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

Neurosurgical management for chronic and end-of-life pain in children: A systematic review

INTRODUCTION

Chronic and end-of-life pain in children is underreported and undermanaged. Current guidelines for pediatric chronic pain include medical and interventional modalities; however, the inclusion of neurosurgical treatments is uncommon and inconsistent. This systematic review presents the literature, and we provide recommendations for the role of neurosurgical procedures in treating chronic and end-of-life pain in children.

METHODS

A systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Review and Meta-analyses (PRISMA) guidelines using three databases: PubMed, Embase, and Scopus. We included 40 studies presenting neurosurgical procedures for the treatment of chronic and end-of-life pain in children.

RESULTS

Thirty-one (77.5%) manuscripts focused on the treatment of neuropathic pain, five (12.5%) focused on nociceptive pain, and four (10%) treated mixed pain conditions. The most common neurosurgical procedure was intrathecal opioid therapy via pump placement (29.3%), followed by spinal cord stimulation (26.8%). Neuropathic pain syndromes were primarily treated with neurostimulation (58%), demonstrating good efficacy. Ablative procedures (40%) were most effective for nociceptive pain syndromes. Both chordotomy and intrathecal pumps provided subjective pain relief for mixed pain syndromes. The quantification of procedural efficacy, including pain outcomes and grading scales, varied significantly across studies.

CONCLUSION

Neurosurgical treatments for chronic pediatric pain are safe, although broad efficacy cannot be determined due to sparse literature and inadequately quantified pain responses. Guidelines for escalating chronic and end-of-life pain management in pediatric patients should be updated to include neurosurgical treatments and appropriate outcome scales. Focused research on appropriate patients, available neurosurgical therapies, and pediatric outcomes is warranted.

Towards new perspectives: International consensus guidance on dystonia in pediatric palliative care

BACKGROUND

Pediatric dystonias are associated with a broad spectrum of etiologies, resulting in a heterogeneous patient population in whom clinical presentation, evolution, and therapeutic needs may differ. These neurological symptoms are particularly common in children and adolescents with life-limiting and life-threatening conditions requiring pediatric palliative care (PPC). The impact on the child's quality of life is significant, as is distress for caregivers. Addressing and alleviating dystonia is key to providing good palliative care; however, there is limited evidence. A greater recognition and management of dystonia in this setting is urgently needed to provide appropriate interventions and care.

OBJECTIVES

To develop a standardized approach to dystonia in PPC.

MATERIALS AND METHODS

A two-round Delphi process explored the views of experts on the definition, assessment, monitoring, and treatment of dystonia in PPC. Professionals from different backgrounds and disciplines were invited worldwide. The final panel comprised 71 participants who completed a multi-statement online questionnaire.

RESULTS

Fifty-three items were endorsed, providing expert, consensus-based recommendations.

CONCLUSIONS

The limited clinical knowledge of childhood dystonia represents a challenge, especially in children with palliative care needs. This study is a first international consensus on dystonia in PPC and offers novel approaches to improving the dystonia-related burden and advancing clinical practice in this vulnerable population.

Impact of Spinal Deformity and Surgery on Health-Related Quality of Life in Cerebral Palsy: A Multicenter Prospective Controlled Trial

BACKGROUND

Spinal fusion for scoliosis associated with cerebral palsy (CP) is challenging to study because specialized outcome measures are needed. Therefore, evidence in favor of the benefits of surgery has not been firmly established. This study aimed to determine if corrective spinal fusion improves health-related quality of life (HRQoL) in children with CP scoliosis at 2 years.

METHODS

Children with CP and scoliosis who met the criteria for posterior spinal fusion were offered enrollment at 16 US and Canada centers. Participants' families selected either operative intervention (OP) or nonoperative treatment (NON) in discussion with their surgeon with no influence by the decision to participate in the research study. Demographic, clinical data (function level, magnitude of deformity, comorbidities), and HRQoL (CPCHILD Questionnaire) were collected at baseline and 2 years. Change (from baseline) in total CPCHIL scores was the primary outcome.

