Integrating proprioceptive assessment with proprioceptive training of stroke patients

Although proprioceptive impairment is likely to affect in a significant manner the capacity of stroke patients to recover functionality of the upper limb, clinical assessment methods in current use are rather crude, with a low level of reliability and a limited capacity to discriminate the relevant features of the deficits. In this paper we describe a new technique based on robot technology, with the goal of providing a reliable, accurate, quantitative evaluation of the position sense in peri-personal space. The proposed technique uses a bimanual, planar robot manipuladum (BdF device), whose handles are grasped by the blindfolded patient: the paretic hand is passively placed in one of 17 positions and the subject is asked to actively match the paretic hand position in space with the other hand. The position sense of the paretic arm and the corresponding deficit of space representation are characterized by means of 7 indicators: 1) positional error; 2) holding force; 3) medio/lateral shift; 4) antero/posterior shift; 5) medio/lateral skew; 6) antero/posterior skew; 7) shrink coefficient. We also show how the same experimental setup can be used for "proprioceptive training", i.e. for providing robot assistance to the paretic arm that may improve the position sense of the patient. A preliminary, feasibility test has been carried out with one patient and three controls.