Ataxia rating scales are age-dependent in healthy children

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.

Ataxia Rating Scales Reveal Increased Scores in Very Preterm Born 5-6-Year-Old Preschool Children and Young Adults

The aim of this study is to investigate whether scores in ataxia rating scales (ARS) are different in very preterm (VP) preschool and adult participants compared to term controls. This is a case-control study. Sixty VP children (years: 5.5-6.5; gestational age: 23.9-31.7 weeks) and 56 VP adults (years: 17.8-27.9; gestational age: 23.3-32.0 weeks) without major cerebral lesions participated in the study; 60-age and sex-matched term children and 64 term adults for comparison were used in the study intervened with the assessment with International Cooperative Ataxia Rating Scale (ICARS) and Scale for Assessment and Rating of Ataxia (SARA). Main outcome measures are primary outcome: total icars and sara scores in preterm (vp) participants versus controls. Results showed that VP children showed significantly higher total ICARS (M 15.98, SD 6.29, range 4.0-32.0; p < .001) and SARA scores (M 6.5, SD 2.53, range 1.0-15.0; p < .001) than controls (ICARS: M 9.17, SD 3.88, range 2.0-20.0; SARA: M 3.51, SD 1.54, range 1.0-8.0). VP adults also showed significantly higher total ICARS (M 1.0, SD 1.99, range 0.0-11.0; p < .001) and SARA scores (M 0.54, SD 1.08, range 0.0-6.0; p < .001) than controls (ICARS: M 0.11, SD 0.44, range 0.0-2.0; SARA: M 0.04, SD 0.18, range 0.0-1.0). In conclusion, VP children showed significantly higher scores in ARS than controls. These differences were also present in VP adults, suggesting that deficits likely prevail until adulthood. ARS are a time and cost-effective method to screen for difficulties in coordination and balance in a patient group at risk.

Real-life Wrist Movement Patterns Capture Motor Impairment in Individuals with Ataxia-Telangiectasia

Sensitive motor outcome measures are needed to efficiently evaluate novel therapies for neurodegenerative diseases. Devices that can passively collect movement data in the home setting can provide continuous and ecologically valid measures of motor function. We tested the hypothesis that movement patterns extracted from continuous wrist accelerometer data capture motor impairment and disease progression in ataxia-telangiectasia. One week of continuous wrist accelerometer data were collected from 31 individuals with ataxia-telangiectasia and 27 controls aged 2-20 years old. Longitudinal wrist sensor data were collected in 14 ataxia-telangiectasia participants and 13 controls. A novel algorithm was developed to extract wrist submovements from the velocity time series. Wrist sensor features were compared with caregiver-reported motor function on the Caregiver Priorities and Child Health Index of Life with Disabilities survey and ataxia severity on the neurologist-performed Brief Ataxia Rating Scale. Submovements became smaller, slower, and less variable in ataxia-telangiectasia compared to controls. High-frequency oscillations in submovements were increased, and more variable and low-frequency oscillations were decreased and less variable in ataxia-telangiectasia. Wrist movement features correlated strongly with ataxia severity and caregiver-reported function, demonstrated high reliability, and showed significant progression over a 1-year interval. These results show that passive wrist sensor data produces interpretable and reliable measures that are sensitive to disease change, supporting their potential as ecologically valid motor biomarkers. The ability to obtain these measures from a low-cost sensor that is ubiquitous in smartwatches could help facilitate neurological care and participation in research regardless of geography and socioeconomic status.

Development of Cerebellar Reserve

The cerebellar reserve is defined as the capacity of the cerebellum for compensation and restoration following injury. This unique cerebellar ability is attributed to various forms of synaptic plasticity that incorporate multimodal and redundant cerebellar inputs, two major features of the cerebellar circuitry. It is assumed that the cerebellar reserve is acquired from the age of 12 years after the maturation of both the cerebellar adaptative behaviors and cerebellar functional connectivity. However, acquiring the cerebellar reserve is also affected by two other factors: vulnerability and growth potential in the developing cerebellum. First, cerebellar injury during the critical period of neural circuit formation (especially during fetal and neonatal life and infancy) leads to persistent dysfunction of the cerebellum and its targets, resulting in the limitation of the cerebellar reserve. Secondly, growth potential appears to facilitate cerebellar reserve during the stage when the cerebellar reserve is still immature. Based on these findings, the present mini-review proposes a possible developmental trajectory underlying the acquisition of cerebellar reserve. We highlight the importance of studies dedicated to the understanding of the cerebellar resilience to injuries.

Application of the Scale for Assessment and Rating of Ataxia in toddlers

INTRODUCTION

In young children with early onset ataxia (EOA), quantitative rating of ataxia by the Scale for Assessment and Rating of Ataxia (SARA) is longitudinally influenced by the physiological age effect on motor coordination. To enable longitudinal quantitative interpretation of ataxia by SARA in children with EOA, the EPNS ataxia working group has previously determined SARA-scores in typically developing children (4-16 years of age). In toddlers, this information is still lacking. We therefore aimed to investigate the feasibility and reliability of SARA-scores in typically developing toddlers.

METHODS

In 57 typically developing toddlers (2-4 years), we aimed to determine the: 1. feasibility of SARA-scores, 2. age-related pre-requisites to obtain SARA-scores in toddlers over all domains, 3. SARA-score reliability, 4. mathematical age connection of SARA-scores in toddlers and older children.

RESULTS

In typically developing toddlers, the feasibility of SARA is strongly age-dependent (p < .000). After computing compensations for two age-related, unfeasible and therefore un-assessable kinetic subtasks and after allowing the videotaping of non-kinetic SARA sub-task performances at home, the SARA was fully reliably assessable in all (n = 57) toddlers (ICC = 0.732). From two to 16 years of age, SARA-scores were mathematically represented by one continuous, exponentially decreasing trend line approaching the adult-optimum at 16 years of age.

CONCLUSION

In toddlers, SARA-scores are reliably assessable, by using two age-compensations and allowing the videotaping of SARA-performances partly at home. In children with EOA, these data enable longitudinal quantification and interpretation of quantitative ataxia-scores by SARA from 2 years of age throughout childhood.

Epidemiology of pediatric essential tremor in the United States: a systematic literature review from 2010 to 2020

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Applicability of quantitative oculomotor and SARA assessment in children

BACKGROUND

In clinical practice, eye movements can provide an early diagnostic marker for early onset ataxia (EOA). However, quantitative oculomotor assessment is not included in the most frequently used and age-validated ataxia rating scale in children, the Scale for the Assessment and Rating of Ataxia (SARA). We aimed to investigate the applicability of semi-quantitative eye movement assessment by the International Cooperative Ataxia Rating Scale (ICARS_OCM) and Ocular Motion Score (OMS_7-10) complementary to SARA measurements in children.

METHODS

In 52 typically developing children (aged 4-16 years; n = 4 per year of age), three independent assessors scored saccadic eye movements and ocular pursuit according to the ICARS_OCM and matching parameters from the OMS_7-10. For ICARS_OCM, we determined 1) construct validity for coordinated eye movements by correlation with OMS_7-10, ICARS_{EYE-HAND-COORDINATION} and SARA subscale scores, 2) agreement percentage and inter-rater agreement (Fleiss Kappa) and 3) age-dependency.

RESULTS

Spearman's rank correlations of ICARS_OCM with OMS_7-10 and ICARS- and SARA subscales were moderate to fair (all p < .001). Inter-rater agreement of ICARS-_OCM was 80.8%; (Fleiss Kappa: 0.411). ICARS_OCM scores revealed a similar exponentially decreasing association with age as the other SARA (sub)scores, reaching a plateau at 10 years of age.

INTERPRETATION

ICARS_OCM has a valid construct for the measurement of coordinated eye movement performance and is reliably assessable in children. ICARS_OCM reveals a similar age-dependent relationship as the other ataxia subscales, reflecting the physiological maturation of the cerebellum. In children, these data may implicate that ICARS_OCM can reliably contribute to coordination assessment, complementary to the SARA subscales.