RESULTS

Three hundred one OP and 34 NON subjects had complete baseline and 2-year data. At baseline, both groups were comparable in function level, comorbid status, and CPCHILD scores (52.1 ±15.3 vs. 53.4 ±14.5; P =0.66). The OP group had a larger spinal deformity magnitude (84.5˚ ± 21.8˚ vs. 66.3˚ ± 18.1˚) ( P =0.001). The total CPCHILD score improved in the OP group by 6.6 points ( P <0.001). NON scores were unchanged (+1.2; P =0.65) during follow-up. There were also significant score increases in the OP group for 5 of 6 CPCHILD domains. The change in CPCHILD scores from enrollment to 2 years was more significant in the OP group ( P =0.05).

CONCLUSION

For children with CP who undergo spinal fusion, HRQoL improved over preoperative levels and an unchanged nonoperative control group.

LEVEL OF EVIDENCE

Level II.

Improving paediatric movement disorders care: Insights on rating scales utilization and clinical practice

AIM

This exploratory study evaluates rating scale usage by experts from the European Reference Network for Rare Neurological Diseases (ERN-RND) for paediatric MD, considering factors like diagnosis, intellectual disability, age, and transition to adult care. The aim is to propose a preliminary framework for consistent application.

METHODS

A multicentre survey among 25 ERN-RND experts from 10 European countries examined rating scale usage in paediatric MD, categorizing MD into acute, non-progressive, and neurodegenerative types. Factors influencing scale choice and the transition to adult care practices were analysed. A comprehensive literature search was conducted to identify the earliest age of application of these scales in paediatric patients.

RESULTS

The study identifies various rating scales and establishes their usage frequencies for different MDs. Experts highlighted the need for standardized scales and proposed preliminary evaluation strategies based on clinical contexts. Challenges in applying scales to young, non-cooperative patients were acknowledged.

INTERPRETATION

The study recommends developing standardized rating scales for paediatric MDs to improve evaluations and data collection. It suggests potential scales for specific clinical scenarios to better evaluate disease progression. Comprehensive, patient-centred care remains crucial during the transition to adult care, despite the identified challenges. This exploratory approach aims to enhance patient outcomes and care.

Efficacy of Oral Trihexyphenidyl Plus Clonazepam Versus Trihexyphenidyl for the Treatment of Dystonia in Children With Dystonic Cerebral Palsy: An Open-Label Randomized Controlled Trial

BACKGROUND

Trihexyphenidyl and clonazepam are commonly used to treat dystonia in children with cerebral palsy (CP). However, there is a notable gap in the literature when it comes to studies that combine these first-line agents for the management of dystonia.

METHODS

This open-label, randomized controlled trial aimed to compare the efficacy of adding oral clonazepam to trihexyphenidyl (THP + CLZ) versus using trihexyphenidyl alone (THP) in reducing the severity of dystonia, as measured by the Barry-Albright Dystonia (BAD) score. The study was conducted over a 12-week therapy period in children with dystonic CP aged two to 14 years.

RESULTS

Each group enrolled 51 participants. The THP + CLZ group showed significantly better improvement in dystonia severity at 12 weeks compared with the THP group alone (-4.5 ± 2.9 vs -3.4 ± 1.7, P = 0.02). Furthermore, the THP + CLZ group exhibited superior improvement in the severity of choreoathetosis, upper limb function, pain perception by the child, and quality of life, with P values of 0.02, 0.009, 0.01, and 0.01, respectively. The number of participants experiencing treatment-emergent adverse events was comparable in both groups (P = 0.67). Importantly, none of the participants in any of the groups reported any serious adverse events.

CONCLUSION

A combination of oral THP + CLZ proves to be more efficacious than using THP alone for the treatment of dystonic CP in children aged two to 14 years in terms of reducing the severity of dystonia.

