Hortensia Gimeno

Proportion of life lived with dystonia inversely correlates with response to pallidal deep brain stimulation in both primary and secondary childhood dystonia

The aim of this study was to examine the impact of dystonia aetiology and duration, contracture, and age at deep brain stimulation (DBS) surgery on outcome in a cohort of children with medically refractory, disabling primary, secondary‐static, or secondary‐progressive dystonias, including neurodegeneration with brain iron accumulation (NBIA).

Original articleBeyond the Burke–Fahn–Marsden Dystonia Rating Scale: Deep brain stimulation in childhood secondary dystonia

PURPOSE Deep brain stimulation is now widely accepted as an effective treatment for children with primary generalized dystonia. More variable results are reported in secondary dystonias and its efficacy in this heterogeneous group has not been fully elucidated. Deep brain stimulation outcomes are typically reported using impairment-focused measures, such as the Burke-Fahn-Marsden Dystonia Rating Scale, which provide little information about function and participation outcomes or changes in non-motor areas. The aim is to demonstrate that in some cases of secondary dystonia, the sole use of impairment level measures, such as the Burke-Fahn-Marsden Dystonia Rating Scale, may be insufficient to fully evaluate outcome following deep brain stimulation. METHODS Six paediatric cases who underwent deep brain stimulation surgery with a minimum of one year follow up were selected on the basis of apparent non-response to deep brain stimulation, defined as a clinically insignificant change in the Burke-Fahn-Marsden Dystonia Movement Scale (<20%), but where other evaluation measures demonstrated clinical efficacy across several domains. RESULTS Despite no significant change in Burke-Fahn-Marsden Dystonia Rating Scale scores following deep brain stimulation, parallel outcome measures demonstrated significant benefit in a range of child and family-centred goal areas including: pain and comfort, school attendance, seating tolerance, access to assistive technology and in some cases carer burden. CONCLUSIONS Sole use of impairment-focused measures, are limited in scope to evaluate outcome following deep brain stimulation, particularly in secondary dystonias. Systematic study of effects across multiple dimensions of disability is needed to determine what deep brain stimulation offers patients in terms of function, participation, care, comfort and quality of life. Deep brain stimulation may offer meaningful change across multiple domains of functioning, disability and health even in the absence of significant change in dystonia rating scales.

The impact and prognosis for dystonia in childhood including dystonic cerebral palsy: a clinical and demographic tertiary cohort study

Introduction and methods The impact of dystonia in childhood is poorly understood. We report our experience of referrals between 2005 and 2012. Results Of 294/315 assessable children, 15/294 had pure spasticity, leaving 279/294 with dystonia classified as primary (30/279: 10.7%); primary-plus (19/279: 6.8%) and secondary (230/279: 82.4%) dystonia, including heredodegenerative dystonia (29/279: 10.3%); 150/279 (53.7%) with cerebral palsy and 51/279 (18.2%) acquired brain injury. Definitive diagnoses were available in 222/294 (79.6%), but lower in primary/primary-plus compared with secondary groups (11/49 vs 211/230: Fishers exact test p<0.0001). Spasticity comorbidity was present in 79/230 (34.3%) children. Median age (interquartile years) at referral was 9.75 (6.58–13), not significantly differing by aetiology (Kruskal–Wallis test p>0.05); dystonia-onset age was 3 (0.5–7.0) for primary/primary-plus and 0.25 (0.08–0.8) in the secondary/CP groups. Dystonia duration at referral was 4.75 years (3.0–10.33) for primary/primary-plus groups and 7.83 (5.4–11) in the secondary group. The mean (interquartile range) proportion of life lived with dystonia, derived as dystonia duration normalised to age was 0.68 (0.31–0.96); 0.59 (0.35–0.8); 0.75 (0.62–0.95)and 0.9 (0.92–0.99) for primary, primary-plus, heredodegenerative and secondary-static dystonias respectively. Only 91/279 (32.6%) experienced a period of normal motor development. Carers perceived dystonia deterioration in 168/279 (60.2%), stabilisation in 88/279 (31.5%) and improvement in 23/279 (8.2%). Dystonia occurred in 26/225 (11.6%) siblings: 14/26 secondary and 5/26 heredodegenerative dystonia. Comorbidities were identified in 176/279 (63.1%) cases. Gross Motor Function Classification System (GMFCS) levels I–III were commoner in primary/primary-plus (37/49: 75%) compared with secondary/CP (29/230: 13%) cases, χ2 p<0.0001). Discussion In this selective cohort, childhood dystonia is severe, presenting early before worsening without remission. Secondary dystonias spend a higher proportion of life living with dystonia and lower functional capacity. Despite referral bias, services offering neurosurgical interventions and health service planning agencies should understand the context and predicament of life with childhood dystonia.

