Fractional anisotropy in children with dystonia or spasticity correlates with the selection for DBS or ITB movement disorder surgery

Elective and Emergency Deep Brain Stimulation in Refractory Pediatric Monogenetic Movement Disorders Presenting with Dystonia: Current Practice Illustrated by Two Cases

BACKGROUND

Dystonia is characterized by sustained or intermittent muscle contractions, leading to abnormal posturing and twisting movements. In pediatric patients, dystonia often negatively influences quality of life. Pharmacological treatment for dystonia is often inadequate and causes adverse effects. Deep brain stimulation (DBS) appears to be a valid therapeutic option for pharmacoresistant dystonia in children.

METHODS

To illustrate the current clinical practice, we hereby describe two pediatric cases of monogenetic movement disorders presenting with dystonia and treated with DBS. We provide a literature review of similar previously described cases and on different clinical aspects of DBS in pediatric dystonia.

RESULTS

The first patient, a 6-year-old girl with severe dystonia, chorea, and myoclonus due to an ADCY5 gene mutation, received DBS in an elective setting. The second patient, an 8-year-old boy with GNAO1-related dystonia and chorea, underwent emergency DBS due to a pharmacoresistant status dystonicus. A significant amelioration of motor symptoms (65% on the Burke-Fahn-Marsden Dystonia Rating Scale) was observed postoperatively in the first patient and her personal therapeutic goals were achieved. DBS was previously reported in five patients with ADCY5-related movement disorders, of which three showed objective improvement. Emergency DBS in our second patient resulted in the successful termination of his GNAO1-related status dystonicus, this being the eighth case reported in the literature.

CONCLUSION

DBS can be effective in monogenetic pediatric dystonia and should be considered early in the disease course. To better evaluate the effects of DBS on patients' functioning, patient-centered therapeutic goals should be discussed in a multidisciplinary approach.

Deep brain stimulation of fornix for memory improvement in Alzheimer's disease: A critical review

Memory reflects the brain function in encoding, storage and retrieval of the data or information, which is a fundamental ability for any live organism. The development of approaches to improve memory attracts much attention due to the underlying mechanistic insight and therapeutic potential to treat neurodegenerative diseases with memory loss, such as Alzheimer's disease (AD). Deep brain stimulation (DBS), a reversible, adjustable, and non-ablative therapy, has been shown to be safe and effective in many clinical trials for neurodegenerative and neuropsychiatric disorders. Among all potential regions with access to invasive electrodes, fornix is considered as it is the major afferent and efferent connection of the hippocampus known to be closely associated with learning and memory. Indeed, clinical trials have demonstrated that fornix DBS globally improved cognitive function in a subset of patients with AD, indicating fornix can serve as a potential target for neurosurgical intervention in treating memory impairment in AD. The present review aims to provide a better understanding of recent progresses in the application of fornix DBS for ameliorating memory impairments in AD patients.

Starting a DBS service for children: It's not the latitude but the attitude - Establishment of the paediatric DBS centre in Northern Finland

OBJECTIVE

Paediatric movement disorder patients can benefit from deep brain stimulation (DBS) treatment and it should be offered in a timely manner. In this paper we describe our experience establishing a DBS service for paediatric patients.

METHODS

We set out to establish a paediatric DBS (pDBS) procedure in Oulu University Hospital in northern Finland, where up to this point DBS treatment for movement disorders had been available for adult patients. Collaboration with experienced centres aided in the process.

RESULTS

A multidisciplinary team was assembled and a systematic protocol for patient evaluation and treatment was created, with attention to special features of the regional health care system. All of our first paediatric patients had very severe movement disorders, which is typical for a new DBS centre. The patients benefitted from pDBS treatment despite variable aetiologies of movement disorders, which included cerebral palsy and rare genetic disorders with variants in PDE10A, TPK1 and ARX. We also present our high-quality paediatric MR-imaging protocol with tractography.

CONCLUSIONS

Establishment of a pDBS centre requires expertise in classification of paediatric movement disorders, longstanding experience in adult DBS and a committed multidisciplinary team. Besides high-quality imaging and a skilled neurosurgery team, careful patient selection, realistic treatment goals and experience in rehabilitation are imperative in pDBS treatment.

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.

