Quantifying loss of motor skills after cerebellar stroke Control behavior of cerebellar patients in a preview tracking task

Abstract
The cerebellum plays a critical role in eye-hand coordination. A lesion in the cerebellum can lead to significant motor problems in limbs, eyes and the torso. With better, more qualitative tests a medical specialist would be able to better detect motor problems and more accurately estimate the level of impairment.

This thesis project proposes a tool that provides such more detailed quantification of fine motor problems after cerebellar stroke. Using a preview tracking task and system identification techniques, control behaviour of healthy subjects has been objectively compared to that of patients suffering from cerebellar ataxia. The tests have been performed at the Dept. of Neuroscience at the Erasmus Medical Center in Rotterdam. The preview task was carefully designed to match the vulnerable subject group.

Cerebellar patients showed a significantly higher damping ratio of their neuromuscular (arm) dynamics, higher lead time constants and increased time delay compared to healthy age-matched control subjects. Also, due to affected motor skills, patients controlled with a lower gain, so less aggressively, than healthy controls. Overall, the results show that the proposed preview tracking task is a promising tool for objective quantification of loss of motor skills in cerebellar stroke patients.