Top 10 Research Themes for Dystonia in Cerebral Palsy: A Community-Driven Research Agenda

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.

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.

Cerebral palsy registers around the world: A survey

AIM

To provide a description of cerebral palsy (CP) registers globally, identify which aim to report on CP epidemiology, and report similarities and differences across topics of importance for the sustainability and collaboration between registers.

METHOD

Representatives of all known CP registers globally (n = 57) were invited to participate. The online survey included 68 questions across aims, methodologies, output/impact, and stakeholder involvement. Responses were analysed using descriptive statistics.

RESULTS

Forty-five registers participated, including three register networks. Twenty were newly established or under development, including 12 in low- and middle-income countries (LMICs). An epidemiological aim was reported by 91% of registers. Funding is received by 85% of registers, most often from not-for-profit organizations. CP definitions are comparable across registers. While the minimum data set of a register network is used by most registers, only 25% of identified items are collected by all three register networks. Ninety per cent of registers measure research activities/output, and 64% measure research impact. People with lived experience are involved in 62% of registers.

INTERPRETATION

There has been a recent surge in CP registers globally, particularly in LMICs, which will improve understanding of CP epidemiology. Ongoing efforts to address identified methodological differences are essential to validate comparison of results and support register collaboration.

WHAT THIS PAPER ADDS

Cerebral palsy (CP) registers represent an increasing number of regions, including low- and middle-income, worldwide. Most registers collect the minimum data set of a CP register network. Research activities/output and impact are measured by most registers. The majority of registers involve people with lived experience in operation or research.

A strategic neurological research agenda for Europe: Towards clinically relevant and patient-centred neurological research priorities

BACKGROUND AND PURPOSE

Neurological disorders constitute a significant portion of the global disease burden, affecting >30% of the world's population. This prevalence poses a substantial threat to global health in the foreseeable future. A lack of awareness regarding this high burden of neurological diseases has led to their underrecognition, underappreciation, and insufficient funding. Establishing a strategic and comprehensive research agenda for brain-related studies is a crucial step towards aligning research objectives among all pertinent stakeholders and fostering greater societal awareness.

METHODS

A scoping literature review was undertaken by a working group from the European Academy of Neurology (EAN) to identify any existing research agendas relevant to neurology. Additionally, a specialized survey was conducted among all EAN scientific panels, including neurologists and patients, inquiring about their perspectives on the current research priorities and gaps in neurology.

RESULTS

The review revealed the absence of a unified, overarching brain research agenda. Existing research agendas predominantly focus on specialized topics within neurology, resulting in an imbalance in the number of agendas across subspecialties. The survey indicated a prioritization of neurological disorders and research gaps.

CONCLUSIONS

Building upon the findings from the review and survey, key components for a strategic and comprehensive neurological research agenda in Europe were delineated. This research agenda serves as a valuable prioritization tool for neuroscientific researchers, as well as for clinicians, donors, and funding agencies in the field of neurology. It offers essential guidance for creating a roadmap for research and clinical advancement, ultimately leading to heightened awareness and reduced burden of neurological disorders.

Os odontoideum and craniovertebral junction instability secondary to dystonia: case series and review of the literature

INTRODUCTION

Os odontoideum refers to a rounded ossicle detached from a hypoplastic odontoid process at the body of the axis. The aetiology has been debated and believed to be either congenital or acquired (resulting from trauma). Os odontoideum results in incompetence of the transverse ligament and thus predisposes to atlantoaxial instability and spinal cord injury.

METHODS/RESULTS

Three cases of children with severe dystonic cerebral palsy presenting with myelopathic deterioration secondary to atlantoaxial instability due to os odontoideum are presented. This observation supports the hypothesis of os odontoideum being an acquired phenomenon, secondary to chronic excessive movement with damage to the developing odontoid process.

CONCLUSION

In children with cerebral palsy and dystonia, pre-existing motor deficits may conceal an evolving myelopathy and result in delayed diagnosis of clinically significant atlantoaxial subluxation.

Physician Approaches to the Pharmacologic Treatment of Dystonia in Cerebral Palsy

Objective

To determine how physicians approach pharmacologic dystonia treatment in people with CP and assess physician readiness to participate in a randomized trial comparing existing pharmacologic dystonia treatments.