Intrathecal baclofen, selective dorsal rhizotomy, and extracorporeal shockwave therapy for the treatment of spasticity in cerebral palsy: a systematic review

Cerebral palsy (CP) is a chronic congenital disorder as the result of abnormal brain development. Children suffering from CP often battle debilitating chronic spasticity, which has been the focus of recent academic literature. In this systematic review, the authors aim to update the current neuromodulation procedures for the treatment of spasticity associated with CP in all age groups. A systematic review following was conducted using PubMed from inception to 2020. After initial title and abstract screening, 489 articles were identified, and 48 studies met the inclusion criteria for this review. In total, a majority of the published articles of treatments for CP were reporting the use of selective dorsal rhizotomy (SDR) (54%), and the remainder were of intrathecal baclofen (ITB) pumps (29%) and extracorporeal shockwave therapy (ESWT) (17%). Each method was found to have improvement of spasticity at a rate that achieved statistical significance. ITB pump therapy is an all-encompassing method of treating spasticity in children from CP, as it allows for a less invasive treatment that can be titrated to individual patient needs; however, its disadvantages include its long-term maintenance requirements. SDR appears to be an effective method for permanent spasticity relief in young patients. ESWT is a more recent and innovative technique for offering relief of spasticity while being minimally invasiveness. Further studies are needed to establish optimal frequencies and sites of application for ESWT.

Cervical Dystonia Is Associated With Aberrant Inhibitory Signaling Within the Thalamus

Objective: The objective of this study is to investigate whether alterations in the neurotransmission of gamma-aminobutyric acid (GABA) in the thalamus are present in patients with cervical dystonia compared to healthy controls.

Methods: GABA magnetic resonance spectroscopy was used to investigate concentration levels of GABA in the thalamus of cervical dystonia patients (n = 17) compared to healthy controls (n = 18). Additionally, a focused post hoc analysis of thalamic GABA_A receptor availability data in a similar cohort (n = 15 for both groups) using data from a previously collected ¹¹C-flumazenil positron emission tomography study was performed. Group comparisons for all evaluations were performed using two-sided t-tests with adjustments for age and sex, and Bonferroni correction for multiple comparisons was applied. Spearman's coefficient was used to test correlations.

Results: We found significantly reduced GABA+/Cre levels in the thalamus of cervical dystonia patients compared to controls, and these levels positively correlated with disease duration. Although mean thalamic GABA_A receptor availability did not differ between patients and controls, GABA_A availability negatively correlated with both disease duration and dystonia severity.

Conclusions: These findings support that aberrant inhibitory signaling within the thalamus contributes to the pathophysiology of cervical dystonia. Additionally, these results suggest that an inadequate ability to compensate for the loss of GABA through upregulation of GABA_A receptors may underlie more severe symptoms.

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.

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.

Tensor and non-tensor tractography for the assessment of the corticospinal tract of children with motor disorders: a comparative study

INTRODUCTION

Non-invasive measures of corticospinal tract (CST) integrity may help to guide clinical interventions, particularly in children and young people (CAYP) with motor disorders. We compared diffusion tensor imaging (DTI) metrics extracted from the CST generated by tensor and non-tensor based tractography algorithms.

METHODS

For a group of 25 CAYP undergoing clinical evaluation, the CST was reconstructed using (1) deterministic tensor-based tractography algorithm, (2) probabilistic tensor-based, and (3) constrained spherical deconvolution (CSD)-derived tractography algorithms.

RESULTS

Choice of tractography algorithm significantly altered the results of tracking. Larger tracts were consistently defined with CSD, with differences in FA but not MD values for tracts to the pre- or post-central gyrus. Differences between deterministic and probabilistic tensor-based algorithms were minimal. Non-tensor reconstructed tracts appeared to be more anatomically representative. Examining metrics along the tract, difference in FA values appeared to be greatest in voxels with predominantly single-fibre orientations. Less pronounced differences were seen outwith of these regions.

CONCLUSION

With an increasing interest in the applications of tractography analysis at all stages of movement disorder surgery, it is important that clinicians remain alert to the consequences of choice of tractography algorithm on subsequently generated tracts, including differences in volumes, anatomical reconstruction, and DTI metrics, the latter of which will have global as well as more regional effects. Tract-wide analysis of DTI based metrics is of limited utility, and a more segmental approach to analysis may be appropriate, particularly if disruption to a focal region of a white matter pathway is anticipated.