Cerebellar ataxia: quantitative assessment and cybernetic interpretation.

To assess neuromotor disorders clinicians often rely on rating scales. Unfortunately, these scales lack the sensitivity and accuracy needed to detect the small changes in motor coordination that reflect the clinical progression of the disease on the basis of which treatment programmes can be adjusted. As a contribution to this topic, the present paper proposes a straightforward kinematic and kinetic analysis of reaching movements of patients with cerebellar ataxia in conjunction with a cybernetic interpretation of the data. The aim of the approach is to capture key deficits in the underlying motor control processes. We suggest that cerebellar ataxia may be characterized by defective feedforward control.