years were 5-15 years of age, when the proportion of life lived with dystonia exceeds 90% thus limiting benefits.

CONCLUSION

Early DBS neuromodulation for acquired motor disorders should be explored to maximise the benefits of dystonia reduction in a period of maximal developmental plasticity before the onset of disability. Learning from cochlear implantation, DBS can become an accepted management option in children under the age of 5 years who have a reduced proportion of life lived with dystonia, and not viewed as a last resort reserved for only the most severe cases where benefits may be at their most limited.

What parents think and feel about deep brain stimulation in paediatric secondary dystonia including cerebral palsy: A qualitative study of parental decision-making

BACKGROUND

Dystonia is characterised by involuntary movements and postures. Deep Brain Stimulation (DBS) is effective in reducing dystonic symptoms in primary dystonia in childhood and to lesser extent in secondary dystonia. How families and children decide to choose DBS surgery has never been explored.

AIMS

To explore parental decision-making for DBS in paediatric secondary dystonia.

METHODS

Data was gathered using semi-structured interviews with eight parents of children with secondary dystonia who had undergone DBS. Interviews were analysed using Interpretative Phenomenological Analysis.

RESULTS

For all parents the decision was viewed as significant, with life altering consequences for the child. These results suggested that parents were motivated by a hope for a better life and parental duty. This was weighed against consideration of risks, what the child had to lose, and uncertainty of DBS outcome. Decisions were also influenced by the perspectives of their child and professionals.

CONCLUSIONS

The decision to undergo DBS was an ongoing process for parents, who ultimately were struggling in the face of uncertainty whilst trying to do their best as parents for their children. These findings have important clinical implications given the growing referrals for consideration of DBS childhood dystonia, and highlights the importance of further quantitative research to fully establish the efficacy of DBS in secondary dystonia to enhance informed decision-making.

German registry of paediatric deep brain stimulation in patients with childhood-onset dystonia (GEPESTIM)

BACKGROUND

Data on paediatric deep brain stimulation (DBS) is limited, especially for long-term outcomes, because of small numbers in single center series and lack of systematic multi-center trials.

OBJECTIVES

We seek to systematically evaluate the clinical outcome of paediatric patients undergoing DBS.

METHODS

A German registry on paediatric DBS (GEPESTIM) was created to collect data of patients with dystonia undergoing DBS up to the age of 18 years. Patients were divided into three groups according to etiology (group 1 inherited, group 2 acquired, and group 3 idiopathic dystonia).

RESULTS

Data of 44 patients with a mean age of 12.8 years at time of operation provided by 6 German centers could be documented in the registry so far (group 1 n = 18, group 2 n = 16, group 3 n = 10). Average absolute improvement after implantation was 15.5 ± 18.0 for 27 patients with pre- and postoperative Burke-Fahn-Marsden Dystonia Rating scale movement scores available (p < 0.001) (group 1: 19.6 ± 19.7, n = 12; group 2: 7.0 ± 8.9, n = 8; group 3: 19.2 ± 20.7, n = 7). Infection was the main reason for hardware removal (n = 6). 20 IPG replacements due to battery expiry were necessary in 15 patients at 3.7 ± 1.8 years after last implantation.

DISCUSSION

Pre- and postoperative data on paediatric DBS are very heterogeneous and incomplete but corroborate the positive effects of DBS on inherited and acquired dystonia. Adverse events including relatively frequent IPG replacements due to battery expiry seem to be a prominent feature of children with dystonia undergoing DBS. The registry enables collaborative research on DBS treatment in the paediatric population and to create standardized management algorithms in the future.

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.

Recognizing the Common Origins of Dystonia and the Development of Human Movement: A Manifesto of Unmet Needs in Isolated Childhood Dystonias

Dystonia in childhood may be severely disabling and often unremitting and unrecognized. Considered a rare disorder, dystonic symptoms in childhood are pervasive in many conditions including disorders of developmental delay, cerebral palsy (CP), autism, neurometabolic, neuroinflammatory, and neurogenetic disorders. Collectively, there is a need to recognize the role of early postures and movements which characterize phases of normal fetal, infant, and child development as a backdrop to the many facets of dystonia in early childhood neurological disorders and to be aware of the developmental context of dystonic symptoms. The role of cocontraction is explored throughout infancy, childhood, young adulthood, and in the elderly. Under-recognition of pervasive dystonic disorders of childhood, including within CP is reviewed. Original descriptions of CP by Gowers are reviewed and contemporary physiological demonstrations are used to illustrate support for an interpretation of the tonic labyrinthine response as a manifestation of dystonia. Early recognition and molecular diagnosis of childhood dystonia where possible are desirable for appropriate clinical stratification and future precision medicine and functional neurosurgery where appropriate. A developmental neurobiological perspective could also be useful in exploring new clinical strategies for adult-onset dystonia disorders focusing on environmental and molecular interactions and systems behaviors.

Advances in management of movement disorders in children

Movement disorders in children are causally and clinically heterogeneous and present in a challenging developmental context. Treatment options are broad ranging, from pharmacotherapy to invasive neuromodulation and experimental gene and stem cell therapies. The clinical effects of these therapies are variable and often poorly sustained, and only a few of the management strategies used in paediatric populations have been tested in randomised controlled studies with age-appropriate cohorts. Identification of the most appropriate treatment is uniquely challenging in children because of the incomplete knowledge about the pathophysiology of movement disorders and their influence on normal motor development; thus, effective therapeutic options for these children remain an unmet need. It is vital to transfer the expanding knowledge of the movement disorders into the development of novel symptomatic or, ideally, disease-modifying treatments, and to assess these therapeutic strategies in appropriately designed and well done trials.

