The European PROSPAX Consortium have shared results from their 8-week remote study of the SPAX smartphone app for tracking symptoms in spastic ataxias.
About the PROSPAX project
The PROSPAX consortium of patient groups, researchers and clinicians across Europe and Canada (including the UK), set up the PROSPAX project to study the progression of spastic ataxias over time, in a rigorous and harmonised way – from the clinical to the molecular level. This has included clinical, imaging, digital-motor and molecular markers of progression and animal models. As the numbers of people with these specific ataxias are quite low, this harmonisation across countries is necessary to gather enough information about the conditions, helping to prepare for clinical treatment trials. This is called ‘trial-readiness’ and is extremely important for rare conditions.
Digital measures of disease progression
Digital measures of disease progression have shown potential as outcome measures to test the effectiveness of a drug or intervention in clinical trials. Digital measures can capture people’s daily functioning and symptom variability, which can be missed in clinical assessments. However, research looking at digital measures in the home environment is limited. Use of wearable sensors can be expensive and impractical. These researchers proposed a smartphone app given the widespread use of smartphones which have in-built sensors.
How the study was carried out
This study looked at the feasibility of a mobile phone app called the SPAX app. The app contains four tasks assessing gait, standing balance, finger and hand movement, along with a questionnaire about the severity of their symptoms. The researchers recruited 38 participants with spastic ataxias (ARSACS and SPG7) and 10 healthy people without ataxia (known as controls). They looked at how well participants adhered to using it over an 8-week period and how well they performed the different tasks at different times of the day.
Participants first answered questions from the questionnaire and performed the tasks in the clinic during a training session with the SPAX app. Then, the severity of their ataxia and spasticity were assessed by a clinician using clinical rating scales (including the Scale for Assessment and Rating of Ataxia, SARA). Participants then performed the tasks and answered the questionnaire twice a week in the morning and evening at home. The choice of morning and evening was to account for the fact that fatigue can occur throughout the day.
Results of the study
Participants found that using the app was practical and achievable for finger and hand movement tasks (92%), but less so for gait (47%) and stance tasks (63%). Among participants who were able to complete the tasks, 81% adhered to the study protocol. There was no significant difference between the morning and evening measures for most of the tasks apart from the finger movement task, which was notably different in participants with spastic ataxia. This indicates that motor functions are consistent through the day. The measures from the app correlated well with the measures taken by clinicians using clinical rating scales.
For the tasks measuring gait, 15% of participants with spastic ataxia had difficulty following the instructions for the task or were unable to complete it, and for the stance task this was 25%. This points to the challenges of completing the tasks in ab unsupervised home environment.
Overall, the study found that the SPAX app is a reliable and practical tool for at-home monitoring of motor functions in spastic ataxias. As this study was carried out over only 8 weeks, longer-term studies will be needed to assess the clinical relevance of the SPAX app for potential use in clinical trials for spastic ataxias. Future work will focus on optimising the tasks especially for measuring gait and stance to ensure participants can complete them and they are able to measure function sensitively.
Read the paper here.
Read more about the SPAX app in an interview with one the researchers who developed it, Ilse Willemse, here.
Read more about PROSPAX here.