Methods

We administered a REDCap survey to physician members of the American Academy of Cerebral Palsy and Developmental Medicine and of the Child Neurology Society to assess which pharmacologic agents they use to treat dystonia in CP and their preferred indications and dosing.

Results

Of 479 physicians surveyed, 240 (50%) responded. Respondents treated functionally limiting (95%) and generalized (57%) dystonia and most commonly used six medications: baclofen (95%), trihexyphenidyl (79%), gabapentin (67%), carbidopa/levodopa (55%), clonazepam (55%), and diazepam (54%). Baclofen was preferred in people with co-existing spasticity (81%), gabapentin was preferred in people with co-existing pain (49%), and trihexyphenidyl was avoided in people with constipation (34%) or urinary retention (42%). Preferred dosing regimens followed published regimens for dystonia, when available, but otherwise followed published regimens for other CP symptoms (spasticity and seizures). Baclofen was preferred by 64% of respondents as first line treatment, but there was no clear consensus on second or third-line medications. Most respondents (51%) were comfortable randomizing their patients to receive any of the six most commonly used medications used to treat dystonia in CP.

Conclusions

This study summarizes current indications and dosing for the six most commonly used medications to treat dystonia in CP as per treating physicians in the US and Canada and also demonstrates physician support for a randomized trial comparing the effectiveness of these treatments.

Caregiver descriptions of dystonia in cerebral palsy

OBJECTIVE

To determine how caregivers describe dystonia in people with cerebral palsy (CP).

METHODS

In this prospective cohort study, paper surveys were administered to caregivers between September 7, 2021 and October 28, 2021 during CP Center visits at a large tertiary care center. Caregivers were asked to describe involuntary movements triggered by voluntary movement or triggered by tactile stimulation in the people with CP they cared for. Their CP Center medical provider separately assessed people with CP for dystonia. Movement features described exclusively by caregivers of people with CP and dystonia were determined using conventional content analysis.

RESULTS

113 caregivers responded on behalf of 56 people with and 57 people without dystonia. If caregivers noted that both voluntary movement and tactile stimulation triggered involuntary movements, that had a 92% positive predictive value for a dystonia diagnosis. Movement features exclusively described in people with CP and dystonia included: (1) stiffening, tensing, or tightening (15% of respondents); (2) involvement of the head (10%), torso (5%), or feet (5%); and (3) triggers of stretching (12.5%), excitement (5%), or transfers (5%).

INTERPRETATION

In addition to a thorough exam, asking caregivers of people with CP to describe involuntary movements triggered by voluntary movement or tactile stimulation may inform clinical dystonia diagnosis.

The critical need to accelerate cerebral palsy research with consumer engagement, global networks, and adaptive designs

The prevalence of cerebral palsy (CP) varies globally, with higher rates and burden of disease in low- and middle-income countries. CP is a lifelong condition with no cure, presenting diverse challenges such as motor impairment, epilepsy, and mental health disorders. Research progress has been made but more is needed, especially given consumer demands for faster advancements and improvements in the scientific evidence base for interventions. This paper explores three strategies to accelerate CP research: consumer engagement, global clinical trial networks, and adaptive designs. Consumer engagement involving individuals with lived experience enhances research outcomes. Global clinical trial networks provide efficiency through larger and more diverse participant pools. Adaptive designs, unlike traditional randomized controlled trials, allow real-time modifications based on interim analyses, potentially answering complex questions more efficiently. The establishment of a CP Global Clinical Trials Network, integrating consumer engagement, global collaboration, and adaptive designs, marks a paradigm shift. The Network aims to address consumer-set research priorities. While challenges like ethical considerations and capacity building exist, the potential benefits for consumers, clinicians, researchers, and funding bodies are substantial. This paper underscores the urgency of transforming CP research methodologies for quicker translation of novel treatments into clinical practice to improve quality of life for those with CP.

