ROBOTIC REHABILITATION FOR THE RECOVERY OF THE INTERNAL AWARENESS OF THE BODY.

INTRODUCTION Assistive robots for the rehabilitation of the upper limb offer new opportunities in terms of treatment modalities and objective assessment. As a consequence, also the rehabilitation paradigms and goals in stroke rehabilitation are changing and should change in the future. In 2008, Wolbrecht proposed the Assist As Needed training paradigm [1] to permit the exploration of the effort-error relationship which is fundamental to stimulate motor re-learning [2]. This is valid also for Low Functioning Patients (LFPs) but, actually, it is often of little applicability. On the one hand, active robot control is impossible for LFPs. On the other hand the functional impairment may also be related to the loss of body parts awareness and, in this case, the body scheme recovery should be the first rehabilitation goal. This study aims to verify if a robotic training paradigm based on rigidly imposed movements may be an efficient tool in the recovery of the body scheme. METHODS Participants. Two case reports will be presented: 1)male, 65 years, left hemiparesis due to an ischemic stroke, 38 months from the event. 2)male, 66 years, left hemiparesis due to an hemorrhagic stroke, 56 months from the event. Materials. An end-effector robot equipped with force, kinematics and EMG acquisition systems [3]. Treatment protocol. Two movements were selected for own body exploration and for stimulating arm proprioception. Hand paths related to the Hand to Mouth (HtM) and Reaching against gravity (Rch) movements were taken from a healthy subject data base [4], scaled on the patient anthropometric measures and passed to the robot controller. During treatment, the patient was holding the robot handle that was moved at physiological velocity on the rigidly imposed paths. The treatment consisted of 40 minutes sessions (20 min. for each movement, 12 sessions, 3 per week) of robotic treatment. Measures. Patients were clinically and instrumentally evaluated at the beginning and at the end of the 4 weeks treatment. The upper-limb kinematics, dynamics and EMG activation pattern were monitored during the treatments session. The main outcome measure was the Draw a Person Test (DPT) [5]. Examples of drawings made by stroke patients are presented in figure 1. Fig1. Drawings made by stroke patients for the Drawing a Person Test RESULTS Post treatment drawings are more detailed, especially with regard to the face elements. The relationship of body parts to one another seems to improve with treatment. Instrumental data show a slight improvement in the movements related execution velocity, EMG level of activation and articular torques. DISCUSSION DPT drawings show a recovery of the internal awareness of the body. Specifically, the HtM gesture seems to enhance the recovery of the scheme of the face. HtM and Rch movements together seem to enhance the hand awareness and the recovery of the upper-limbs proportions. Instrumental data show first steps of a functional recovery process. The proposed method seems to be a suitable tool to promote the acquisition of an internal awareness of the body as first step before functional recovery. BIBLIOGRAFIA [1] Wolbrecht et al. IEEE Trans. Neural Syst. Rehabil. Engineer, 2008: 16, 286-97. [2] Morasso et al. Proceedings Inter. Conf. EMBC 2009 : pp. 2418-2421. [3] Caimmi et al. Proceedings 4th Inter. Conf. IEEE RAS & EMBS 2012: 24-27 pp.1316-1322. [4] Caimmi et al. NNR, 2008 Jan-Feb;22(1):31-9. [5] Yule et al. Br J Educ Psychol. 1967 Feb;37(1):110-1.