Researchers Prof Bart van de Warrenburg, Dr Roderick Maas and Kristofoor Leeuwenberg at Radboud University Medical Center in the Netherlands have recently published a paper in the journal Cerebellum on their work exploring the feasibility of the Goal Attainment Scale (GAS) in Spinocerebellar Ataxia Type-3 (SCA3), as part of the SIMPATHIC research project.
The SIMPATHIC project is a European project that aims to develop drug repurposing for rare neurological, neurometabolic and neuromuscular disorders by exploiting similarities in clinical and molecular pathology. The project includes nine conditions, of which SCA3 is one.
SCA3 is a hereditary, slowly progressive condition. The main symptom of SCA3 is cerebellar ataxia, which is usually assessed using the Scale for the Assessment and Rating of Ataxia (SARA). Whilst widespread in its use, research has shown that the SARA scale does not reflect the full extent of different individuals’ experiences of disease burden. This may be due to the variability in impact on daily life experienced by those with SCA3, and the range of additional symptoms people may have, from neuropathy to cognitive difficulties and sleep disorders. Increasing drug development in SCA3 means that trial-readiness is more important than ever before, therefore having a robust way of measuring ou
tcomes is vital.
The GAS has been proposed to capture variability between individuals in a patient-centred way. The tool involves setting personalised, symptom-related goals that are evaluated over the period in which a person is undergoing treatment for their condition to assess progress. Use of the GAS in clinical trials has been limited so far. This research explores the feasibility and content validity of the GAS through interviewing (or interviews with) 15 people with SCA3 at different stages of disease (5 with mild ataxia, 5 with moderate ataxia and 5 with severe ataxia). That is to say, how relevant the tool is for people with SCA3 and how clear the goals set are.
Participants were interviewed about their goals by a single assessor. Before the interview, participants were asked to document their symptoms and choose their top three priorities. Given that goal-setting can be more challenging in those with cognitive impairment, which many people with SCA3 experience, it is recommended that these individuals bring a caregiver to their interview to support. They were then asked to create five goals, with three being the minimum accepted. The goals were formed around a hypothetical treatment for improving SCA3
symptoms, with participants asked what they hoped to achieve after six months of treatment. Then, in reality, the level achieved of each goal would be recorded (with a score of 0 or higher indicating successful treatment). Scores would then be aggregated per participant across their goals, and the overall average would be converted into a score. The score would be compared between treatment and placebo to evaluate how effective the treatment is.
GAS goals can be grouped in two ways: by which body functions are important in the goal, or by which parts of daily activity and participation the goal is connected to. In this study, within the body functions domain, most participants’ goals were related to balance issues (30.2%), followed by coordination of limb movements (11.1%), and visual function (11.1%). Balance-related goals were ranked most important across all stages of disease. Within the activity and participation domain, most goals were related to walking/mobility-related participation (39.7%), carrying out daily routine (12.7%), and fine hand use (7.9%). In this domain, walking/mobility-related participation-related goals were ranked most important across all stages of disease.
The researchers found that symptoms and goals varied depending on the stage of the disease. People with SCA3 initially experience mild balance issues and more non-specific symptoms such as fatigue and reduced exercise tolerance. Therefore, for study participants with mild S
CA3, goals surrounding balance included only needing to take one corrective step every 20 steps to avoid losing balance, and to sleep more than 6 hours per night on average. As mobility becomes more limiting, its impact increases and starts to dominate daily concerns. For example, for study participants with severe SCA3, goals surrounding balance included walking safely for 10 meters without a walking aid or without losing balance. In more advanced stages of the disease, when independent mobility is mostly lost and more body systems are affected, non-mobility-related symptoms become more important in people’s everyday experiences, with goals such as to have part of the day without dizziness 5 to 8 times per month, or to speak clearly for 5 minutes without needing to repeat words to be well-understood.
The study showed that the GAS is feasible in SCA3 and its content is valid. However, the study did not include follow-up scoring of goals. Additionally, the small sample size of 15 people limits the extent to which the results from this study can be generalised to the wider SCA3 population. Additionally, the interviews were conducted by a single assessor, when in clinical practice individuals are more likely to be assessed by multiple clinicians. Overall, if these limitations are addressed, the GAS could be a valuable tool in SCA3 and trials of other polyglutamine ataxias.
Read the paper here.