Genetic and Clinical Predictors of Ataxia in Pediatric Primary Mitochondrial Disorders

Evaluation of ataxia in children is challenging in clinical practice. This is particularly true for highly heterogeneous conditions such as primary mitochondrial disorders (PMD). This study aims to explore cerebellar and brain abnormalities identified on MRI as potential predictors of ataxia in patients with PMD and, likewise, to determine the effect of the patient's genetic profile on these predictors as well as determination of the temporal relationship of clinical ataxia with MRI findings. We evaluated clinical, radiological, and genetic characteristics of 111 PMD patients younger than 21 years of age at The Children's Hospital of Philadelphia. Data was extracted from charts. Blinded radiological evaluations were carried out by experienced neuroradiologists. Multivariate logistic regression and generalized equation estimates were used for analysis. Ataxia was identified in 41% of patients. Cerebellar atrophy or putaminal involvement with mitochondrial DNA (mtDNA) mutations (OR 1.18, 95% CI 1.1-1.3, p < 0.001) and nuclear DNA mutation with no atrophy of the cerebellum (OR 1.14, 95% CI 1.0-1.3, p = 0.007) predicted an increased likelihood of having ataxia per year of age. Central tegmental tract predicted the presence of ataxia independent of age and pathogenic variant origin (OR 9.8, 95% CI 2-74, p = 0.009). Ataxia tended to precede the imaging finding of cerebellar atrophy. Cerebellar atrophy and putaminal involvement on MRI of pediatric-onset PMD may predict the presence of ataxia with age in patients with mtDNA mutations. This study provides predicted probabilities of having ataxia per year of age that may help in family counseling and future research of the population.

Clinical and radiological correlates of activities of daily living in cerebellar atrophy caused by PMM2 mutations (PMM2-CDG)

We aimed to identify clinical, molecular and radiological correlates of activities of daily living (ADL) in patients with cerebellar atrophy caused by PMM2 mutations (PMM2-CDG), the most frequent congenital disorder of glycosylation. Twenty-six PMM2-CDG patients (12 males; mean age 13 ± 11.1 years) underwent a standardized assessment to measure ADL, ataxia (brief ataxia rating scale, BARS) and phenotype severity (Nijmegen CDG rating scale, NCRS). MRI biometry of the cerebellum and the brainstem were performed in 23 patients (11 males; aged 5 months-18 years) and 19 control subjects with equal gender and age distributions. The average total ADL score was 15.3 ± 8.5 (range 3-32 out of 36 indicating severe functional disability), representing variable functional outcome in PMM2-CDG patients. Total ADL scores were significantly correlated with NCRS (r² = 0.55, p < 0.001) and BARS scores (r² = 0.764; p < 0.001). Severe intellectual disability, peripheral neuropathy, and severe PMM2 variants were all significantly associated with worse functional outcome. Higher ADL scores were significantly associated with decreased diameters of cerebellar vermis (r² = 0.347; p = 0.004), hemispheres (r² = 0.436; p = 0.005), and brainstem, particularly the mid-pons (r² = 0.64; p < 0.001) representing the major radiological predictor of functional disability score in multivariate regression analysis. We show that cerebellar syndrome severity, cognitive level, peripheral neuropathy, and genotype correlate with ADL used to quantify disease-related deficits in PMM2-CDG. Brainstem involvement should be regarded among functional outcome predictors in patients with cerebellar atrophy caused by PMM2-CDG.

Ataxia and mobility in children following surgical resection of posterior fossa tumour: A longitudinal cohort study

PURPOSE

To report the course of ataxia in children up to 2 years post-operatively, following surgical resection of a posterior fossa tumour (PFT).

METHODS

Thirty-five children, (median age 9 years, range 4-15) having resection of PFT, were assessed using the Scale for the Assessment and Rating of Ataxia (SARA), Brief Ataxia Rating Scale (BARS) and the mobility domain of the Paediatric Evaluation of Disability Index (PEDI-m) at initial post-operative period (baseline), 3 months, 1 year and 2 years post-operatively.

RESULTS

Baseline median scores of the SARA and BARS were 8.5 (range 0-35.5), and 7 (0-25) respectively. Ataxia improved at 3 months (median SARA and BARS reduction 3.5 and 4, respectively). Additional gradual improvements in SARA were recorded at 1 (median reduction 2) and 2 years post-operatively (median reduction 0.5). Median baseline PEDI-m was 54.75 (range 15.2-100) with improvement at 3 months (median increase 36.95) and small improvement at 1 year (median increase 2.5) and 2 years (median increase 5.8). Children with medulloblastoma and midline tumours (median baseline SARA 10 and 11, respectively) demonstrated more severe ataxia than children with low-grade gliomas and unilateral tumours (median baseline SARA 7.5 and 6.5, respectively).

CONCLUSION

The largest improvement in ataxia scores and functional mobility scores is demonstrated within the first 3 months post-operatively, but ongoing gradual improvement is observed at 2 years. Children with medulloblastoma and midline tumour demonstrated higher ataxia scores long term.

Mapping of long-term cognitive and motor deficits in pediatric cerebellar brain tumor survivors into a cerebellar white matter atlas

PURPOSE

Diaschisis of cerebrocerebellar loops contributes to cognitive and motor deficits in pediatric cerebellar brain tumor survivors. We used a cerebellar white matter atlas and hypothesized that lesion symptom mapping may reveal the critical lesions of cerebellar tracts.

METHODS

We examined 31 long-term survivors of pediatric posterior fossa tumors (13 pilocytic astrocytoma, 18 medulloblastoma). Patients underwent neuronal imaging, examination for ataxia, fine motor and cognitive function, planning abilities, and executive function. Individual consolidated cerebellar lesions were drawn manually onto patients' individual MRI and normalized into Montreal Neurologic Institute (MNI) space for further analysis with voxel-based lesion symptom mapping.

RESULTS

Lesion symptom mapping linked deficits of motor function to the superior cerebellar peduncle (SCP), deep cerebellar nuclei (interposed nucleus (IN), fastigial nucleus (FN), ventromedial dentate nucleus (DN)), and inferior vermis (VIIIa, VIIIb, IX, X). Statistical maps of deficits of intelligence and executive function mapped with minor variations to the same cerebellar structures.

CONCLUSION

We identified lesions to the SCP next to deep cerebellar nuclei as critical for limiting both motor and cognitive function in pediatric cerebellar tumor survivors. Future strategies safeguarding motor and cognitive function will have to identify patients preoperatively at risk for damage to these critical structures and adapt multimodal therapeutic options accordingly.

Early Onset Ataxia with Comorbid Dystonia: Clinical, Anatomical and Biological Pathway Analysis Expose Shared Pathophysiology

In degenerative adult onset ataxia (AOA), dystonic comorbidity is attributed to one disease continuum. However, in early adult onset ataxia (EOA), the prevalence and pathogenesis of dystonic comorbidity (EOAD⁺), are still unclear. In 80 EOA-patients, we determined the EOAD⁺-prevalence in association with MRI-abnormalities. Subsequently, we explored underlying biological pathways by genetic network and functional enrichment analysis. We checked pathway-outcomes in specific EOAD⁺-genotypes by comparing results with non-specifically (in-silico-determined) shared genes in up-to-date EOA, AOA and dystonia gene panels (that could concurrently cause ataxia and dystonia). In the majority (65%) of EOA-patients, mild EOAD⁺-features concurred with extra-cerebellar MRI abnormalities (at pons and/or basal-ganglia and/or thalamus (p = 0.001)). Genetic network and functional enrichment analysis in EOAD⁺-genotypes indicated an association with organelle- and cellular-component organization (important for energy production and signal transduction). In non-specifically, in-silico-determined shared EOA, AOA and dystonia genes, pathways were enriched for Krebs-cycle and fatty acid/lipid-metabolic processes. In frequently occurring EOAD⁺-phenotypes, clinical, anatomical and biological pathway analyses reveal shared pathophysiology between ataxia and dystonia, associated with cellular energy metabolism and network signal transduction. Insight in the underlying pathophysiology of heterogeneous EOAD⁺-phenotype-genotype relationships supports the rationale for testing with complete, up-to-date movement disorder gene lists, instead of single EOA gene-panels.

Validation of low-cost system for gait assessment in children with ataxia

BACKGROUND

Ataxic syndromes include several rare, inherited and acquired conditions. One of the main issues is the absence of specific, and sensitive automatic evaluation tools and digital outcome measures to obtain a continuous monitoring of subjects' motor ability.

