Characterization of Upper Limb Motor Dysfunctions in Spinocerebellar Ataxia 38: Kinematic Analysis of the “Hand-to-Mouth” Task

Individuals affected by spinocerebellar ataxia 38 (SCA 38) progressively lose the ability to efficiently perform important activities of daily living involving the use of upper limbs, like personal care and feeding. However, it is important to note that data on the extent of upper limb motor dysfunction in SCAs are generally limited, and specifically, no information is currently available for SCA38-particularly in the context of performing functional tasks. To partly fill this gap, in this study we analyze the kinematic features of the Hand-to-Mouth task in 7 individuals with SCA 38 and an equally sized group matched for age and sex using an optical motion capture system, by analyzing performance, stability and smoothness parameters based on the 3D hand trajectory. The results show that, in comparison with unaffected individuals, those with SCA 38 required longer time to complete the task, especially during the going phase towards the mouth, perform more adjustment in proximity of the target and their movement results more fragmented and less smooth. Such findings provide new and relevant insights regarding the upper limb residual functions under 'real-life' conditions in SCA 38, and represent a complementary tool to the usual clinical assessment to support better monitoring the disease progression as well as the design of specific tailored therapeutic interventions.