Evolving understanding of CP phenotypes: the importance of dystonia

Cerebral palsy (CP) is the core neurodevelopmental disorder affecting movement. Several distinct movement disorders can occur in people with cerebral palsy. Dystonia is a movement disorder that causes non-velocity-dependent hypertonia and/or abnormal, often repetitive, twisting movements, and/or postures. Dystonia occurs more frequently in patients with CP than has been recognized previously, and is treated differently than other aspects of CP. Dystonia is an important cause of chronic pain, hospitalization, and musculoskeletal complications. We describe recent advances in dystonia diagnosis in patients with cerebral palsy and highlight focus areas for ongoing research and clinical care. IMPACT: Dystonia is a movement disorder that is more common in people with cerebral palsy (CP) than previously thought. Dystonia contributes to hospitalization, chronic pain, and complications in CP patients. People with dystonic CP require different tools to diagnose and treat their condition. We summarize current state of the art in dystonia in CP and identify areas of focus for future work.

Chronic pain in children and young people with cerebral palsy: a narrative review of challenges, advances, and future directions

BACKGROUND

Cerebral palsy (CP), the most common physical disability of childhood, is often accompanied by a range of comorbidities including pain. Pain is highly prevalent in children and young people with CP, yet has been poorly understood, inaccurately assessed, and inadequately managed in this vulnerable population. This narrative review presents recent research advances for understanding and managing pain in children and young people with CP, focusing on chronic pain, and highlights future research directions.

MAIN BODY

Pain prevalence rates in CP vary due to different methodologies of studies. Recent systematic reviews report up to 85% of children experience pain; higher in older children, females, and those with dyskinesia and greater motor impairment. Research examining the lived experience perspectives of children and their families demonstrate that even those with mild motor impairments have pain, children want to self-report pain where possible to feel heard and believed, and management approaches should be individualized. Notably, many children with cognitive and communication impairments can self-report their pain if adjustments are provided and they are given a chance. Past inadequacies of pain assessment in CP relate to a focus on pain intensity and frequency with little focus on pain interference and coping, a lack of tools appropriate for the CP population, and an assumption that many children with cognitive and/or communication limitations are unable to self-report. Recent systematic reviews have identified the most reliable and valid assessment tools for assessing chronic pain. Many were not developed for people with CP and, in their current form, are not appropriate for the spectrum of physical, communication, and cognitive limitations seen. Recently, consensus and co-design in partnership with people with lived experience and clinicians have identified tools appropriate for use in CP considering the biopsychosocial framework. Modifications to tools are underway to ensure feasibility and applicability for the spectrum of abilities seen.

CONCLUSION

Recent research advances have improved our understanding of the prevalence, characteristics and lived experience of chronic pain, and refined assessment methods in children and young people with CP. However, the very limited evidence for effective and novel management of chronic pain in this population is where research should now focus.

Les soins aux enfants et aux adolescents ayant la paralysie cérébrale (aux niveaux III à V du GMFCS)

La paralysie cérébrale (PC) est l'incapacité physique la plus fréquente chez les enfants canadiens. Les soins complets des enfants ayant la PC, qui sont capables de marcher et qui fonctionnent aux niveaux I et II du système de classification de la fonction motrice globale (GMFCS) sont déjà exposés dans un point de pratique. Le présent document complémentaire traite des soins aux enfants ayant la PC qui fonctionnent aux niveaux III à V du GMFCS. Ceux qui fonctionnent aux niveaux III et IV du GMFCS utilisent des dispositifs d'assistance comme des déambulateurs, des cannes ou des aides à la mobilité motorisées, tandis que ceux qui fonctionnent au niveau V du GMFCS ont besoin d'assistance à la mobilité comme un fauteuil roulant manuel. Le présent document contient un aperçu des principaux concepts relatifs à la détection précoce, aux services de réadaptation et aux possibilités de traitement pour les enfants présentant ces niveaux de PC, conjointement avec des ressources pratiques pour contribuer à la surveillance de la santé assurée par les pédiatres qui s'occupent de cette population.