Brain Region Size Differences Associated With Dystonia in People With Cerebral Palsy Born Premature

BACKGROUND

Dystonia in cerebral palsy (CP) is classically associated with deep gray matter injury at term gestation, but the patterns of injury associated with dystonia following premature birth are unclear. We examined whether there were brain regional size differences associated with dystonia in people with CP born premature.

METHODS

In this retrospective cohort study, we identified subjects with CP born premature (<37 weeks gestational age) seen at a tertiary care CP center between February 1, 2017, to February 1, 2021, who had T1-weighted brain magnetic resonance imaging (MRI) done between ages one and five years available in the clinical record. We measured the following on these brain MRI images per the 2013 Kidokoro criteria: interhemispheric distance, biparietal width, lateral ventricle diameter, transcerebellar diameter, deep gray matter area, and corpus callosum thickness. We then compared the sizes of these structures between those with and without dystonia correcting for gestational age at birth and gross motor functional ability (univariate general linear models).

RESULTS

Fifty-five subjects met the inclusion and exclusion criteria. Interhemispheric distance was significantly greater in those with dystonia, suggesting decreased cortical volume (P = 0.005). There was no significant difference in the other measured structures between those with and without dystonia, including deep gray matter area.

CONCLUSIONS

Increased interhemispheric distance, not measures of deep gray matter size, correlate with the presence of dystonia in people with CP born premature.

Identifying Effective Treatments for Dystonia in Patients With Cerebral Palsy: A Precision Therapeutics Approach

Recent focus on improving the recognition of dystonia in cerebral palsy (DCP) has highlighted the need for more effective treatments. Evidence supports improved functional outcomes with early interventions for patients with cerebral palsy, but it is not known which interventions are most effective for DCP. Current pharmacologic recommendations for DCP are based largely on anecdotal evidence, with medications demonstrating minimal to moderate improvements in dystonia and variable efficacy between patients. Patients, families, and clinicians have identified the need for new and improved treatments in DCP, naming this as the top research theme in a recent Neurology® publication. Precision therapeutics focuses on providing early effective interventions that are individualized to every patient and can guide research priorities to improve treatments for DCP. This commentary outlines current obstacles to improving treatment of DCP and addresses how precision therapeutics can address each of these obstacles through 4 key components: (1) identification of predictive biomarkers to select patients likely to develop DCP in the future and for whom early intervention may be appropriate to delay or prevent full manifestation of dystonia, (2) stratification of patients with DCP into subgroups according to shared features (clinical, functional, biochemical, etc) to provide a targeted intervention based on those shared features, (3) administration of an individualized dose of an effective intervention to ensure adequate concentrations of the therapeutic entity at the site of action, and (4) monitoring of objective biomarkers of response to intervention. With implementation of each of these components of precision therapeutics, new and more effective treatments for every person with DCP can be realized.

Determinants of gait dystonia severity in cerebral palsy

AIM

To determine the movement features governing expert assessment of gait dystonia severity in individuals with cerebral palsy (CP).

METHOD

In this prospective cohort study, three movement disorder neurologists graded lower extremity dystonia severity in gait videos of individuals with CP using a 10-point Likert-like scale. Using conventional content analysis, we determined the features experts cited when grading dystonia severity. Then, using open-source pose estimation techniques, we determined gait variable analogs of these expert-cited features correlating with their assessments of dystonia severity.

RESULTS

Experts assessed videos from 116 participants (46 with dystonia aged 15 years [SD 3] and 70 without dystonia aged 15 years [SD 2], both groups ranging 10-20 years old and 50% male). Variable limb adduction was most commonly cited by experts when identifying dystonia, comprising 60% of expert statements. Effect on gait (regularity, stability, trajectory, speed) and dystonia amplitude were common features experts used to determine dystonia severity, comprising 19% and 13% of statements respectively. Gait variables assessing adduction variability and amplitude (inter-ankle distance variance and foot adduction amplitude) were significantly correlated with expert assessment of dystonia severity (multiple linear regression, p < 0.001).

INTERPRETATION

Adduction variability and amplitude are quantifiable gait features that correlate with expert-determined gait dystonia severity in individuals with CP. Consideration of these features could help optimize and standardize the clinical assessment of gait dystonia severity in individuals with CP.