MR Compatible device for Active and Passive Foot Movements

Abstract

The present paper presents a new MR compatible robotic device able to induce foot dorsiflexion and plantarflexion movements (‘passive’ patient mode), or to set and control for a series of parameters (force, amplitude) when the same movements are performed by the subject (‘active’ patient mode). Recent studies have demonstrated that the foot dorsiflexion is a critical component of the gait cycle; thus, ankle dorsiflexion/plantarflexion has been proposed as part of locomotor rehabilitation protocols, as well as a functional magnetic resonance imaging (fMRI) paradigm for defining brain activity relevant to gait. The principal aim of this work was to develop a robotic device to be used during fMRI testing, in preand post-locomotor therapy evaluations of cerebral activity. The same device can furthermore be used in the rehabilitation of neurological paretic patients, who need to practise foot movements and/or to relearn locomotor schemas. Design criteria and implementation are described, as well as the final prototype. Great concern was given to choice of materials (for MR compatibility) and to anthropometric dimensions (for patient adapting). Furthermore pneumatic circuit and control software are illustrated. Finally preliminary results obtained from a fMRI exam on a healthy subject are pointed up.