Care for children and youth with cerebral palsy (GMFCS levels III to V)

Cerebral palsy (CP) is the most common physical disability in Canadian children. The comprehensive care of ambulatory children with CP functioning at Gross Motor Function Classification System (GMFCS) level I and II was covered in a previous practice point. This companion document focuses on the care of children with CP functioning at GMFCS levels III to V. Children functioning at GMFCS level III and IV mobilize using devices such as a walker, canes, or powered mobility, while those functioning at GMFCS level V require assisted mobility, such as a manual wheelchair. An overview of key concepts in early detection, rehabilitation services, and therapeutic options for children with CP at these levels is provided, along with practical resources to assist health surveillance for paediatricians caring for this population.

Quality of life outcomes after deep brain stimulation in acquired dystonia: a systematic review and meta-analysis

BACKGROUND

Dystonia is a condition that affects the ability to control the movement and function of the body's muscles. It can cause not only physical problems, but also mental problems, resulting in impaired health-related quality of life (HRQoL). However, the effect of deep brain stimulation on quality of life in acquired dystonia remains unclear.

METHODS

We conducted a systematic literature review from January 2000 to October 2022，determined the eligible studies, and performed a meta-analysis of HRQoL outcomes based on the Short-Form Health Survey-36 (SF-36) after DBS to evaluate the effects of DBS on physical and mental QoL.

RESULTS

A total of 14 studies met the inclusion criteria and were systematically reviewed. A comprehensive meta-analysis was performed for 9 studies that reported physical and psychological data or physical component summary (PCS), or mental component summary (MCS) for SF-36. The mean (SD) age at DBS implantation was 34.29 (10.3) years, and the follow-up period after implantation was 2.21 (2.80) years. The random effects model meta-analysis revealed that both physical and mental domains of the SF-36 improved following DBS. There was no statistically significant difference between the physical domains (effect size=1.34; p<0.0001) and the mental domains (effect size=1.38; p<0.0001).

CONCLUSION

This is the first meta-analysis that demonstrates significant benefits in HRQoL following DBS in patients with acquired dystonia. There were significant improvements in both physical QoL and mental QoL.

Deep brain stimulation for chronic pain: a systematic review and meta-analysis

Background

Deep brain stimulation (DBS) has shown promise in effectively treating chronic pain. This study aimed to assess the efficacy of DBS in this context.

Methods

We conducted a systematic literature search using PubMed, Scopus, and Web of Science, following the PRISMA guidelines. A well-constructed search strategy was utilized. Our literature search identified two groups of subjects: one group underwent DBS specifically for chronic pain treatment (DBS-P), while the second group received DBS for other indications (DBS-O), such as Parkinson's disease or dystonia, with pain perception investigated as a secondary outcome in this population. Meta-analysis was performed using R version 4.2.3 software. Heterogeneity was assessed using the tau^2 and I^2 indices, and Cochran's Q-test was conducted.

Results

The analysis included 966 patients in 43 original research studies with chronic pain who underwent DBS (340 for DBS-P and 625 for DBS-O). Subgroup analysis revealed that DBS-P exhibited a significant effect on chronic pain relief, with a standardized mean difference (SMD) of 1.65 and a 95% confidence interval (CI) of [1.31; 2.00]. Significant heterogeneity was observed among the studies, with an I^2 value of 85.8%. However, no significant difference was found between DBS-P and DBS-O subgroups. Subgroup analyses based on study design, age, pain diseases, and brain targets demonstrated varying levels of evidence for the effectiveness of DBS across different subgroups. Additionally, meta-regression analyses showed no significant relationship between age or pain duration and DBS effectiveness for chronic pain.

Conclusion

These findings significantly contribute to the expanding body of knowledge regarding the utility of DBS in the management of chronic pain. The study underscores the importance of conducting further research to enhance treatment outcomes and elucidate patient-specific factors that are associated with treatment response.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=428442, identifier CRD42023428442.

