Rating ataxia using video capture: the development of the SARAhome assessment
A particular highlight of our webinar, Video Capture for Patient-Centered Clinical Trials, this article features Dr Marcus Grobe-Einsler MD of Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE, the German Centre for Neurodegenerative Diseases) and the story behind digitising the Scale for the Assessment and Rating of Ataxia, SARA, into SARAhome.
What is SARAhome?
SARAhome is a digital assessment of ataxia at home. Ataxias are a heterogeneous group of rare movement disorders and the core clinical features of these disorders are progressive gait disturbance, impaired coordination and speech disturbance.
“We usually see our patients once a year at least, and we need some kind of objective measurement for the severity of ataxia. SARA, the scale for assessment and rating of ataxia, is established as the golden standard in the examination of ataxic patients, it’s been broadly validated, we all use it, and we have a lot of information about reliability, validity, linearity, sensitivity to change,” says Marcus.
“What we actually do with the patients when applying SARA is we assess gait, standing, sitting, speech disturbance, finger chase nose-finger tests, fast alternating hand-movements and a heel-shin slide test.”
The severity of each symptom is rated on a point scale, which is differently weighted depending on how severe the functional impairment is for these patients in their daily life.
Limitations of in-clinic assessments
Ataxia patients experience fluctuations in the severity of their ataxia during everyday life, and they report that. But we cannot measure it, because we only have this snapshot visit. “So we see them once a year and it’s really hard to get more information about these fluctuations,” says Marcus “because we can only ask them, but don’t have a home assessment.”
Marcus continued, “SARA is a very useful instrument, but we know that there are limitations to it. And the most important limitation is that it takes place in a clinical setting so we don’t get the information about the situation at home, that real-life data. And you have the necessity of an investigator, so you always need to have to travel for one of those persons.”
If the patient comes to the clinic, or even if the doctor comes to the patient once a year, there is very little (or even zero) information about daily fluctuations in severity.Dr Marcus Grobe-Einsler, DZNE
So Marcus’s team went back to the original SARA score and tried to identify those items that the patient would be able to perform by themselves after instruction by investigators. They settled on:
- Speech disturbance
- Fast Alternating Movement
“We identified those five items to keep and we eliminated the sitting and the heel shin slide because they’re less feasible at home. Patients would have to climb on a high chair or lie down for these items. We also eliminated the finger chase, just for the obvious reason that for the moving target we’d need a second person at home. We included standardised speech that is not included in the original SARA score but delivers a lot of information that we can use for the development of automatic ratings.”
“One question we had to answer was: can we eliminate three items (from SARA) without destroying what the score tells us about the severity of ataxia?”
The original SARA publication from 2006 in part answered this question as the internal consistency is high in this score, meaning that if you eliminate an item it doesn’t really destroy the meaning of the score.
DZNE wanted more information about that so they used data from a closed retrospective study, the EUROSCA trial, including patients with spinocerebellar ataxia types one, two, three, and six – these are autosomal dominantly inherited disorders, with ataxia as a core feature – and looking at the SARA scores from the baseline and comparing those with the extraction of only those items used for SARAhome showed a very high correlation between those scores.
Marcus points out, “But we, of course, need to demonstrate this, so high correlation always means that you have a narrow distribution of those points here (around the line). At this point, we also wanted to develop some kind of help for the patients when they use it at home.”
This led to the development of the SARAhome assessment in Aparito’s Atom5TM clinical trial platform.
Developing SARAhome in Atom5TM
“We started cooperation with Aparito to develop the app version of SARAhome. We created written instructions and instructional videos that are implemented in the app that guide patients through the task performance.”
The app allows recording of these assessments at home and, most importantly, secure data transfer of those videos for rating by experienced investigators.
“One advantage that we see here is that we can be flexible in combination with other PROs as it’s a modular system”, says Marcus “and we can easily add a questionnaire if we need one. The app also automatically sends out reminders for upcoming assessments.”
Validation of SARAhome
The DZNE team subsequently went into the prospective validation phase and recruited 50 patients with mixed cerebellar ataxia; not only spinocerebellar ataxia but any disease that impacts the cerebellum. ”We performed a conventional SARA score on these patients and then we instructed the patients to record a SARAhome score on their own. We had an experienced investigator that was not involved in this assessment to rate the videos of the SARAhome.”
This provided a video rating of SARAhome versus a conventional SARA score in the same study for a head to head comparison and there was a very high correlation between those two scores.
“So,” continues Marcus, “we have a validated score, but what we actually want to do is measure fluctuations and show that the score actually works. We recruited additional patients and asked them to continue recording SARAhome for 14 days; once in the morning, once in the evening.”
The results brought into sharp relief two findings:
- 14 days is a long period of time and applies a significant burden to patients. The DZNE team’s analysis of their data concluded that five days of assessment may be sufficient (pending confirmation via a larger cohort).
- an average SARAhome score from five days of assessments provides a more meaningful measure and severity of ataxia than a conventional snapshot visit conducted once a year.
“So,” declared Marcus, “we have a validated home-based digital assessment of ataxia with SARAhome. We demonstrated the feasibility, safety and acceptance in a pilot study. And SARAhome is implemented in Aparito’s Atom5TM app and is available for immediate use.
We asked what was next for Marcus. He responded, “We have ongoing and future studies investigating the effects of the fluctuations. We want to see these effects in a higher number of patients in a genetically homogeneous population in spinocerebellar ataxia type three in a multicentric setting and want to investigate the reasons for why we see these fluctuations.”
To learn more about the fantastic work of DZNE please visit them at www.dzne.de/en/.
Four benefits of video assessments
1. Video promotes comparability – video assessments reduce inter-rater reliability because a video assessment means that clinicians score the same investigation with a centralised grading.
2. A large number of recordings – at-home assessments provide information about disease burden in real-world settings.
3. Increased frequency of assessments – video capture can help study the therapeutic effects of interventions and measure fluctuations by asking for assessments to be carried out twice or thrice daily
4. Reviewing an assessment – we can replay a video, we can pause it, or we can slow it down, allowing us to study an assessment in ways that is not feasible with in-clinic assessments