Functional evaluation and exercise training for people living with cerebellar ataxia: the ATAEXER Trial

IMPORTANCE Cerebellar ataxia reflects a poor coordination during movements, with a progressive deterioration of gait and balance control which are reported to be the most disabling conditions affecting independence in daily activities with a considerable negative impact on quality of life. No satisfying pharmacological treatment exists, and rehabilitation programmes are necessary. OBJECTIVE To provide a hybrid training intervention model, consisting in a supervised outpatient training intervention, integrated with a home-based multicomponent exercise programme for people living with cerebellar ataxia. This study is the first to evaluate such a training model focused also on coordination and rhythm auditory stimulation in this population on clinical, functional and patient-related outcomes. DESIGN AND PARTICIPANTS Self-controlled clinical trial, in which patients with at least mild cerebellar ataxia able to walk independently were eligible, and some apparently healthy and age-matched subjects were also enrolled at baseline as controls. INTERVENTION Patients were assigned to an eight-week phase of usual care as control period (t0 – t1) and a following eight-week intervention phase (t1 – t2) with an exercise training programme consisting in four training sessions per week provided either in a supervised or non-supervised setting. MAIN OUTCOMES AND MEASURES The primary outcome was the change in the walking efficiency as cost of transport at the preferred walking speed, secondary outcomes were the ataxia severity measured by clinical scales and patient-reported, as well as muscular endurance and strength, balance control and walking ability. RESULTS 7 individuals with mild cerebellar ataxia and 9 healthy subjects completed the study. Adherence to the ATAEXER Trial was 100% and session attendance was 90%. Discriminability between ataxic and healthy subjects were a characteristic of almost all measured parameters, and the whole panel of outcome category improved with the exercise programme. The cost of transport only improved significantly after the intervention phase (0.202 at t0, 0.206 at t1 and 0.183 mL⋅(kg⋅m)-1 at t2). Walking ability during a stress-walk at fast speed and corresponding spatio-temporal parameters, as well as muscular endurance appeared most strongly associated to measures of clinical and self-reported ataxia severity (Rho = 0.77 to 0.86), while static balance control and muscular strength appeared less correlated. CONCLUSIONS AND RELEVANCE These findings provide clinicians with evidence to embrace a specific exercise training programme as a standard in clinical care pathway targeting patients with cerebellar ataxia. In addition, according to the framework to guide the selection and development of digital measures of health, a set of evaluations has been recommended looking at (i) discriminability between healthy and cerebellar ataxic individuals, (ii) association with ataxia severity and (iii) responsiveness to an exercise training programme.