OBJECTIVES

This study aims to test the usability of the Kinect system for assessing ataxia severity, exploring the potentiality of clustering algorithms and validating this system with a standard motion capture system.

METHODS

Gait evaluation was performed by standardized gait analysis and by Kinect v2 during the same day in a cohort of young patient (mean age of 13.8±7.2). We analyzed the gait spatio-temporal parameters and we looked at the differences between the two systems through correlation and agreement tests. As well, we tested for possible correlations with the SARA scale as well. Finally, standard classification algorithm and principal components analysis were used to discern disease severity and groups.

RESULTS

We found biases and linear relationships between all the parameters. Significant correlations emerged between the SARA and the Speed, the Stride Length and the Step Length. PCA results, highlighting that a machine learning approach combined with Kinect-based evaluation shows great potential to automatically assess disease severity and diagnosis.

CONCLUSIONS

The spatio-temporal parameters measured by Kinect cannot be used interchangeably with those parameters acquired with standard motion capture system in clinical practice but can still provide fundamental information. Specifically, these results might bring to the development of a novel system to perform easy and quick evaluation of gait in young patients with ataxia, useful for patients stratification in terms of clinical severity and diagnosis.

Assessment of Ataxia Rating Scales and Cerebellar Functional Tests: Critique and Recommendations

BACKGROUND

We assessed the clinimetric properties of ataxia rating scales and functional tests, and made recommendations regarding their use.

METHODS

A systematic literature search was conducted to identify the instruments used to rate ataxia symptoms. The identified rating scales and functional ability tests were reviewed and ranked by the panel as "recommended," "suggested," or "listed" for the assessment of patients with discrete cerebellar disorders, using previously established criteria.

RESULTS

We reviewed 14 instruments (9 rating scales and 5 functional tests). "Recommended" rating scales for the assessment of symptoms severity were: for Friedreich's ataxia, the Friedreich's Ataxia Rating Scale, the International Cooperative Ataxia Rating Scale (ICARS), and the Scale for the Assessment and Rating of Ataxia (SARA); for spinocerebellar ataxias, ICARS and SARA; for ataxia telangiectasia: ICARS and SARA; for brain tumors, SARA; for congenital disorder of glycosylation-phosphomannomutase-2 deficiency, ICARS; for cerebellar symptoms in multiple sclerosis, ICARS; for cerebellar symptoms in multiple system atrophy: Unified Multiple System Atrophy Rating Scale and ICARS; and for fragile X-associated tremor ataxia syndrome, ICARS. "Recommended" functional tests were: for Friedreich's ataxia, Ataxia Functional Composite Score and Composite Cerebellar Functional Severity Score; and for spinocerebellar ataxias, Ataxia Functional Composite Score, Composite Cerebellar Functional Severity Score, and SCA Functional Index.

CONCLUSIONS

We identified some "recommended" scales and functional tests for the assessment of patients with major hereditary ataxias and other cerebellar disorders. The main limitations of these instruments include the limited assessment of patients in the more severe end of the spectrum and children. Further research in these populations is warranted. © 2020 International Parkinson and Movement Disorder Society.

Development of a clinical scale for assessment of patients with diffuse intrinsic pontine glioma (DIPG) receiving experimental therapy: the PONScore

PURPOSE

Monitoring neurological side-effects in experimental therapy for diffuse intrinsic pontine glioma (DIPG) can be challenging. We aimed to develop a neurological scale that could be used by non-specialists to quantify neurological changes during experimental treatment of DIPG.

METHODS

We developed the Pontine Observational Neurological Score (PONScore) to measure signs and symptoms of DIPG by adapting validated assessment scales of neurological signs and symptoms in children. We developed a prototype score, taught it to paediatric intensive care nursing staff, who used the Score to assess children receiving awake pontine infusion of chemotherapy for treatment of DIPG. We used their feedback to develop the PONScore. Points are allocated for headache, ophthalmoplegia, facial and tongue weakness, dysarthria, paraesthesia, limb weakness and dysmetria with increasing scores reflecting increasing disability. The PONScore was administered every hour during awake pontine infusion. Correlation and agreement calculations between nursing staff, as non-specialists, and a specialist rater were performed in 30 infusions in 6 children (aged 8-11). Changes in PONScore versus volume of infusion are described in a further 55 infusions in 8 children (aged 3-11).

RESULTS

The PONScore demonstrated excellent intra-rater reliability with an intra-class co-efficient of 0.98 (95% CI 0.97-0.99; p-value < 0.001) between a specialist and non-specialist raters with strong correlation between scores and a Spearman correlation coefficient of 0.985 (p < 0.001). PONScores increased from 3.3 to 5.7 (p-value < 0.001) during infusion reflecting accumulation of neurological signs and symptoms during infusion.

CONCLUSIONS

We describe a novel neurological scale that can be used by non-specialists to describe acute neurological changes in children receiving experimental therapy for DIPG. Prospective validation as part of a clinical trial is required.

Paediatric motor phenotypes in early-onset ataxia, developmental coordination disorder, and central hypotonia

AIMS

To investigate the accuracy of phenotypic early-onset ataxia (EOA) recognition among developmental conditions, including developmental coordination disorder (DCD) and hypotonia of central nervous system origin, and the effect of scientifically validated EOA features on changing phenotypic consensus.

METHOD

We included 32 children (4-17y) diagnosed with EOA (n=11), DCD (n=10), and central hypotonia (n=11). Three paediatric neurologists independently assessed videotaped motor behaviour phenotypically and quantitatively (using the Scale for Assessment and Rating of Ataxia [SARA]). We determined: (1) phenotypic interobserver agreement and phenotypic homogeneity (percentage of phenotypes with full consensus by all three observers according to the underlying diagnosis); (2) SARA (sub)score profiles; and (3) the effect of three scientifically validated EOA features on phenotypic consensus.

RESULTS

Phenotypic homogeneity occurred in 8 out of 11, 2 out of 10, and 1 out of 11 patients with EOA, DCD, and central hypotonia respectively. Homogeneous phenotypic discrimination of EOA from DCD and central hypotonia occurred in 16 out of 21 and 22 out of 22 patients respectively. Inhomogeneously discriminated EOA and DCD phenotypes (5 out of 21) revealed overlapping SARA scores with different SARA subscore profiles. After phenotypic reassessment with scientifically validated EOA features, phenotypic homogeneity changed from 16 to 18 patients.

INTERPRETATION

In contrast to complete distinction between EOA and central hypotonia, the paediatric motor phenotype did not reliably distinguish between EOA and DCD. Reassessment with scientifically validated EOA features could contribute to a higher phenotypic consensus. Early-onset ataxia (EOA) and central hypotonia motor phenotypes were reliably distinguished. EOA and developmental coordination disorder (DCD) motor phenotypes were not reliably distinguished. The EOA and DCD phenotypes have different profiles of the Scale for Assessment and Rating of Ataxia.

Turkish version of Brief Ataxia Rating Scale

AIM

Our aim was to perform the Turkish-language adaptation of a practical ataxia rating scale for children.

METHODS

The Brief Ataxia Rating Scale was subjected to cultural adaptation following receipt of the requisite permissions. Thirty-six children aged 4-18 years followed-up with a diagnosis of ataxia were included in the study. Evaluation of each child was recorded on video. The video recordings were scored independently by nine observers (four physiotherapists, one pediatric neurologist, and four pediatricians). Intra-rater reliability was tested by the same video images being scored twice, at 15-day intervals, by a pediatric neurologist. Intraclass correlation coefficients were used for inter-rater and intra-rater reliability. The Scale for the Assessment and Rating of Ataxia was used for concurrent validity.

RESULTS

Good to excellent reliability was determined among the nine observers in terms of total scores with the intraclass correlation coefficient among the nine observers (intraclass correlation coefficient = 0.926; 95% CI: 0.885-0.956). Intra-rater reliability analysis results exhibited strong reliability in terms of scores elicited at two-week intervals (intraclass correlation coefficient = 0.967; 95% CI: 0.890-0.987, r = 0.97, p < 0.001). At concurrent validity analysis, a strong relation was determined between total Scale of the Assessment and Rating of Ataxia score and total Brief Ataxia Rating Scale score (r = 0.942, p < 0.001).