Recommendations for diagnosing and managing individuals with glutaric aciduria type 1: Third revision

Glutaric aciduria type 1 is a rare inherited neurometabolic disorder of lysine metabolism caused by pathogenic gene variations in GCDH (cytogenic location: 19p13.13), resulting in deficiency of mitochondrial glutaryl-CoA dehydrogenase (GCDH) and, consequently, accumulation of glutaric acid, 3-hydroxyglutaric acid, glutaconic acid and glutarylcarnitine detectable by gas chromatography/mass spectrometry (organic acids) and tandem mass spectrometry (acylcarnitines). Depending on residual GCDH activity, biochemical high and low excreting phenotypes have been defined. Most untreated individuals present with acute onset of striatal damage before age 3 (to 6) years, precipitated by infectious diseases, fever or surgery, resulting in irreversible, mostly dystonic movement disorder with limited life expectancy. In some patients, striatal damage develops insidiously. In recent years, the clinical phenotype has been extended by the finding of extrastriatal abnormalities and cognitive dysfunction, preferably in the high excreter group, as well as chronic kidney failure. Newborn screening is the prerequisite for pre-symptomatic start of metabolic treatment with low lysine diet, carnitine supplementation and intensified emergency treatment during catabolic episodes, which, in combination, have substantially improved neurologic outcome. In contrast, start of treatment after onset of symptoms cannot reverse existing motor dysfunction caused by striatal damage. Dietary treatment can be relaxed after the vulnerable period for striatal damage, that is, age 6 years. However, impact of dietary relaxation on long-term outcomes is still unclear. This third revision of evidence-based recommendations aims to re-evaluate previous recommendations (Boy et al., J Inherit Metab Dis, 2017;40(1):75-101; Kolker et al., J Inherit Metab Dis 2011;34(3):677-694; Kolker et al., J Inherit Metab Dis, 2007;30(1):5-22) and to implement new research findings on the evolving phenotypic diversity as well as the impact of non-interventional variables and treatment quality on clinical outcomes.

Deep Brain Stimulation for Pediatric Dystonia: A Review of the Literature and Suggested Programming Algorithm

Deep brain stimulation (DBS) is an established intervention for use in pediatric movement disorders, especially dystonia. Although multiple publications have provided guidelines for deep brain stimulation patient selection and programming in adults, there are no evidence-based or consensus statements published for pediatrics. The result is lack of standardized care and underutilization of this effective treatment. To this end, we assembled a focus group of 13 pediatric movement disorder specialists and 1 neurosurgeon experienced in pediatric deep brain stimulation to review recent literature and current practices and propose a standardized approach to candidate selection, implantation target site selection, and programming algorithms. For pediatric dystonia, we provide algorithms for (1) programming for initial session and follow-up sessions, and (2) troubleshooting side effects encountered during programming. We discuss common side effects, how they present, and recommendations for management. This topical review serves as a resource for movement disorders specialists interested in using deep brain stimulation for pediatric dystonia.

Mental health and behaviour in children with dystonia: Anxiety, challenging behaviour and the relationship to pain and self-esteem

PURPOSE

To ascertain whether young people with dystonia are more likely than the general population to have mental health and/or behavioural difficulties, and to explore factors that may contribute to these difficulties.

METHOD

Using a quasi-experimental design, 50 young people with dystonia aged 7-17 and their carers were recruited from the Evelina London Children's Hospital. Young people completed the Beck Youth Inventories and the Strengths and Difficulties Questionnaire. Carers completed the Strengths and Difficulties Questionnaire-Parent version and the Paediatric Pain Profile. Important medical factors, such as age of onset, motor severity and manual function were obtained from medical records.

