In the current study, we introduce SARA-Le, a video conferencing (VC) protocol specifically designed for the remote assessment of ataxia severity. This protocol, which is derived from the original in-person open-access Scale for the Assessment and Rating of Ataxia (SARA), offers both time and cost-effectiveness as it can be easily administered in the participant’s home environment using only a computer, internet connection, and camera.

We conducted a prospective validation study of SARA-Le involving patients with cerebellar ataxia (CA). The results demonstrated significant associations between SARA-Le and conventional measures. First, we found a very high positive association between the SARA-Le and SARA scores, supporting the convergent validity. Additionally, the ICC between the SARA and the SARA-Le was high, supporting reliability. Second, we observed significant correlations between SARA scores and nine spatial–temporal gait measures, which are typical characteristics of ataxic gait patterns. Consistent with these results, the SARA-Le scores also exhibited significant correlations with the nine gait measures, providing an independent aspect of construct validity. Third, the SARA-Le Cronbach's Alpha value was high, demonstrating high internal consistency. Fourth, in line with previous findings collected using the in-person SARA [16, 19, 20], a positive correlation was found between SARA-Le scores and disease duration, supporting construct validity. Fifth, consistent with existing in-person literature [17, 18], the SARA-Le scores were negatively correlated with MoCA scores, supporting construct validity. Taken together, the pattern of results underscores the feasibility and validity of SARA-Le. This converging evidence strengthens the case for the broader adoption of SARA-Le in both clinical and research settings.

To date, ataxia severity has been assessed mostly in-person. However, there have been attempts to adapt SARA for remote assessment through leveraging technology-based tools [9–11, 20–24]. Yet, most of these tools required the use of additional equipment such as an accelerometer [21] handheld video cameras [22], tablet devices [10], or devices from video games such as Microsoft Kinect, Leap Motion Controller [24]. Of the studies that previously examined the SARA through VC [9–11] there were several limitations. First, all studies that utilized VC were reliant upon a professional rater to assess the SARA score, which significantly reduces the scalability and accessibility as professionals typically have long waiting times and are an expensive resource. Second, some items from the SARA that required elements of balance were not modified through remote testing [11], introducing a safety concern. Finally, two of the studies had sample sizes of less than 20 participants [9, 11], which raises questions regarding the generalizability of these tools and the applicability of the findings to the general population. One of these [11] also exhibited a high dropout rate of 31.5% (6/19), which may further limit the representativeness of PwA.

The SARA-Le protocol does not require additional devices, or experts for administration or scoring, and can be safely administered at the participant’s home. The SARA-Le can be used either in conjunction with in-person SARA scores or as a standalone measure. In Experiment 2, we collected data from 83 CA participants, demonstrating the feasibility and scalability of SARA-Le. As the primary goals of Experiment 2 were to test feasibility and scalability, and since completing both in-person SARA and remote SARA-Le is time-consuming, the participants were administered only SARA-Le. Future research should extend Experiment 1 to a larger and more diverse CA cohort to evaluate generalizability.

While we have addressed some of the current challenges in the field, certain limitations need to be considered. One potential limitation of SARA-Le is its applicability to patients with severe motor or cognitive conditions. Motor or cognitive impairments could affect the participants’ understanding and response to the assessment procedures. Indeed, our study primarily involved participants without severe motor or cognitive impairment (MoCA > 21 and SARA < 22). It is important to note that other studies that utilized remote assessment of ataxia, such as the SARAhome [10], predominantly also included participants in the mild to moderate range of severity (SARA score < 20). Therefore, the findings of this study and others who have conducted remote evaluations should be interpreted with caution when applied to patient populations with severe motor or cognitive impairments. Future research should consider these factors and explore methods to accommodate patients with severe impairments to ensure the validity and applicability of the results to all ranges of disease severity.

One should consider unexplained noise in SARA-Le scores. In our investigation of the SARA-Le, we encountered a few factors that may introduce unexplained variability into the scores. These considerations are essential for understanding the robustness of this new online assessment tool. First, there is inter-rater variability. The SARA-Le, like its in-person counterpart, involves subjective assessments. The SARA is an inherently subjective test, lacking uniformity in both administering and scoring items [25]. Future research can investigate the inter-rater correlation between trained raters of SARA-Le and an expert neurologist clinician.

Second, the testing environment could have potential unexplained noise. Participants complete the SARA-Le remotely from their own homes. While this user-friendly approach is more convenient, it also introduces variability. The diverse testing environments—ranging from quiet bedrooms to noisy living rooms—may affect performance and contribute to score fluctuations. Third, three SARA-Le items (i.e., gait, stance, and sitting) rely on participants’ subjective evaluations of their abilities. To prioritize safety, we modified these items for online administration. However, this subjective self-assessment could potentially introduce additional variability into the scoring process. Despite potential noise, recent research [26] suggests that self-reported subjective items can effectively track disease progression in CA. Accordingly, we observed a strong correlation between self-reported scores and objective items in the SARA-Le. Fourth, the participants in Experiment 1 were limited to SCA3. Though this homogeneity allowed for a more precise evaluation of SARA-Le, future studies should include a more diverse range of disease severities and disease types. In summary, while acknowledging potential sources of unexplained noise, our current findings support the reliability and validity of the SARA-Le when compared to traditional in-person SARA assessments. Researchers and clinicians should consider these factors when interpreting scores and designing future studies.

This study confirms the feasibility, scalability, and validity of SARA-Le as a method for assessing ataxia severity remotely in PwA. Our remote VC test offers an efficient and convenient method of testing, making it accessible to a diverse population. SARA-Le addresses scalability and accessibility in-person testing challenges, permitting repeated monitoring and providing valuable insights into ataxia progression. Furthermore, the ability to monitor PwA frequently allows for more timely interventions. In an era emphasizing personalized medicine, remote testing holds promise for providing long-term monitoring in both motor and neuropsychological realms, particularly essential for rare neurodegenerative conditions. The SARA-Le is designed for both clinical and research applications to facilitate accessible and scalable assessment of ataxia severity. As we discussed, SARA-Le allows remote ataxia monitoring without requiring in-person visits, which can be particularly beneficial for longitudinal studies, clinical trials, and telemedicine applications. We hope that remote testing will be implemented in research and clinical settings, enhancing our understanding of ataxia progression and ultimately benefiting PwA worldwide.