CONCLUSION

The Turkish-language adaptation of the Brief Ataxia Rating Scale is reliable and valid for application in children.Implications for RehabilitationThis study shows the reliability and validity of the Turkish language adaptation of brief ataxia rating scale in children.The scale being both practical and easily applicable to ataxic children will contribute to broadening its use in the pediatric age group in particular.

A clinical diagnostic algorithm for early onset cerebellar ataxia

Early onset cerebellar Ataxia (EOAc) comprises a large group of rare heterogeneous disorders. Determination of the underlying etiology can be difficult given the broad differential diagnosis and the complexity of the genotype-phenotype relationships. This may change the diagnostic work-up into a time-consuming, costly and not always rewarding task. In this overview, the Childhood Ataxia and Cerebellar Group of the European Pediatric Neurology Society (CACG-EPNS) presents a diagnostic algorithm for EOAc patients. In seven consecutive steps, the algorithm leads the clinician through the diagnostic process, including EOA identification, application of the Inventory of Non-Ataxic Signs (INAS), consideration of the family history, neuro-imaging, laboratory investigations, genetic testing by array CGH and Next Generation Sequencing (NGS). In children with EOAc, this algorithm is intended to contribute to the diagnostic process and to allow uniform data entry in EOAc databases.

Motor function in survivors of pediatric acute lymphoblastic leukemia treated with chemotherapy-only

BACKGROUND

Up to 43% of survivors of pediatric acute lymphoblastic leukemia (ALL) may exhibit fine-motor problems. Information on manual dexterity in this cohort is still limited.

OBJECTIVES

We tested survivors of childhood ALL treated with chemotherapy-only for fine-motor function in terms of drawing and handwriting abilities using a Digitizing Tablet (DT) with three tasks for drawing and handwriting of varying complexity, for ataxia using the International Cooperative Ataxia Rating Scale (ICARS), and for tremor and hand-eye coordination using the Nine Hole Steadiness Tester (NHST).

RESULTS

We examined a cohort of non-irradiated survivors (n = 31) after a median time of 3.5 years after end of therapy. In all tasks of the DT the cohort demonstrated significant (p < 0.05) impairment of speed, automation, and variability in at least two tasks and significantly more pressure. Impaired speed (SPV) inversely correlated with lag time since end of therapy. Dexterity performance of six survivors (19%) lay below the 5th percentile. No survivor exhibited ataxia, tremor, or impaired hand-steadiness.

CONCLUSION

Despite the absence of gross ataxia, tremor, and impaired hand-eye coordination, we nevertheless detected significant fine-motor impairment in a relevant number of survivors of childhood ALL. Prospective studies are needed to reveal the pathophysiological underpinnings and genetic risk factors for development of such deficits due to ALL and its treatment.

The neurological phenotype of developmental motor patterns during early childhood

INTRODUCTION

During early childhood, typical human motor behavior reveals a gradual transition from automatic motor patterns to acquired motor skills, by the continuous interplay between nature and nurture. During the wiring and shaping of the underlying motor networks, insight into the neurological phenotype of developmental motor patterns is incomplete. In healthy, typically developing children (0-3 years of age), we therefore aimed to investigate the neurological phenotype of developmental motor patterns.

METHODS

In 32 healthy, typically developing children (0-3 years), we video-recorded spontaneous motor behavior, general movements (GMs), and standardized motor tasks. We classified the motor patterns by: (a) the traditional neurodevelopmental approach, by Gestalt perception and (b) the classical neurological approach, by the clinical phenotypic determination of movement disorder features. We associated outcomes by Cramer's V.

RESULTS

Developmental motor patterns revealed (a) choreatic-like features (≤3 months; associated with fidgety GMs (r = 0.732) and startles (r = 0.687)), (b) myoclonic-like features (≤3 months; associated with fidgety GMs (r = 0.878) and startles (r = 0.808)), (c) dystonic-like features (0-3 years; associated with asymmetrical tonic neck reflex (r = 0.641) and voluntary movements (r = 0.517)), and (d) ataxic-like features (>3 months; associated with voluntary movements (r = 0.928)).

CONCLUSIONS

In healthy infants and toddlers (0-3 years), typical developmental motor patterns reveal choreatic-, myoclonic-, dystonic- and ataxic-like features. The transient character of these neurological phenotypes is placed in perspective of the physiological shaping of the underlying motor centers. Neurological phenotypic insight into developmental motor patterns can contribute to adequate discrimination between ontogenetic and initiating pathological movement features and to adequate interpretation of therapeutic interactions.

Instrumented finger-to-nose test classification in children with ataxia or developmental coordination disorder and controls

BACKGROUND

During childhood, many conditions may impact coordination. Examples are physiological age-related development and pathological conditions, such as early onset ataxia and developmental coordination disorder. These conditions are generally diagnosed by clinical specialists. However, in absence of a gold phenotypic standard, objective reproducibility among specialists appears limited.

METHODS

We investigated whether quantitative analysis of an upper limb coordination task (the finger-to-nose test) could discriminate between physiological and pathological conditions impacting coordination. We used inertial measurement units to estimate movement trajectories of the participants while they executed the finger-to-nose test. We employed random forests to classify each participant in one category.

FINDINGS

On average, 87.4% of controls, 74.4% of early onset ataxia and 24.8% of developmental coordination disorder patients were correctly classified. The relatively good classification of early onset ataxia patients and controls contrasts with the poor classification of developmental coordination disorder patients.

INTERPRETATION

In absence of a gold phenotypic standard for developmental coordination disorder recognition, it remains elusive whether the finger-to-nose test in these patients represents a sufficiently accurate entity to reflect symptoms distinctive of this disorder. Based on the relatively good results in early onset ataxia patients and controls, we conclude that quantitative analysis of the finger-to-nose test can provide a reliable support tool during the assessment of phenotypic early onset ataxia.

The movement disorder spectrum of SCA21 (ATX-TMEM240): 3 novel families and systematic review of the literature

Spinocerebellar ataxia type 21 (SCA21/ATX-TMEM240) was recently found to be caused by mutations in TMEM240, with still limited knowledge on the phenotypic spectrum and disease course. Here we present five subjects from three novel SCA21 families from different parts of the world (including a novel c.196G > A, p.G66R TMEM240 variant from Colombia), demonstrating that, in addition to cerebellar ataxia, not only hypokinetic features (hypomimia, bradykinesia), but also hyperkinetic movement disorders (poly-mini-myoclonus, proximal myoclonus) are a recurrent part of the phenotypic spectrum of SCA21. Presenting first prospective longitudinal data, our results provide examples of two different disease trajectories: while it was inherently progressive in adult-onset cases, a dramatically improving trajectory was observed in an infantile-onset case. A systematic review of all previously reported SCA21 patients (n = 42) demonstrates that SCA21 is a relatively early-onset SCA (median onset age 18 years; range 1-61 years) with frequent non-cerebellar involvement, including hyporeflexia (69%), bradykinesia (65%), slow saccades (38%) and pyramidal signs (17%). Our results characterize SCA21 as a multisystem disorder with substantial extra-cerebellar involvement, including a wide spectrum of hypo- as well as hyperkinetic movement disorders as well as damage to the midbrain, corticospinal tract and peripheral nerves. However, in contrast to the current perspective on SCA21 disease, cognitive impairment is not an obligatory feature of the disease. The disease course is inherently progressive in adult-onset subjects, but might also be characterized by improvement in infantile-onset cases. These findings have important consequences of the work-up and counseling of SCA21/ATX-TMEM240 patients.

Incidence and prognostic factors of ataxia in children with posterior fossa tumors

Background

There is minimal literature specific to motor outcomes in children with posterior fossa tumors (PFTs) despite ataxia being a significant problem in this group. This study aims to report children's physical outcomes following management of PFT and determine which factors affect severity of ataxia and functional limitations.

Methods

Forty-two children aged between 5 and 17 and between 1 and 4 years following surgery for PFT were assessed using the Scale for the Assessment and Rating of Ataxia (SARA), the Brief Ataxia Rating Scale (BARS), and the mobility Pediatric Evaluation of Disability Inventory (PEDI) subscale to determine prevalence and severity of ataxia and a measure of physical function. Analysis was undertaken comparing impact of tumor location, tumor histology, adjuvant treatment, age at diagnosis, presence of preoperative ataxia, and presence of cerebellar mutism syndrome (CMS) on ataxia and physical function scores.

