Cerebellar Ataxia

Objective coordination and intention tremor endpoints for ataxia trials

Cerebellar ataxia trials, including Friedreich ataxia and the spinocerebellar ataxias, rely on SARA and ICARS for regulatory precedent. NeuroQuantix adds continuous kinematic measurement of dysmetria, intention tremor, and spatial error from a brief spiral drawing, so that the upper-limb coordination component can be measured on its own rather than inside a composite.

Published evidence on digitized spiral analysis supports continuous, rater-independent motor measurement; the strength of that evidence for this condition is stated on this page. NeuroQuantix standardizes this evidence into a pre-specified endpoint for your program. Learn more about cerebellar ataxia from the NINDS/NIH overview.

Discuss Your Program View Technical Data

Continuous

Dysmetria Measurement

RMSE from ideal spiral and spiral width variability at 240 Hz

Spectral

Intention Tremor

Frequency and amplitude decomposition of pen velocity

None

Rater Dependence

Computed metrics, no observer scoring

Emerging

Evidence Status

Scoping review, Wang et al., 2025

Limitations of SARA

The The Scale for the Assessment and Rating of Ataxia (SARA) is the current gold standard for cerebellar ataxia assessment in clinical trials. These are its documented limitations.

SARA and ICARS provide the regulatory precedent and clinical interpretability that ataxia trials depend on

SARA scores gait, stance, sitting, speech, finger chase, nose-finger, fast alternating hand movements, and heel-shin as ordinal items; upper-limb coordination is a fraction of the total

Ordinal items compress small changes in dysmetria and intention tremor that a continuous spatial-error metric resolves

Rater-dependent scoring of finger-chase and nose-finger tasks introduces between-site variability in multi-site programs

Slowly progressive ataxias require high measurement precision to detect change within a trial window; continuous metrics add that precision beside SARA

Published spiral studies in ataxia populations report spatial variability indices that track cerebellar dysfunction, and the scoping review lists ataxia among the conditions with emerging, not yet extensive, evidence

The Ataxia Measurement Challenge

Ataxia programs face two constraints at once: slowly progressive disease and small populations. SARA and ICARS carry the regulatory precedent, but their upper-limb items are ordinal, rater-scored, and a small share of the composite. Gene therapy, antisense, and small-molecule programs in Friedreich ataxia and the spinocerebellar ataxias need a coordination measure precise enough to detect change within a trial window and in a cohort that may number in the dozens. Continuous spiral kinematics measure dysmetria and intention tremor directly and sit beside the scale as a pre-specified exploratory endpoint.

Clinical Applications

Friedreich ataxia gene therapy and small-molecule trials

Spinocerebellar ataxia antisense oligonucleotide programs

Natural history studies establishing upper-limb progression rates

Exploratory endpoint beside SARA in Phase 1/2 studies

Published Evidence

Evidence from peer-reviewed publications supporting digital kinematic endpoints for cerebellar ataxia assessment. View the full evidence base.

Spatial Variability Indices in Ataxia

Published spiral drawing studies in cerebellar ataxia populations report spatial variability metrics that separate patients from controls and correlate with clinical ataxia scales.

Scoping review: Wang S, et al. Movement Disorders Clinical Practice, 2025

Standardized Methodology

The NeuroQuantix methodology was standardized from the analysis in the scoping review, including device configuration, instruction scripting, and metric pre-specification, so that ataxia measurements are comparable across sites.

Wang S, et al. Movement Disorders Clinical Practice, 2025

Statistical Power Advantage

Higher measurement precision translates directly into smaller enrollment requirements. See the full interactive power curve comparison on the NeuroQuantix platform page.

View Power Visualization

Frequently Asked Questions

What are the limitations of SARA for cerebellar ataxia clinical trials?

SARA is an eight-item ordinal scale scored by a trained rater, so it carries inter-rater variability and compresses small changes. Upper-limb coordination contributes only a few items to the total, which dilutes a treatment effect on dysmetria or intention tremor. SARA remains the regulatory anchor; the opportunity is to add a continuous kinematic measure of upper-limb coordination beside it.

How does NeuroQuantix measure ataxia objectively?

A patient completes a brief spiral drawing on a tablet. The platform computes spatial error from the ideal spiral (RMSE), spiral width variability, intention tremor spectra, velocity irregularity, and smoothness at 240 Hz. These capture dysmetria and intention tremor as continuous variables that can be pre-specified as an exploratory or secondary endpoint alongside SARA or ICARS.

Is digital spiral analysis validated in Friedreich ataxia and spinocerebellar ataxia?

Published spiral drawing studies in ataxia populations report reliable spatial variability metrics that correlate with clinical scales, but the scoping review of 120 studies identified ataxia as an area with emerging rather than extensive evidence. NeuroQuantix is positioned for pre-specified exploratory endpoint use in ataxia trials, generating within-program evidence for the context of use.

Can an objective coordination endpoint help a small ataxia trial reach power?

Enrollment is set by measurement error, and rare ataxias cannot enroll their way out of a noisy endpoint. A continuous, rater-independent metric removes rater variance and ordinal compression from the measurement. The size of the gain for a specific program depends on the mechanism and the metric pre-specified, which is what a technical briefing works out.