Progression to musculoskeletal deformity in childhood dystonia

AIM

Dystonia is a movement disorder characterized by involuntary muscle contractions, resulting in abnormalities of posture and movement. Children with dystonia are at risk of developing fixed musculoskeletal deformities (FMDs). FMDs cause pain, limit function and participation and interfere with care. We aimed to explore factors relating to the development of FMD in a large cohort of children with dystonia.

METHOD

The case notes of all children referred to our Complex Motor Disorder service between July 2005 and December 2011 were reviewed. Data from 279 children (median age 9 years 10 months, Standard Deviation 4 years 2 months) with motor disorders including a prominent dystonic element were analyzed. Parametric accelerated failure time regression was used to identify the factors related to development of contractures.

RESULTS

FMDs were present at referral in more than half (n = 163, 58%) of cases. Three quarters (n = 120, 74%) of children with FMD had deformities around the hip, and 42% had spinal deformity (n = 68). Compared to pure primary dystonia, FMD onset was earlier with a diagnosis of secondary or heredodegenerative dystonia, and a mixed spastic-dystonic phenotype (all p < 0.001). FMD onset was also earlier with increasing Gross Motor Function Classification System (GMFCS) level (p < 0.001). The effect of aetiological classification was lost when controlling for GMFCS level and motor phenotype.

INTERPRETATION

Children with secondary or heredodegenerative dystonia are at greater risk of progression to FMD compared to primary dystonia, likely due to more severe dystonia within these groups. Children with additional spasticity are at particular risk, requiring close monitoring.

Burke-Fahn-Marsden dystonia severity, Gross Motor, Manual Ability, and Communication Function Classification scales in childhood hyperkinetic movement disorders including cerebral palsy: a 'Rosetta Stone' study

AIM

Hyperkinetic movement disorders (HMDs) can be assessed using impairment-based scales or functional classifications. The Burke-Fahn-Marsden Dystonia Rating Scale-movement (BFM-M) evaluates dystonia impairment, but may not reflect functional ability. The Gross Motor Function Classification System (GMFCS), Manual Ability Classification System (MACS), and Communication Function Classification System (CFCS) are widely used in the literature on cerebral palsy to classify functional ability, but not in childhood movement disorders. We explore the concordance of these three functional scales in a large sample of paediatric HMDs and the impact of dystonia severity on these scales.

METHOD

Children with HMDs (n=161; median age 10y 3mo, range 2y 6mo-21y) were assessed using the BFM-M, GMFCS, MACS, and CFCS from 2007 to 2013. This cross-sectional study contrasts the information provided by these scales.

RESULTS

All four scales were strongly associated (all Spearman's rank correlation coefficient rs >0.72, p<0.001), with worse dystonia severity implying worse function. Secondary dystonias had worse dystonia and less function than primary dystonias (p<0.001). A longer proportion of life lived with dystonia is associated with more severe dystonia (rs =0.42, p<0.001).

INTERPRETATION

The BFM-M is strongly linked with the GMFCS, MACS, and CFCS, irrespective of aetiology. Each scale offers interrelated but complementary information and is applicable to all aetiologies. Movement disorders including cerebral palsy can be effectively evaluated using these scales.

Cerebral palsy

Cerebral palsy is the most common cause of childhood-onset, lifelong physical disability in most countries, affecting about 1 in 500 neonates with an estimated prevalence of 17 million people worldwide. Cerebral palsy is not a disease entity in the traditional sense but a clinical description of children who share features of a non-progressive brain injury or lesion acquired during the antenatal, perinatal or early postnatal period. The clinical manifestations of cerebral palsy vary greatly in the type of movement disorder, the degree of functional ability and limitation and the affected parts of the body. There is currently no cure, but progress is being made in both the prevention and the amelioration of the brain injury. For example, administration of magnesium sulfate during premature labour and cooling of high-risk infants can reduce the rate and severity of cerebral palsy. Although the disorder affects individuals throughout their lifetime, most cerebral palsy research efforts and management strategies currently focus on the needs of children. Clinical management of children with cerebral palsy is directed towards maximizing function and participation in activities and minimizing the effects of the factors that can make the condition worse, such as epilepsy, feeding challenges, hip dislocation and scoliosis. These management strategies include enhancing neurological function during early development; managing medical co-morbidities, weakness and hypertonia; using rehabilitation technologies to enhance motor function; and preventing secondary musculoskeletal problems. Meeting the needs of people with cerebral palsy in resource-poor settings is particularly challenging.

Gabapentin can significantly improve dystonia severity and quality of life in children

INTRODUCTION

Gabapentin has been used in the management of neuropathic pain, epilepsy and occasionally movement disorders.

METHODS

A four-year retrospective, observational study analysed the use of gabapentin for severe dystonia in children at the Evelina London Children's Hospital. Motor severity was classified according to the Gross Motor Function Classification System (GMFCS), Dystonia Severity Assessment Plan (DSAP) and levels of impairment in activities of daily living were graded according to the WHO International Classification of Functioning, Disability and Health, Children & Youth version (ICF-CY) before and after gabapentin.

RESULTS

The majority of the 69 children reported were level 5 GMFCS (non-ambulant). The DSAP grade fell significantly from grade 3 before to grade 1 after gabapentin. Significant improvements in median ICF-CY grades were seen following gabapentin in sleep quality, sleep amount, mood & agreeableness, pain, general muscle tone, involuntary muscle contractions and seating tolerance (p < 0.01 in all areas). A significantly higher mean dose of 18.1 mg/kg/dose (SD: 13.3) for dystonia, compared to 7.61 mg/kg/dose (SD: 4.14) for pain relief without dystonia (z = -2.54, p = 0.011) was noted.

DISCUSSION & CONCLUSION

Gabapentin may significantly ameliorate dystonia severity and improve activities of daily living and quality of life in children with severe dystonia.