Results

Seventy-one percent of children demonstrated a SARA and BARS score greater than 2. A total of 48% of children had a PEDI-m score greater than 90. There was no correlation between age at diagnosis or preoperative ataxia and assessment scores. There was a significant difference in SARA/BARS and PEDI-mobility scores depending on tumor histology, tumor location, and presence of CMS.

Conclusions

A high proportion of children (>1 year) following surgery for PFT continue to present with ataxia. Higher ataxia and lower physical function scores were demonstrated in children with medulloblastoma and midline tumors and those diagnosed with CMS. The high prevalence of ataxia demonstrates the need for further research regarding rehabilitation management in this population.

Current behavioral assessments of movement disorders in children

Pediatric movement disorders (PMDs) are common and have recently received increasing attention. As these disorders have special clinical features, the selection of appropriate behavioral assessment tools that can clearly distinguish movement disorders from other diseases (eg, epilepsy and neuromuscular disorders) is crucial for achieving an accurate diagnosis and treatment. However, few studies have focused on behavioral assessments in children. The present report attempts to provide a critical review of the available subjective and objective assessment tests for common PMDs. We believe that the principles of objectification, multi-purpose use, and simplification are also applicable to the selection and development of satisfactory pediatric behavioral assessment tools. We expect that the development of wearable sensors, virtual reality, and augmented reality will lead to the establishment of more reliable and simple tests. In addition, more rigorous randomized controlled trials that have been specifically designed to evaluate behavioral testing in children are also expected in the future.

Physiological movement disorder-like features during typical motor development

AIM

To compare physiological age-relatedness between dyskinesia (dystonia/choreoathetosis), dystonia and ataxia rating scale scores in healthy children.

METHOD

Three movement disorders specialists quantified dyskinetic-like features in healthy children (n = 52; 4-16 years) using the Dyskinesia Impairment Scale (DIS = DIS-choreoathetosis (DIS-C) + DIS-dystonia (DIS-D)). We compared the age-related regression coefficients of the DIS with data processed from previous studies on dystonia and ataxia rating scales (Burke-Fahn-Marsden Movement and Disability Scales (BFMMS and BFMDS) and Scale for Assessment and Rating of Ataxia (SARA), International Cooperative Ataxia Rating Scale (ICARS) and Brief Ataxia Rating Scale (BARS)).

RESULTS

Dyskinetic scores were obtained in 79% (DIS); 65% (DIS-D) and 17% (DIS-C) versus dystonic and ataxic scores in 98% (BFMMS) and 89% (SARA/ICARS/BARS) of the children. Age-related DIS and DIS-D scores (B = -0.90 and 0.77; p < 0.001) were correlated with age-related BFMMS scores (B = -0.49; p < 0.001; r = 0.87; p < 0.001), whereas DIS-C scores were age-independent. Ataxic scores revealed stronger age-related regression coefficients than dyskinetic and dystonic scores (4-8 years; p < 0.05).

INTERPRETATION

In healthy children, comparison between physiological dyskinesia, dystonia and ataxia rating scale scores revealed: 1. inverse age-relatedness for dystonic and ataxic scores, but not for choreoathetotic scores, 2. interrelated dystonic DIS-D and BFMMS scores, 3. the strongest age-related expression by ataxic scores. In healthy children, these physiological movement disorder-like features are interpreted as an expression of the developing underlying motor centres.

Crossing barriers: a multidisciplinary approach to children and adults with young-onset movement disorders

Background

Diagnosis of less common young-onset movement disorders is often challenging, requiring a broad spectrum of skills of clinicians regarding phenotyping, normal and abnormal development and the wide range of possible acquired and genetic etiologies. This complexity often leads to considerable diagnostic delays, paralleled by uncertainty for patients and their families. Therefore, we hypothesized that these patients might benefit from a multidisciplinary approach. We report on the first 100 young-onset movement disorders patients who visited our multidisciplinary outpatient clinic.

Methods

Clinical data were obtained from the medical records of patients with disease-onset before age 18 years. We investigated whether the multidisciplinary team, consisting of a movement disorder specialist, pediatric neurologist, pediatrician for inborn errors of metabolism and clinical geneticist, revised the movement disorder classification, etiological diagnosis, and/or treatment.

Results

The 100 referred patients (56 males) had a mean age of 12.5 ± 6.3 years and mean disease duration of 9.2 ± 6.3 years. Movement disorder classification was revised in 58/100 patients. Particularly dystonia and myoclonus were recognized frequently and supported by neurophysiological testing in 24/29 patients. Etiological diagnoses were made in 24/71 (34%) formerly undiagnosed patients, predominantly in the genetic domain. Treatment strategy was adjusted in 60 patients, of whom 43 (72%) reported a subjective positive effect.

Conclusions

This exploratory study demonstrates that a dedicated tertiary multidisciplinary approach to complex young-onset movement disorders may facilitate phenotyping and improve recognition of rare disorders, with a high diagnostic yield and minimal diagnostic delay. Future studies are needed to investigate the cost-benefit ratio of a multidisciplinary approach in comparison to regular subspecialty care.

Scales for the clinical evaluation of cerebellar disorders

Clinical scales represent an important tool not only for the initial grading/scoring of disease and assessment of progression, but also for the quantification of therapeutic effects in clinical trials. There are several scales available for the clinical evaluation of cerebellar symptoms. While some scales have been developed and evaluated for specific cerebellar disorders such as Friedreich ataxia, others reliably capture cerebellar symptoms with no respect to the underlying etiology. Each scale has its strengths and weaknesses. Extensive scales are certainly useful for thorough documentation of specific features of certain phenotypes, but this gain of information is not always essential for the purpose of a study. Therefore, compact and manageable scales like the Scale for the Assessment and Rating of Ataxia (SARA) or Brief Ataxia Rating Scale (BARS) are often preferred compared to more complex scales in observational and therapeutic studies.

Cerebellar motor syndrome from children to the elderly

More than a century after the description of its cardinal components, the cerebellar motor syndrome (CMS) remains a cornerstone of daily clinical ataxiology, in both children and adults. Anatomically, motor cerebellum involves lobules I-V, VI, and VIII. CMS is typically associated with errors in the metrics of voluntary movements and a lack of coordination. Symptoms and motor signs consist of speech deficits, impairments of limb movements, and abnormalities of posture/gait. Ataxic dysarthria has a typical scanning (explosive with staccato) feature, voice has a nasal character, and speech is slurred. Cerebellar mutism is most common in children and occurs after resection of a large midline cerebellar tumor. Ataxia of limbs includes at various degrees dysmetria (hypermetria: overshoot, hypometria: undershoot), dysdiadochokinesia, cerebellar tremor (action tremor, postural tremor, kinetic tremor, some forms of orthostatic tremor), isometrataxia, disorders of muscle tone (both hypotonia and cerebellar fits), and impaired check and rebound. Handwriting is irregular and some patients exhibit megalographia. Cerebellar patients show an increased body sway with a broad-based stance (ataxia of stance). Gait is irregular and staggering. Delayed learning of complex motor skills may be a prominent feature in children. CMS is currently explained by the inability of the cerebellum to handle feedback signals during slow movements and to create, store, select, and update internal models during fast movements. The cerebellum is embedded in large-scale brain networks and is essential to perform accurate motor predictions related to body dynamics and environmental stimuli. Overall, the observations in children and adults exhibiting a CMS fit with the hypothesis that the cerebellum contains neural representations reproducing the dynamic properties of body, and generates and calibrates sensorimotor predictions. Therapies aiming at a reinforcement or restoration of internal models should be implemented to cancel CMS in cerebellar ataxias. The developmental trajectory of the cerebellum, the immature motor behavior in children, and the networks implicated in CMS need to be taken into account.

Cerebellar-dependent associative learning is impaired in very preterm born children and young adults

Preterm birth incorporates an increased risk for cerebellar developmental disorders likely contributing to motor and cognitive abnormalities. Experimental evidence of cerebellar dysfunction in preterm subjects, however, is sparse. In this study, classical eyeblink conditioning was used as a marker of cerebellar dysfunction. Standard delay conditioning was investigated in 20 adults and 32 preschool children born very preterm. Focal lesions were excluded based on structural magnetic resonance imaging. For comparison, an equal number of matched term born healthy peers were tested. Subgroups of children (12 preterm, 12 controls) were retested. Preterm subjects acquired significantly less conditioned responses (CR) compared to controls with slower learning rates. A likely explanation for these findings is that preterm birth impedes function of the cerebellum even in the absence of focal cerebellar lesions. The present findings are consistent with the assumption that prematurity results in long-term detrimental effects on the integrity of the cerebellum. It cannot be excluded, however, that extra-cerebellar pathology contributed to the present findings.