RESULTS

One sample z tests showed young people with dystonia self-reported significantly higher levels of anxiety (p < .001) and prosocial difficulties (p < .01), with 48% experiencing clinically significant anxiety levels. They experienced significantly lower levels of anger, disruptive behaviour and conduct problems (all p ≤ .01). Carers reported significantly higher rates of emotional problems, hyperactivity and peer problems, and significantly lower prosocial behaviours (all p ≤ .01). Pearson's correlation coefficients showed lower levels of self-esteem were related to higher levels of anxiety (p = .015). High levels of pain were related to parent-rated conduct problems (p = .004). Age of dystonia onset and motor severity did not correlate with any of the psychological or behavioural measures.

INTERPRETATION/CONCLUSIONS

Our study suggests high rates of anxiety and behaviours that challenge in children with dystonia. Screening in movement clinics would be helpful in early identification and signposting for support.

Pharmacological and neurosurgical interventions for individuals with cerebral palsy and dystonia: a systematic review update and meta-analysis

AIM

To update a systematic review of evidence published up to December 2015 for pharmacological/neurosurgical interventions among individuals with cerebral palsy (CP) and dystonia.

METHOD

Searches were updated (January 2016 to May 2020) for oral baclofen, trihexyphenidyl, benzodiazepines, clonidine, gabapentin, levodopa, botulinum neurotoxin (BoNT), intrathecal baclofen (ITB), and deep brain stimulation (DBS), and from database inception for medical cannabis. Eligible studies included at least five individuals with CP and dystonia and reported on dystonia, goal achievement, motor function, pain/comfort, ease of caregiving, quality of life (QoL), or adverse events. Evidence certainty was evaluated using GRADE.

RESULTS

Nineteen new studies met inclusion criteria (two trihexyphenidyl, one clonidine, two BoNT, nine ITB, six DBS), giving a total of 46 studies (four randomized, 42 non-randomized) comprising 915 participants when combined with those from the original systematic review. Very low certainty evidence supported improved dystonia (clonidine, ITB, DBS) and goal achievement (clonidine, BoNT, ITB, DBS). Low to very low certainty evidence supported improved motor function (DBS), pain/comfort (clonidine, BoNT, ITB, DBS), ease of caregiving (clonidine, BoNT, ITB), and QoL (ITB, DBS). Trihexyphenidyl, clonidine, BoNT, ITB, and DBS may increase adverse events. No studies were identified for benzodiazepines, gabapentin, oral baclofen, and medical cannabis.

INTERPRETATION

Evidence evaluating the use of pharmacological and neurosurgical management options for individuals with CP and dystonia is limited to between low and very low certainty. What this paper adds Meta-analysis suggests that intrathecal baclofen (ITB) and deep brain stimulation (DBS) may improve dystonia and pain. Meta-analysis suggests that DBS may improve motor function. Clonidine, botulinum neurotoxin, ITB, and DBS may improve achievement of individualized goals. ITB and DBS may improve quality of life. No direct evidence is available for oral baclofen, benzodiazepines, gabapentin, or medical cannabis.

Deep Brain Stimulation for Pediatric Dystonia

Dystonia is one of the most common pediatric movement disorders and can have a profound impact on the lives of children and their caregivers. Response to pharmacologic treatment is often unsatisfactory. Deep brain stimulation (DBS) has emerged as a promising treatment option for children with medically refractory dystonia. In this review we highlight the relevant literature related to DBS for pediatric dystonia, with emphasis on the background, indications, prognostic factors, challenges, and future directions of pediatric DBS.

Deep Brain Stimulation and Hypoxemic Perinatal Encephalopathy: State of Art and Perspectives

