T.F. Lawerman

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

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.

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

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.

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

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

Assessment of speech in early-onset ataxia: a pilot study

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).

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 classifiers 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.

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 (SARAGAIT/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 SARAGAIT/POSTURE sub-scores by three independent pediatric neurologists. For convergent validity, we associated SARAGAIT/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 (SARAKINETIC; kinetic function of the upper and lower limbs), (5) Archimedes Spiral (AS; kinetic function of the upper limbs), and (6) total SARA scores (SARATOTAL; i.e., summed SARAGAIT/POSTURE, SARAKINETIC, and SARASPEECH sub-scores). For discriminant validity, we investigated whether EOA co-morbidity factors (myopathy and myoclonus) could influence SARAGAIT/POSTURE sub-scores. Results: The inter-observer agreement (ICC) on EOA SARAGAIT/POSTURE sub-scores was high (0.97). SARAGAIT/POSTURE was strongly correlated with the other ataxia and functional scales [ASMK (rs = -0.819; p < 0.001); PBS (rs = -0.943; p < 0.001); GMFCS-E&R (rs = -0.862; p < 0.001); SARAKINETIC (rs = 0.726; p < 0.001); AS (rs = 0.609; p = 0.002); and SARATOTAL (rs = 0.935; p < 0.001)]. Comorbid myopathy influenced SARAGAIT/POSTURE scores by concurrent muscle weakness, whereas comorbid myoclonus predominantly influenced SARAKINETIC scores. Conclusion: In young EOA patients, separate SARAGAIT/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 SARAGAIT/POSTURE scores for comorbid muscle weakness.

OP60 – 2351: Reliability and discriminant validity of ataxia rating scales in early onset ataxia

Objectives In children and young adults, Early Onset Ataxia (EOA) is frequently concurrent with other movement disorders, resulting in moderate inter-observer agreement among movement disorder professionals. To investigate whether phenotypic steps are replaceable by quantitative measures, we aimed to determine inter-observer agreement and discriminant validity of ataxia rating scales. Methods In 40 EOA patients (15 (5–34) years; mean (range)), three independent pediatric neurologists assessed quantitative ataxia rating scales (ICARS, SARA and BARS), and phenotyped the primary movement disorder characteristic (i.e. ataxic, dystonic, myoclonic, chorea, tics) in each patient. We determined inter- and intra-observer agreement and specified outcomes for “primary” (i.e. primary ataxia identification by all assessors and/or identified ataxic diagnosis (n=26)) and “secondary” (i.e. incomplete identification of ataxia as the primary movement disorder (n=12)) subgroups. Results Inter- and intra-observer agreement of ataxia rating scales revealed high intra-class correlation coefficients (ICC: 0.92–0.99; for ICARS, SARA and BARS), with no significant differences between “primary” and “secondary” subgroups. Total ataxia rating scale scores revealed higher outcomes in the “primary” than the “secondary” subgroup (p Conclusions In EOA, quantitative rating scales reveal high inter- and intra-observer reliability, reflecting reliable applicability. However, multivariable regression analysis revealed low discriminant validity between ataxia and other movement disorder characteristics. Despite high reliability of quantitative ataxia scores, these data implicate that preceding phenotypic characterization remains irreplaceable.

PP12.14 – 2319: Reliability of phenotypic early onset ataxia recognition

Objective In absence of a “golden detection standard”, identification of early onset ataxia (EOA) relies on phenotypic ataxia recognition. In children, this process is complex for several reasons: 1. physiologically immature motor behavior may “overlap” with signs of initiating ataxia; 2. EOA often involves “mixed” phenotypes (i.e. concurrent with other movement disorders) and 3. movement disorders are phenotyped by specialists of diverse backgrounds. Insight in phenotypic EOA recognition may help to improve the diagnostic yield of innovative genetic techniques and may contribute to the inclusion of high quality patient data in international databases. This study aimed to investigate the inter-observer agreement on phenotypic EOA recognition and to explore whether SARA (Scale for Assessment and Rating of Ataxia) can provide a discriminative marker for EOA recognition. Methods Seven movement disorder specialists independently phenotyped motor behavior of 40 patients (mean age 15 years, range 5–34 years) in whom ataxic features were described (medical records; University Medical Center Groningen; 1998–2012). We determined Fleiss Kappa (FK) and Cohens Kappas according to observer-subgroups (pediatric-neurology, adult-neurology, genetics, and trainees). We compared %SARA-subscores (subscore/total score x 100%) between “indisputable” (primary ataxia recognition by at least six observers) and “mixed” (ataxia recognition, unfulfilling “indisputable” criteria) EOA phenotypes. Results Phenotypic EOA recognition was statistically significant, but of moderate strength (FK=0.414). Pediatric neurologists revealed the highest intergroup agreement (with all observer-subgroups; p Conclusion Among movement disorder professionals from different disciplines, inter-observer agreement on phenotypic EOA recognition is statistically significant, but of moderate strength. SARA gait-subscores can provide a supportive discriminative marker between EOA phenotypes. Phenotypic insight may hopefully contribute to the inclusion of uniform, high quality data in international EOA databases.