An observational study in Friedreich Ataxia, sponsored by University of Exeter. Not yet recruiting at 1 site in United Kingdom. Open to participants aged 12 Years to 50 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-07-28.
Sponsored by University of Exeter · Observational
Friedreich ataxia (FA) is a rare, inherited condition that progressively affects balance, coordination, and walking. Clinical trials of new FA treatments rely largely on standard clinical rating scales, but these can be tiring for patients, feel disconnected from everyday life, and may not detect small but meaningful changes over time. More objective, sensitive, and patient-relevant ways of measuring movement are needed.
This study is developing and testing a new digital way of measuring movement in FA. Participants play short, movement-based computer games on a laptop while a single camera and artificial-intelligence (AI) software track how they move. The proposition is that the way a person plays these games - their speed, accuracy, and movement quality - can provide objective, meaningful measurements of motor function. In the laboratory, these game-based measurements are compared against a "gold-standard" full-body motion-capture system and against established clinical scales to check how accurate and meaningful they are.
The study involves both people with Friedreich ataxia (across a range of disease severity) and healthy volunteers. People with FA also take part in a 12-week home phase, playing the games at home each month with remote support, so the researchers can examine whether the digital measurements are reliable when repeated and whether they can detect change over time.
The study asks whether these digital, game-based movement measurements are reliable, valid, and sensitive enough to be used as a "fit-for-purpose" digital clinical outcome assessment (dCOA) in future FA clinical trials, and whether patients find the platform acceptable, usable, and relevant to daily life. This is an early-stage feasibility and validation study designed to establish proof of concept rather than to test the effectiveness of a treatment.
Design and rationale STEP-OUT FA is an observational, prospective cohort study (STROBE-compliant) developing and validating a digital clinical outcome assessment (dCOA) for Friedreich ataxia. It addresses a well-documented limitation in FA therapeutic development: existing semi-quantitative clinical outcome assessments are affected by floor and ceiling effects, limited responsiveness across disease stages, and poor patient-perceived relevance, which have contributed to repeated failures of drug trials to meet primary endpoints. The study evaluates whether motor-performance metrics captured during gamified, semi-immersive virtual-reality (VR) tasks, combined with markerless AI motion analysis, can serve as reliable, valid, and responsive outcome measures.
Measurement platform The platform is delivered through a standard laptop and integrates three components: (1) FA-adaptable VR gamified tasks (e.g., ball catching, target reaching) with adjustable difficulty; (2) automated extraction of gaming-performance metrics; and (3) a single-camera, patented AI-driven markerless motion-capture system for 3D pose reconstruction (DigiTherapix Ltd), used to derive biomechanical/kinematic metrics. The gaming environment is provided via the MoveHero platform (University of São Paulo).
Laboratory validation (healthy controls and FA participants) Validation is conducted at the University of Exeter VSimulator facility against a gold-standard, marker-based full-body motion-capture reference. During a single laboratory visit (\~2 hours), participants complete a familiarisation period followed by a \~20-minute session of four movement-based gaming tasks. Concurrent signals are recorded throughout: full-body optical motion capture (reflective markers on shoulders, elbows, knees, ankles, forehead), continuous heart-rate variability via a Delsys ECG sensor (baseline, task, recovery), and functional near-infrared spectroscopy (fNIRS) over the forehead to index cortical activation. Perceived exertion and fatigue (Borg RPE and Borg VAS Fatigue) are collected after each task, and a short semi-structured interview captures usability and acceptability feedback (audio-recorded for later transcription). FA participants additionally complete clinical characterisation at baseline.
Home-based longitudinal phase (FA participants only) To evaluate test-retest reliability and responsiveness, FA participants enter a 12-week home phase with monthly self-administered or remotely supported gaming sessions (\~20-30 minutes) at Weeks 4, 8, and 12, each accompanied by a brief telehealth check-in with a physiotherapist to confirm continued consent, provide support, and monitor adverse events. Data are captured automatically and remotely. A remote follow-up assessment at Week 12 repeats clinical and patient-reported measures and includes a short interview.
Analytic approach Concurrent validity is assessed via correlations between digital metrics and established clinical scales; reliability via intraclass correlation coefficients across repeated sessions; and responsiveness via within-subject change and effect sizes, with longitudinal mixed-effects modelling of dCOA trajectories across the home-phase time points. Analyses characterise which individual or composite metrics (gaming-derived versus biomechanical) show optimal measurement properties and best discriminate disease severity. As an exploratory feasibility and validation study establishing proof of concept and psychometric properties, no formal power calculation was performed; the sample size was justified on precision for reliability estimation and on precedent from rare-disease dCOA validation studies.
Collaborators and data governance The AI motion-analysis platform is provided by DigiTherapix Ltd (UK) and the gaming platform by the University of São Paulo (Brazil); formal sub-contractor and data-sharing agreements govern intellectual property and data governance. No personally identifiable participant data are transferred outside the UK. Oxford University Hospitals acts as a Participant Identification Centre only.
110 studies on the registry are indexed under Friedreich Ataxia; 27 are open to participants now.