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

AIMS This study aimed to determine the main concerns/priorities of the parents and carers of children with dystonia referred to our service and whether medical interventional studies addressed these concerns. METHODS Records of children assessed by our service from June 2005-December 2012 were reviewed and expressed parental/carer concerns at initial assessment categorized using the International Classification of Functioning (ICF) Framework. Medline, CINAHL and Embase databases were searched for outcome measures of medical and surgical interventional studies in childhood dystonia. RESULTS Data was collected from 273 children and young people with dystonia. The most commonly expressed concerns were: pain (104/273, 38.1%); difficulties in delivering activities of daily-living (66/273, 24.2%), difficulties with hand-use (59/273, 21.6%) and seating (41/273, 15.0%). Literature review identified 70 interventional studies, 46 neurosurgical and 24 pharmacological. The majority of neurosurgical studies (34/46) used impairment scales to measure change, with pharmacological studies typically reporting more subjective changes in motor symptoms. Only a minority of studies used assessments or scales capable of objectively addressing the concerns reported by our cohort. INTERPRETATIONS Existing interventional studies in childhood dystonia poorly address the main concerns of children with dystonia and their carers, limiting the conclusions which may be drawn as to true impact of these interventions in childhood.

Functional priorities in daily life for children and young people with dystonic movement disorders and their families

PURPOSE This study aims to describe the most prevalent functional concerns of a group of young people with dystonia and their primary carers, and to explore the relationship between concerns, aetiology, severity of motor disability and manual ability. METHOD The Canadian Occupational Performance Measure (COPM) was completed with 57 children with dystonic movement disorders (65% males/35% females, mean 11.2 years (3.5-18.1)): 25% had primary dystonia, 75% secondary dystonia. Gross motor and manual function were classified using the Gross Motor Function Classification System (GMFCS) and the Manual Ability Classification System (MACS). COPM concerns were analysed with respect to aetiology and severity of motor disability. RESULTS Almost three quarters of the respondents were GMFCS/MACS IV-V. All respondents had at least one concern around self-care. Other concerns included access to assistive technology, pain, dressing activities, use of tools and social participation. The nature and presence of concerns did not statistically differ according to the severity of gross motor or manual function impairment, though qualitative differences were noted. No statistical difference was found in relation to aetiology. INTERPRETATION Children and young people with dystonia have common functional concerns and priorities independent of the cause of dystonia, gross motor severity or manual function ability.

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

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.

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 Childrens Hospital and Kings 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.

Improvement in upper limb function in children with dystonia following deep brain stimulation

BACKGROUND Childhood dystonia can severely impact upper limb function. Deep brain stimulation (DBS) has been shown to be effective in reducing dystonic symptoms in childhood. Functional recovery following DBS is however not well understood. AIMS To explore changes in upper limb function following DBS in paediatric dystonia. METHODS Upper limb outcomes, using the Melbourne Assessment of Unilateral Upper Limb Function, are reported in 20 cases of childhood dystonia (unilateral n = 1, four limb n = 19) at 6 and 12 months following DBS. RESULTS Improvement in at least in one upper limb was seen in the majority of cases (n = 17, 85%) at 12 months following DBS. Deterioration of scores in both upper limbs was seen in 3 children with progressive disorders. Grouping the children aetiologically, a significant improvement in the dominant hand was obtained for the primary dystonia/dystonia-plus group at both six (p = 0.018) and twelve months (p = 0.012). In secondary dystonia due to a static disorder, improvement was also seen at 6 (p = 0.043) and 12 months (p = 0.046) in the non-dominant hand. No significant change was found in the group of children with progressive disorders. CONCLUSIONS DBS has the potential to alter upper limb function in children with primary and secondary dystonia. The dominant hand improved most in children with primary dystonias, with greater improvement in the non-dominant hand in secondary-static cases.

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.

Cognitive function in children with primary dystonia before and after deep brain stimulation

BACKGROUND Dystonia is characterised by involuntary movements (twisting, writhing and jerking) and postures. The effects of deep brain stimulation (DBS) surgery on the motor aspect of primary dystonias have been well reported, however, there is a paucity of research investigating its impact on cognitive function, particularly in childhood dystonia. We performed a follow-up of cognitive function in children with primary dystonia following DBS pallidal surgery. METHODS Cognitive function was measured in a cohort of 13 children with primary or primary plus dystonia who had undergone DBS surgery using a retrospective case series design. Baseline pre-DBS neuropsychological measures were compared to scores obtained at least one year following DBS. Cognitive function was assessed using standardised measures of intellectual ability and memory. RESULTS All children demonstrated improvements with regard to dystonia reduction, as measured by the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS). Overall, cognition remained stable following DBS in the majority of the cohort. Individual case analysis revealed improvements in some domains of cognitive function in eight members of the cohort and a deterioration of certain domains in four. CONCLUSION Cognition largely remained stable in children with primary/primary plus dystonia following DBS surgery, although further research with a larger sample is necessary to explore this statistically. Notwithstanding the limitations of a small size, this preliminary data has potentially positive implications for the impact of DBS on cognitive functioning within a paediatric population.