Digital Theses Archive


Tesi etd-02232017-102938

Type of thesis
Biorobotic solutions to reduce the risk of falling in balance-impaired subjects
Scientific disciplinary sector
INGEGNERIA - Biorobotics
relatore Prof. MICERA, SILVESTRO
  • Nessuna parola chiave trovata
Exam session start date
This thesis was aimed at developing innovative technological solutions to reduce the risks of falling and their related injuries in balance-impaired subjects. The first step was to investigate the balance recovery response after unexpected perturbations of walking delivered by two purposely-designed robotic platforms. Consequently, a perturbation-based training and an assistive strategy were tested in individuals characterized by high risk of falling (i.e. elderly subjects, transfemoral amputees and patients with cerebellar ataxia) in order to improve their stability after sudden loss of balance and to avoid falling.<br>In Chapter 2 and 3, the lower limb intersegmental coordination of healthy young and elderly subjects was investigated during their recovery responses after slip-like perturbations of walking delivered by the SENLY platform. Results show that such coordination strategy is shared across young and elderly people, denoting that they relied on the same motor schemes during different motor tasks (i.e. steady walking and multi-directional slip-like perturbations of increasing intensity), although ageing, per se, significantly affects the corrective response of older adults. Current evidences suggested that these fast and stereotyped motor schemes result from the interaction among activities of downstream neural networks, thus providing further neurophysiological support to investigate the effects of a perturbation-based paradigm to rehabilitate walking capabilities in patients with balance disorders.<br>Accordingly, in Chapter 4, effects of repeated waist-pull perturbations on gait stability were investigated in subjects with cerebellar ataxia by using the Active-Tethered Pelvic Assist Device. Results showed that patients were able to make fast and appropriate adjustments according to the directions and the amplitudes of the perturbations, and they improved their gait baseline after a single session of the proposed perturbation-based training. The strength of the current pilot study was to introduce a novel approach to improve cerebellar ataxia from the perspective of rehabilitation of gait and balance, for which few effective therapies exist. Further studies of a larger sample size are needed to generalize and translate these evidences into a clinical environment.<br>Finally, in Chapter 5, a real-time fall detection and mitigation strategy was implemented in the control unit of the Active Pelvis Orthosis (APO), and was tested on elderly subjects and transfemoral amputees. Specifically, the lack of balance was detected in real time by a threshold-based algorithm comparing the actual kinematics of the robot with that predicted by a pool of adaptive oscillators. Then, an assistive strategy was delivered by applying torques at hip levels, providing effective countermeasures to regain stability after a slippage. Findings reported in this thesis demonstrated the potential of the light-weighted APO to assist subjects with high risks of falling during slipping events, thus potentially improving their quality of life. Future studies are required for a more focused design to further reduce the bulkiness of wearable robotic platforms and increase usability and acceptance by senior and disabled users.<br>Overall, the proposed approaches are promising to effectively reduce the risks of falling and their related injuries in subjects with balance disorders. Future works will be conducted to extend the proposed methodologies to individuals with higher risks of falling (i.e. fragile elderly subjects) and people with neurological disorders (e.g. post-stroke and Parkinson’s disease). In addition, present results will be generalized to other cause of falling (e.g. tripping and obstacle avoidance) and to the activities of daily living that involved sudden postural transitions (e.g. turning and gait initiation/termination).<br>