This study's planned enrollment of 40 is below the median of 70 across 31 observational studies indexed under Friedreich Ataxia.
Browse Friedreich Ataxia studies →University of Exeter is the lead sponsor of 140 studies on the registry; 25 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Study participants with FA spanning a range of disease severity and functional mobility, recruited across England, together with healthy volunteers of the same age range serving as a comparison group.
Friedreich ataxia group:
Healthy control group:
Exclusion Criteria:
Healthy control group:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants aged 12-50 with genetically confirmed FA (homozygous GAA expansion or compound heterozygous FXN mutations). Complete the laboratory validation session and a 12-week home-based phase with monthly gaming sessions.
Device: Laboratory validation session (VSimulator) · Device: Home-based active gaming assessment
Participants aged 12-50 without FA, providing reference data for validation. Complete the laboratory validation session only.
Device: Laboratory validation session (VSimulator)
Single laboratory visit at the University of Exeter VSimulator in which VR active gaming tasks and single-camera AI-driven markerless motion analysis are performed concurrently with gold-standard marker-based full-body motion capture, functional near-infrared spectroscopy (fNIRS), and continuous heart-rate variability (Delsys ECG sensor). Performed once.
Monthly home-based sessions (Weeks 4, 8, 12) in which participants perform the VR active gaming tasks with concurrent single-camera AI-driven markerless motion analysis via a loaned laptop, with automated remote data capture. No marker-based motion capture, fNIRS, or ECG.
Concurrent validity of game-based movement performance against the mFARS - Friedreich ataxia cohort.
Spearman correlation coefficient (ρ; unitless) between game-based movement accuracy (Absolute Error), precision (Variable Error), reaction time, movement time and the modified Friedreich's Ataxia Rating Scale (mFARS) total score (range 0-93; higher = greater neurological impairment), in the Friedreich ataxia cohort.
Time frame: Baseline laboratory visit (Week 0)
Criterion validity of AI markerless motion capture versus marker-based motion capture - Healthy Controls and Friedreich Ataxia
Agreement for upper and lower body angular velocity, joint angles and functional range of motion measured concurrently by the single-camera AI markerless system and the gold-standard marker-based motion-capture system.
Time frame: Baseline laboratory visit (Week 0)
Comparison of the digital COA metrics between healthy control and Friedreich ataxia cohort.
Use of VR game-derived digital metrics (reaction time, movement time, movement accuracy and precision, and AI-derived kinematic metrics such as angular velocity, joint angles and Functional Range of Motion) to compare healthy control and Friedreich ataxia cohort.
Time frame: Baseline laboratory visit (Week 0)
Responsiveness of digital COA metrics over time
Within-subject change scores and effect sizes for digital metrics, analysed with longitudinal mixed-effects modelling of dCOA trajectories across the home-based phase.
Time frame: Weeks 0, 4, 8, and 12
Patient Global Impression of Change (PGIC)
Patient Global Impression of Change, 7-point ordinal scale (1 = very much improved to 7 = very much worse; higher = greater perceived worsening), in the FA cohort.
Time frame: Week 12
Platform acceptability and usability
System Usability Scale (SUS) total score (range 0-100; higher = better usability; ≥70 acceptable, ≥80 excellent).
Time frame: Weeks 0, 4, 8, and 12
Cortical activation during gaming tasks (fNIRS) - healthy control and Friedreich ataxia cohort.
Changes in cortical haemodynamic response (oxygenated and deoxygenated haemoglobin) measured by functional near-infrared spectroscopy during the gaming session.
Time frame: Baseline laboratory visit (Week 0)
Autonomic response during gaming tasks (heart-rate variability) - healthy control and Friedreich ataxia cohort.
Heart-rate variability indices derived from continuous ECG recording (Delsys sensor) at baseline, during, and after the gaming session.
Time frame: Baseline laboratory visit (Week 0)
Perceived exertion (Borg CR10) - healthy control and Friedreich ataxia cohort.
Borg Rating of Perceived Exertion score (range 1-10; higher = greater exertion) after each gaming task.
Time frame: Baseline laboratory visit (Week 0)
Fatigue (Borg VAS Fatigue) - healthy control and Friedreich ataxia cohort.
Visual Analogue Scale (VAS) for fatigue (range 0-10; higher = greater fatigue) after each gaming task.
Time frame: Baseline laboratory visit (Week 0)
9-Hole Peg Test completion time - healthy control and Friedreich ataxia cohort.
Time to complete the 9-Hole Peg Test (9HPT), measured in seconds (higher = worse manual dexterity; no fixed maximum), averaged across the dominant and non-dominant hands, in the Friedreich ataxia cohort.
Time frame: Baseline laboratory visit (Week 0)
Gait quality: proportion of good steps (Heel2Toe sensor)
Proportion of "good steps" - steps in which the heel strikes first, detected by the Heel2Toe wearable sensor from ankle sagittal-plane angular velocity, expressed as a percentage of total steps taken during a standardised walking task (range 0-100%; higher = better gait quality), in the Friedreich ataxia cohort.
Time frame: Baseline laboratory visit (Week 0)
Plan to share: No
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