Gait ataxia--specific cerebellar influences and their rehabilitation.

It is well known that the cerebellum is important for movement control and plays a critical role in balance and locomotion. As such, one of the most characteristic and sensitive signs of cerebellar damage is gait ataxia. However, characterizing ataxic gait is no easy task, because gait patterns are highly variable. This variability seems to result from the interaction of different factors, namely, (1) the primary motor deficits in balance control and multi-joint coordination and oculomotor dysfunction, (2) the safety strategies used, and (3) inaccurate adjustments in patients with loss of balance. In this report, we review different approaches to analyzing ataxic gait and studies to identify and quantify the different factors contributing to this movement disorder. We also discuss the influence of the cerebellum in adaptive locomotor control, the interaction between cognitive load and gait in dual-task paradigms, and the recent advances in rehabilitation of gait and posture for patients with cerebellar degeneration. In the second part, we discuss open questions concerning cerebellar mechanisms in multi-joint coordination during different walking conditions. Furthermore, we point out potential future directions in motor rehabilitation, with the objective of identifying predictors of rehabilitation outcome and the development of individualized training programs that potentially involve rehabilitation technology.