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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., (© 2019 The Authors. Developmental Medicine & Child Neurology published by John Wiley & Sons Ltd on behalf of Mac Keith Press.)

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., (Copyright © 2018. Published by Elsevier Ltd.)

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.

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., (© 2017 Mac Keith Press.)

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., (© 2016 Mac Keith Press.)

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., (Copyright © 2016 Elsevier B.V. All rights reserved.)

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., (© 2015 Mac Keith Press.)

Aim: The aim of the study was to determine whether paediatric ataxia speech subscores are reliably applicable for international early-onset ataxia (EOA) databases. If so, we reasoned that ataxia speech subscores should be associated with ataxia scores and involve high interobserver agreement, including those for internationally applicable Scale for Assessment and Rating of Ataxia (SARA) syllable repetition tasks (SARASRT)., Method: Three independent paediatric neurologists and a speech therapist scored speech in 52 healthy children (mean age 10y, range 4-16y) and 40 individuals with EOA (mean age 15y, range 5-34y). We compared ataxia speech subscores for the association with age and ataxia scores as well as interobserver reliability., Results: In healthy children, ataxia speech subscores were moderately associated with age (International Cooperative Ataxia Rating Scale [ICARS]: r=-0.515; SARA: r=-0.321; p<0.05) and with ataxia scores (ICARS: r=0.552; SARA: r=0.336; p<0.05), and revealed slight to moderate interobserver agreement (ICARS-intraclass correlation coefficient [ICC]: 0.380; SARA-ICC: 0.185; SARASRT-ICC: 0.509). In EOA, speech subscores have a strong association with ataxia scores (ICARS: r=0.735; SARA: r=0.730; p<0.001) and revealed substantial to nearly perfect interobserver agreement (ICARS-ICC: 0.812; SARA-ICC: 0.854; SARASRT-ICC: 0.724)., Interpretation: Early-onset ataxia speech subscores are associated with ataxia and also reveal high interobserver agreement, including those internationally applicable to SARASRT. We conclude that SARASRT appears to be applicable for EOA databases. However, before syllable repetition tasks are included, we would advise to wait for the results published by the international Childhood Ataxia and Cerebellar Group., (© 2014 Mac Keith Press.)