Construct Validity and Reliability of the SARA Gait and Posture Sub-scale in Early Onset Ataxia

Aim: In children, gait and posture assessment provides a crucial marker for the early characterization, surveillance and treatment evaluation of early onset ataxia (EOA). For reliable data entry of studies targeting at gait and posture improvement, uniform quantitative biomarkers are necessary. Until now, the pediatric test construct of gait and posture scores of the Scale for Assessment and Rating of Ataxia sub-scale (SARA) is still unclear. In the present study, we aimed to validate the construct validity and reliability of the pediatric (SARA_GAIT/POSTURE) sub-scale. Methods: We included 28 EOA patients [15.5 (6-34) years; median (range)]. For inter-observer reliability, we determined the ICC on EOA SARA_GAIT/POSTURE sub-scores by three independent pediatric neurologists. For convergent validity, we associated SARA_GAIT/POSTURE sub-scores with: (1) Ataxic gait Severity Measurement by Klockgether (ASMK; dynamic balance), (2) Pediatric Balance Scale (PBS; static balance), (3) Gross Motor Function Classification Scale -extended and revised version (GMFCS-E&R), (4) SARA-kinetic scores (SARA_KINETIC; kinetic function of the upper and lower limbs), (5) Archimedes Spiral (AS; kinetic function of the upper limbs), and (6) total SARA scores (SARA_TOTAL; i.e., summed SARA_GAIT/POSTURE, SARA_KINETIC, and SARA_SPEECH sub-scores). For discriminant validity, we investigated whether EOA co-morbidity factors (myopathy and myoclonus) could influence SARA_GAIT/POSTURE sub-scores. Results: The inter-observer agreement (ICC) on EOA SARA_GAIT/POSTURE sub-scores was high (0.97). SARA_GAIT/POSTURE was strongly correlated with the other ataxia and functional scales [ASMK (r_s = -0.819; p < 0.001); PBS (r_s = -0.943; p < 0.001); GMFCS-E&R (r_s = -0.862; p < 0.001); SARA_KINETIC (r_s = 0.726; p < 0.001); AS (r_s = 0.609; p = 0.002); and SARA_TOTAL (r_s = 0.935; p < 0.001)]. Comorbid myopathy influenced SARA_GAIT/POSTURE scores by concurrent muscle weakness, whereas comorbid myoclonus predominantly influenced SARA_KINETIC scores. Conclusion: In young EOA patients, separate SARA_GAIT/POSTURE parameters reveal a good inter-observer agreement and convergent validity, implicating the reliability of the scale. In perspective of incomplete discriminant validity, it is advisable to interpret SARA_GAIT/POSTURE scores for comorbid muscle weakness.

Age-related reference values for the pediatric Scale for Assessment and Rating of Ataxia: a multicentre study

AIM

For reliable assessment of ataxia severity in children, the Childhood Ataxia and Cerebellar Group of the European Pediatric Neurology Society aimed to validate the Scale for Assessment and Rating of Ataxia (SARA) according to age.

METHOD

Twenty-two pediatric ataxia experts from 15 international institutions scored videotaped SARA performances in 156 typically developing children (4-16y: m/f=1; 12 children per year of age; including nine different nationalities). We determined age-dependency and reliability of pediatric SARA scores by a mixed model.

RESULTS

In typically developing children, age was the only variable that revealed a relationship with SARA scores (p<0.001). The youngest children revealed the highest scores and the highest variation in scores (<8y; p<0.001). After 11 years of age, pediatric scores approached adult outcomes. The interobserver agreement of total SARA scores was substantial with an intraclass correlation coefficient of 0.63 (95% confidence interval 0.56-0.69; p<0.001).

INTERPRETATION

In typically developing European children, both SARA scores and interobserver agreement are age-dependent. For reliable interpretation of pediatric SARA scores, consideration of the underlying test construct appears prudent. These data will hopefully contribute to a correct and uniform interpretation of longitudinal SARA scores from childhood to adulthood.

A quantitative assessment of the evolution of cerebellar syndrome in children with phosphomannomutase-deficiency (PMM2-CDG)

Background

We aim to delineate the progression of cerebellar syndrome in children with phosphomannomutase-deficiency (PMM2-CDG) using the International Cooperative Ataxia Rating Scale (ICARS). We sought correlation between cerebellar volumetry and clinical situation. We prospectively evaluated PMM2-CDG patients aged from 5 to 18 years through ICARS at two different time points set apart by at least 20 months. We reviewed available MRIs and performed volumetric analysis when it was possible.

Results

From the eligible 24, four patients were excluded due to severe mental disability (n = 2) and supratentorial lesions (n = 2). Two different ICARS evaluations separated by more than 20 months were available for 14 patients showing an improvement in the cerebellar syndrome: ICARS1: 35.71 versus ICARS2: 30.07 (p < 0.001). When we considered time, we saw an improvement of 2.64 points in the ICARS per year with an SD of 1.97 points (p < 0.001). The ICARS subscales results improved with time, reaching statistical significance in “Posture and gait” (p < 0.001), “Kinetic functions” (p = 0.04) and “Speech abnormalities” (p = 0.045). We found a negative correlation between the ICARS results and total cerebellar volume (r = −0.9, p = 0.037) in a group of five patients with available volumetric study, meaning that the higher the ICARS score, the more severe was the cerebellar atrophy.

Conclusions

Our study shows a stabilization or mild improvement in the cerebellar functions of paediatric PMM2-CDG patients despite cerebellar volume loss. ICARS is a valid scale to quantify the evolution of cerebellar syndrome in PMM2-CDG patients. The availability of ICARS and other reliable and sensitive follow-up tools may prove essential for the evaluation of potential therapies.

Electronic supplementary material

The online version of this article (10.1186/s13023-017-0707-0) contains supplementary material, which is available to authorized users.

Reliability and discriminant validity of ataxia rating scales in early onset ataxia

AIM

To determine whether ataxia rating scales are reliable disease biomarkers for early onset ataxia (EOA).

METHOD

In 40 patients clinically identified with EOA (28 males, 12 females; mean age 15y 3mo [range 5-34y]), we determined interobserver and intraobserver agreement (interclass correlation coefficient [ICC]) and discriminant validity of ataxia rating scales (International Cooperative Ataxia Rating Scale [ICARS], Scale for Assessment and Rating of Ataxia [SARA], and Brief Ataxia Rating Scale [BARS]). Three paediatric neurologists independently scored ICARS, SARA and BARS performances recorded on video, and also phenotyped the primary and secondary movement disorder features. When ataxia was the primary movement disorder feature, we assigned patients to the subgroup 'EOA with core ataxia' (n=26). When ataxia concurred with other prevailing movement disorders (such as dystonia, myoclonus, and chorea), we assigned patients to the subgroup 'EOA with comorbid ataxia' (n=12).

RESULTS

ICC values were similar in both EOA subgroups of 'core' and 'comorbid' ataxia (0.92-0.99; ICARS, SARA, and BARS). Independent of the phenotype, the severity of the prevailing movement disorder predicted the ataxia rating scale scores (β=0.83-0.88; p<0.05).

INTERPRETATION

In patients with EOA, the reliability of ataxia rating scales is high. However, the discriminative validity for 'ataxia' is low. For adequate interpretation of ataxia rating scale scores, application in uniform movement disorder phenotypes is essential.

