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F56 Quantifying fine-motor impairment in ataxia: digital parameters of q-motor spiral drawing correlate with clinical severity, function & ADLs – lessons for HD
  1. Robin Schubert1,
  2. Dominik Hermle2,3,
  3. Pascal Barallon1,
  4. Rebecca Schüle2,3,
  5. Ralf Reilmann1,2,4,
  6. Matthis Synofzik2,3,
  7. Andreas Traschütz2,3
  1. 1George Huntington Institute, Münster, Germany
  2. 2Hertie Institute for Clinical Brain Research, University of Tübingen, Tübingen, Germany
  3. 3German Center for Neurodegenerative Diseases (DZNE), University of Tübingen, Tübingen, Germany
  4. 4Department of Clinical Radiology, University of Münster, Münster, Germany


Background and Objective Upper-limb function is insufficiently explored as digital-motor outcome in ataxia. The Archimedes spiral-drawing-task might serve as a meaningful outcome requiring fine-motor skills of everyday-living. We implemented Archimedes-spiral-drawing in the trial-ready quantitative-motor (Q-Motor) system and explored underlying movement kinematics as digital outcomes.

Methods Cross-sectional single-center validation study in 46 patients with predominantly degenerative cross-genotype cerebellar-ataxias (mean-age: 50 years; mean-SARA: 12 points), and 48 age- and sex-matched controls. Subjects were instructed to draw – as accurate as possible at self-paced speed - two Archimedes spirals with their dominant hand on a paper template while traced by a Polhemus FASTRAK digitizer with a pencil lead attachment. Thirty-five parameters were validated against the Scale for the assessment and rating of ataxia (SARA), activities of daily living (FARS ADL), and the 9-hole peg-test (9HPT).

Results Parameters in the spatial domain, namely the summed 10th decile, standard deviation and maximum of the error distribution (distance from template), discriminated best between ataxia and controls (AUC: 0.83-0.89), and showed the strongest correlation with FARS-ADL (rho: 0.38-0.47). In contrast, parameters in the frequency (Fourier power, 1-4 Hz, Spearman rho: 0.75) and spatiotemporal domain (90th percentile of speed, rho: 0.72) correlated most with the total SARA (specifically a composite of upper-limb items), as well as the 9HPT (rho: 0.59-0.74).

Discussion and Conclusion Quantitative analysis of Archimedes-spiral-drawing allows to capture fine-motor impairment, with differential correlations to clinical severity, function, and ADL across domains in ataxia – encouraging its exploration in HD. Longitudinal analyses are ongoing to investigate sensitivity to change.

  • Q-Motor
  • quantitative assessment
  • clinical trials
  • ataxia

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