Cerebral palsy (CP) is a heterogeneous group of non-progressive syndromes with lots of clinical variations due to the extent of brain damages and etiologies. CP is majorly defined by dystonia and spasticity. The treatment of acquired dystonia in CP is very difficult. Many pharmacological treatments have been tried and surgical treatment consists of deep brain stimulation (continuous electrical neuromodulation) of internal globus pallidus (GPi). A peculiar cause of CP is neonatal encephalopathy due to an anoxic event in the perinatal period. Many studies showed an improvement of dystonia in CP patients with bilateral GPi DBS. However, it remains a variability in the range of 1% to 50%. Published case-series concerned mainly small population with a majority of adult patients. Selection of patients according to the clinical pattern, to the brain lesions observed on classical imaging and to DTI is the key of a high success rate of DBS in children with perinatal hypoxemic encephalopathy. Only a large retrospective study with a high number of patients in a homogeneous pediatric population with a long-term follow-up or a prospective multicenter trial investigation could answer with a high degree of certitude of the real interest of this therapeutic in children with hypoxemic perinatal encephalopathy.

Treatment of Disorders of Tone and Other Considerations in Pediatric Movement Disorders

Pediatric movement disorders (PMDs) consist of a heterogeneous group of signs and symptoms caused by numerous neurological diseases. Different neurological disorders in children also share overlapping movement disorders making a diagnosis of the underlying cause of the movement disorder challenging. The similarity of the symptoms across multiple disease types suggests that there may be a final common motor pathway causing the overlapping movement disorders. There are numerous disorders in children associated with disturbances in tone and involuntary movements. This chapter will focus primarily on those disorders that involve abnormalities of tone and other important considerations of pediatric movement disorders. This chapter will address rating scales and goals for treatment and will include a review of symptomatic treatment and, where possible, the treatment of the underlying disease processes. The chapter will review representative disorders, including an inborn error of metabolism, an autoimmune disorder, and a group of neurodegenerative disorders. These examples demonstrate how the disorder's underlying pathophysiology results in a specific approach to the underlying disease and the associated conditions of tone and involuntary movements. Finally, the multiple treatment options for cerebral palsy and considerations of cerebral palsy mimics will be discussed.

Application of Machine Learning Using Decision Trees for Prognosis of Deep Brain Stimulation of Globus Pallidus Internus for Children With Dystonia

BACKGROUND

While Deep Brain Stimulation (DBS) of the Globus pallidus internus is a well-established therapy for idiopathic/genetic dystonia, benefits for acquired dystonia are varied, ranging from modest improvement to deterioration. Predictive biomarkers to aid DBS prognosis for children are lacking, especially in acquired dystonias, such as dystonic Cerebral Palsy. We explored the potential role of machine learning techniques to identify parameters that could help predict DBS outcome.

METHODS

We conducted a retrospective study of 244 children attending King's College Hospital between September 2007 and June 2018 for neurophysiological tests as part of their assessment for possible DBS at Evelina London Children's Hospital. For the 133 individuals who underwent DBS and had 1-year outcome data available, we assessed the potential predictive value of six patient parameters: sex, etiology (including cerebral palsy), baseline severity (Burke-Fahn-Marsden Dystonia Rating Scale-motor score), cranial MRI and two neurophysiological tests, Central Motor Conduction Time (CMCT) and Somatosensory Evoked Potential (SEP). We applied machine learning analysis to determine the best combination of these features to aid DBS prognosis. We developed a classification algorithm based on Decision Trees (DTs) with k-fold cross validation for independent testing. We analyzed all possible combinations of the six features and focused on acquired dystonias.

RESULTS

Several trees resulted in better accuracy than the majority class classifier. However, the two features that consistently appeared in top 10 DTs were CMCT and baseline dystonia severity. A decision tree based on CMCT and baseline severity provided a range of sensitivity and specificity, depending on the threshold chosen for baseline dystonia severity. In situations where CMCT was not available, a DT using SEP alone provided better than the majority class classifier accuracy.

CONCLUSION

The results suggest that neurophysiological parameters can help predict DBS outcomes, and DTs provide a data-driven, highly interpretable decision support tool that lends itself to being used in clinical practice to help predict potential benefit of DBS in dystonic children. Our results encourage the introduction of neurophysiological parameters in assessment pathways, and data collection to facilitate multi-center evaluation and validation of these potential predictive markers and of the illustrative decision support tools presented here.