Automatic classification of gait in children with early-onset ataxia or developmental coordination disorder and controls using inertial sensors

Early-Onset Ataxia (EOA) and Developmental Coordination Disorder (DCD) are two conditions that affect coordination in children. Phenotypic identification of impaired coordination plays an important role in their diagnosis. Gait is one of the tests included in rating scales that can be used to assess motor coordination. A practical problem is that the resemblance between EOA and DCD symptoms can hamper their diagnosis. In this study we employed inertial sensors and a supervised classifier to obtain an automatic classification of the condition of participants. Data from shank and waist mounted inertial measurement units were used to extract features during gait in children diagnosed with EOA or DCD and age-matched controls. We defined a set of features from the recorded signals and we obtained the optimal features for classification using a backward sequential approach. We correctly classified 80.0%, 85.7%, and 70.0% of the control, DCD and EOA children, respectively. Overall, the automatic classifier correctly classified 78.4% of the participants, which is slightly better than the phenotypic assessment of gait by two pediatric neurologists (73.0%). These results demonstrate that automatic classification employing signals from inertial sensors obtained during gait maybe used as a support tool in the differential diagnosis of EOA and DCD. Furthermore, future extension of the classifier's test domains may help to further improve the diagnostic accuracy of pediatric coordination impairment. In this sense, this study may provide a first step towards incorporating a clinically objective and viable biomarker for identification of EOA and DCD.

Functional and Gait Assessment in Children and Adolescents Affected by Friedreich's Ataxia: A One-Year Longitudinal Study

Friedreich's ataxia is the most common autosomal recessive form of neurodegenerative ataxia. We present a longitudinal study on the gait pattern of children and adolescents affected by Friedreich's ataxia using Gait Analysis and the Scale for the Assessment and Rating of Ataxia (SARA). We assessed the spectrum of changes over 12 months of the gait characteristics and the relationship between clinical and instrumental evaluations. We enrolled 11 genetically confirmed patients affected by Friedreich's ataxia in this study together with 13 normally developing age-matched subjects. Eight patients completed a 12-month follow-up under the same protocol. By comparing the gait parameters of Friedreich's ataxia with the control group, we found significant differences for some relevant indexes. In particular, the increased knee and ankle extension in stance revealed a peculiar biomechanical pattern, which correlated reliably with SARA Total, Gait and Sitting scores. The knee pattern showed its consistency also at the follow-up: Knee extension increased from 6.8±3.5° to -0.5±3.7° and was significantly correlated with the SARA total score. This feature anticipated the loss of the locomotor function in two patients. In conclusion, our findings demonstrate that the selective and segmental analysis of kinetic/kinematic features of ataxic gait, in particular the behavior of the knee, provides sensitive measures to detect specific longitudinal and functional alterations, more than the SARA scale, which however has proved to be a reliable and practical assessment tool. Functional outcomes measures integrated by instrumental evaluation increase their sensitivity, reliability and suitability for the follow-up of the disease progression and for the application in clinical trials and in rehabilitative programs.

The Burke-Fahn-Marsden Dystonia Rating Scale is Age-Dependent in Healthy Children

Background

The Burke-Fahn-Marsden Dystonia Rating Scale is a universally applied instrument for the quantitative assessment of dystonia in both children and adults. However, immature movements by healthy young children may also show "dystonic characteristics" as a consequence of physiologically incomplete brain maturation. This could implicate that Burke-Fahn-Marsden scale scores are confounded by pediatric age.

Objective

In healthy young children, we aimed to determine whether physiologically immature movements and postures can induce an age-related effect on Burke-Fahn-Marsden movement and disability scale scores.

Methods

Nine assessors specializied in movement disorders (3 adult neurologists, 3 pediatric neurologists, and 3 MD/PhD students) independently scored the Burke-Fahn-Marsden movement scale in 52 healthy children (4-16 years of age; 2 boys and 2 girls per year of age). Independent of that, parents scored their children's functional motor development according to the Burke-Fahn-Marsden disability scale in another 52 healthy children (4-16 years of age; 2 boys and 2 girls per year of age). By regression analysis, we determined the association between Burke-Fahn-Marsden movement and disability scales outcomes and pediatric age.

Results

In healthy children, assessment of physiologically immature motor performances by the Burke-Fahn-Marsden movement and disability scales showed an association between the outcomes of both scales and age (until 16 years and 12 years of age, β = -0.72 and β = -0.60, for Burke-Fahn-Marsden movement and disability scale, respectively [both P < 0.001]).

Conclusions

The Burke-Fahn-Marsden movement and disability scales are influenced by the age of the child. For accurate interpretation of longitudinal Burke-Fahn-Marsden Dystonia Rating Scale scores in young dystonic children, consideration of pediatric age-relatedness appears advisory.

Standardized Assessment of Hereditary Ataxia Patients in Clinical Studies

BACKGROUND

Hereditary ataxias are a heterogeneous group of degenerative diseases of the cerebellum, brainstem, and spinal cord. They may present with isolated ataxia or with additional symptoms going beyond cerebellar deficits. There are an increasing number of clinical studies with the goal to define the natural history of these disorders, develop biomarkers, and investigate therapeutic interventions. Especially, early and preclinical disease stages are currently of particular interest.

METHODS AND RESULTS

Evidence-based, we review standards for sampling and storage of biomaterials, clinical and neuropsychological assessment, as well as neurophysiology and neuroimaging and recommendations for standardized assessment of ataxia patients in multicenter studies.

CONCLUSIONS

DNA, RNA, serum, and, if possible, cerebrospinal fluid samples should be processed following established standards. Clinical assessment in ataxia studies must include use of a validated clinical ataxia scale. There are several validated clinical ataxia scales available. There are no instruments that were specifically designed for assessing neuropsychological and psychiatric symptoms in ataxia disorders. We provide a list of tests that may prove valuable. Quantitative performance tests have the potential to supplement clinical scales. They provide additional objective and quantitative information. Posturography and quantitative movement analysis-despite valid approaches-require standardization before implemented in multicenter studies. Standardization of neurophysiological tools, as required for multicenter interventional trials, is still lacking. Future multicenter neuroimaging studies in ataxias should implement quality assurance measures as defined by the ADNI or other consortia. MRI protocols should allow morphometric analyses.

Spinocerebellar ataxia type 3/Machado-Joseph disease starting before adolescence

Onset of Machado-Joseph disease (SCA3/MJD) before adolescence has been rarely reported. This study aims to describe a cohort of SCA3/MJD with onset before 12 years of age, comparing their disease progression with the progression observed in patients with usual disease onset. We identified all cases from our cohort whose onset was before adolescence. After consent, patients were examined with clinical scales Scale for the Assessment and Rating of Ataxia (SARA) and Neurological Examination Score for Spinocerebellar Ataxia (NESSCA). Gender, age, age at onset, disease duration, CAG expanded repeats, transmitting parent, and anticipation of cases with infantile and adult onset were studied. Progression of NESSCA and SARA scores was estimated through a mixed model, and was compared with a historical group with onset after adolescence. Between 2000 and 2014, 461 symptomatic individuals from our region were diagnosed as SCA3/MJD. Onset of eight cases (2.2%), all heterozygotes, was before adolescence: seven were females (p = 0.054). CAG expanded repeats--75 ± 3 versus 84 ± 4--and anticipations--7 ± 9.7 versus 14.4 ± 7.2 years--were different between early childhood and adult onset groups (p < 0.03). The median survival of early childhood onset group was 23 years of age. The annual progression of SARA--2.3 and 0.6 points/year (p = 0.001)--and NESSCA--2.04 and 0.88 points/year (p = 0.043)--was faster in childhood than in adult onset group. Onset of SCA3/MJD before adolescence was related to larger expanded CAG repeats in heterozygosis; females seemed to be at higher risk. Disease progression was faster than in SCA3/MJD starting after 12 years.

Reliability of phenotypic early-onset ataxia assessment: a pilot study

AIM

To investigate the interobserver agreement on phenotypic early-onset ataxia (EOA) assessment and to explore whether the Scale for Assessment and Rating of Ataxia (SARA) could provide a supportive marker.

METHOD

Seven movement disorder specialists provided independent phenotypic assessments of potentially ataxic motor behaviour in 40 patients (mean age 15y [range 5-34]; data derived from University Medical Center Groningen medical records 1998-2012). We determined interobserver agreement by Fleiss' kappa. Furthermore, we compared percentage SARA subscores ([subscore/total score]×100%) between 'indisputable' (primary ataxia recognition by at least six observers) and 'mixed' (ataxia recognition, unfulfilling 'indisputable' criteria) EOA phenotypes.

RESULTS

Agreement on phenotypic EOA assessment was statistically significant (p<0.001), but of moderate strength (Fleiss' kappa=0.45; 95% CI 0.38-0.51). During mild disease progression, percentage SARA gait subscores discriminated between 'indisputable' and 'mixed' EOA phenotypes. In patients with percentage SARA gait subscores >30%, primary ataxia was more frequently present than in those with subscores <30% (p=0.001).

INTERPRETATION

Among movement-disorder professionals from different disciplines, interobserver agreement on phenotypic EOA recognition is of limited strength. SARA gait subscores can provide a supportive discriminative marker between EOA phenotypes. Hopefully, future phenotypic insight will contribute to the inclusion of uniform, high-quality data in international EOA databases.

Executive function deficits in pediatric cerebellar tumor survivors

BACKGROUND AND AIMS

Besides motor function the cerebellum subserves frontal lobe functions. Thus, we investigated executive functions in pediatric posterior fossa tumor survivors.

METHODS

We tested information processing, aspects of attention, planning and intelligence in 42 pediatric posterior fossa tumor survivors (mean age 14.63 yrs, SD 5.03). Seventeen low-grade tumor patients (LGCT) were treated with surgery only and 25 high-grade tumors patients (HGCT) received postsurgical adjuvant treatment. We evaluated simple reaction time, executive functioning, i.e. visuospatial memory, inhibition, and mental flexibility using the Amsterdam Neuropsychological Tasks program, whereas forward thinking was assessed with the Tower of London-test. Intelligence was determined using the Wechsler Intelligence Scale. Ataxia was assessed with the International Cooperative Ataxia Rating Scale.

RESULTS

About one third of each patient group showed forward thinking scores below one standard deviation of the norm. Impaired forward thinking correlated significantly with degree of ataxia (r = -0.39, p = 0.03) but not with fluid intelligence. Both patient groups exhibited executive function deficits in accuracy and reaction speed in more difficult tasks involving information speed and attention flexibility. Still, HGCT patients were significantly slower and committed more errors. Working memory was inferior in HGCT patients.

CONCLUSION

Pediatric cerebellar tumor survivors with different disease and treatment related brain damage exhibit similar patterns of impairment in executive functioning, concerning forward thinking, inhibition and mental flexibility. The deficits are larger in high-grade tumor patients. The pattern of function loss seen in both groups is most probably due to comparable lesions to cerebro-cerebellar circuits that are known to modulate critical executive functions.

Phosphomannomutase deficiency (PMM2-CDG): ataxia and cerebellar assessment

BACKGROUND

Phosphomannomutase deficiency (PMM2-CDG) is the most frequent congenital disorder of glycosylation. The cerebellum is nearly always affected in PMM2-CDG patients, a cerebellar atrophy progression is observed, and cerebellar dysfunction is their main daily functional limitation. Different therapeutic agents are under development, and clinical evaluation of drug candidates will require a standardized score of cerebellar dysfunction. We aim to assess the validity of the International Cooperative Ataxia Rating Scale (ICARS) in children and adolescents with genetically confirmed PMM2-CDG deficiency. We compare ICARS results with the Nijmegen Pediatric CDG Rating Scale (NPCRS), neuroimaging, intelligence quotient (IQ) and molecular data.

METHODS

Our observational study included 13 PMM2-CDG patients and 21 control subjects. Ethical permissions and informed consents were obtained. Three independent child neurologists rated PMM2-CDG patients and control subjects using the ICARS. A single clinician administered the NPCRS. All patients underwent brain MRI, and the relative diameter of the midsagittal vermis was measured. Psychometric evaluations were available in six patients. The Mann-Whitney U test was used to compare ICARS between patients and controls. To evaluate inter-observer agreement in patients' ICARS ratings, intraclass correlation coefficients (ICC) were calculated. ICARS internal consistency was evaluated using Cronbach's alpha. Spearman's rank correlation coefficient test was used to correlate ICARS with NPCRS, midsagittal vermis relative diameter and IQ.

RESULTS

ICARS and ICARS subscores differed between patients and controls (p < 0.001). Interobserver agreement of ICARS was "almost perfect" (ICC = 0.99), with a "good" internal reliability (Cronbach's alpha = 0.72). ICARS was significantly correlated with the total NPCRS score (rs 0.90, p < 0.001). However, there was no agreement regarding categories of severity. Regarding neuroimaging, inverse correlations between ICARS and midsagittal vermis relative diameter (rs -0.85, p = 0.003) and IQ (rs -0.94, p = 0.005) were found. Patients bearing p.E93A, p.C241S or p.R162W mutations presented a milder phenotype.

CONCLUSIONS

ICARS is a reliable instrument for assessment of PMM2-CDG patients, without significant inter-rater variability. Despite our limited sample size, the results show a good correlation between functional cerebellar assessment, IQ and neuroimaging. For the first a correlation between ICARS, neuroimaging and IQ in PMM2-CDG patients has been demonstrated.

Inter-rater reliability and validity of two ataxia rating scales in children with brain tumours

OBJECTIVES

This study aimed to investigate the inter-rater reliability and construct validity of the Scale for the Assessment and Rating of Ataxia (SARA) and Brief Ataxia Rating Scale (BARS) in children with posterior fossa tumours. These scales have been developed for adults with genetic ataxias, and the performance of these scales in children with brain tumours has not previously been described.

METHODS

The participants, who had undergone surgical resection for a posterior fossa tumour (inclusion criteria age 4-18 years), were recruited from the neuro-oncology service at a tertiary children's hospital. Children were assessed using the SARA, BARS and Paediatric Evaluation of Disability Index (PEDI) mobility domain, a measure of function. Children were independently rated by two therapists to determine the inter-rater reliability of the SARA and BARS. The construct validity was determined by assessing the correlation between the two scales with the PEDI.

RESULTS

Forty-four children were recruited. Inter-rater reliability was good for both scales, demonstrating the strong correlations (SARA, r = 0.94; BARS, r = 0.91) and the good consistency (93 % of SARA and 90 % of BARS paired scores differing by less than 2 points) between two raters. Both ataxia scales demonstrated a strong negative correlation with the mobility domain of the PEDI (SARA, r = -0.77; BARS, r = -0.76), indicating that more severe ataxia was associated with worse mobility. The mean time for completion of the SARA was 4.5 and 2.7 min for the BARS.

CONCLUSIONS

The SARA and BARS are reliable and valid measures and appear to be of equal value in determining the severity of ataxia in children with posterior fossa tumours.

Robotic and clinical evaluation of upper limb motor performance in patients with Friedreich's Ataxia: an observational study

BACKGROUND

Friedreich's ataxia (FRDA) is the most common hereditary autosomal recessive form of ataxia. In this disease there is early manifestation of gait ataxia, and dysmetria of the arms and legs which causes impairment in daily activities that require fine manual dexterity. To date there is no cure for this disease. Some novel therapeutic approaches are ongoing in different steps of clinical trial. Development of sensitive outcome measures is crucial to prove therapeutic effectiveness. The aim of the study was to assess the reliability and sensitivity of quantitative and objective assessment of upper limb performance computed by means of the robotic device and to evaluate the correlation with clinical and functional markers of the disease severity.

METHODS

Here we assess upper limb performances by means of the InMotion Arm Robot, a robot designed for clinical neurological applications, in a cohort of 14 children and young adults affected by FRDA, matched for age and gender with 18 healthy subjects. We focused on the analysis of kinematics, accuracy, smoothness, and submovements of the upper limb while reaching movements were performed. The robotic evaluation of upper limb performance consisted of planar reaching movements performed with the robotic system. The motors of the robot were turned off, so that the device worked as a measurement tool. The status of the disease was scored using the Scale for the Assessment and Rating of Ataxia (SARA). Relationships between robotic indices and a range of clinical and disease characteristics were examined.

RESULTS

All our robotic indices were significantly different between the two cohorts except for two, and were highly and reliably discriminative between healthy and subjects with FRDA. In particular, subjects with FRDA exhibited slower movements as well as loss of accuracy and smoothness, which are typical of the disease. Duration of Movement, Normalized Jerk, and Number of Submovements were the best discriminative indices, as they were directly and easily measurable and correlated with the status of the disease, as measured by SARA.

CONCLUSIONS

Our results suggest that outcome measures obtained by means of robotic devices can improve the sensitivity of clinical evaluations of patients' dexterity and can accurately and efficiently quantify changes over time in clinical trials, particularly when functional scales appear to be no longer sensitive.