Vibration stimulation seems to be an affordable easy-to-use rehabilitation tool. Focal muscle vibration (FV) has potential to reduce spasticity and enhance muscle strength and performance. Combined with robotic assisted movement therapy, the rehabilitation can benefit from improvement of more than one aspect. For example, FV could firstly decrease abnormally increased muscle tone and joint rigidity by tackling volitional control for easier robotic movement exercise. Exactly this approach is evaluated within a clinical trial presented in this paper. FV were applied to relaxed spastic wrist flexor and extensor muscles for 15min. Subsequently, the wrist was engaged in a robotic-assisted game-playing. Results from two cases who completed the trial showed short-term decrease in wrist stiffness as assessed by clinical spasticity measurement Modified Ashworth Scale (MAS). Active range of motion (AROM) and engineering joint stiffness (JS) measurements were estimated using a robotic apparatus and the results complemented previous observations. The AROM increased and JS decreased for both cases when compared at the beginning and at the end of each interventional session. These results are a part of an ongoing clinical trial but show promise for reducing repercussions of spasticity in incomplete spinal cord injury.

Vibrations can be used to convey positional or sensory information to prosthetic users. However, for the feedback to convey information consistently, daily fine-grained adjustments are required. This paper investigates whether vibration dissipation through the muscle can be tracked using EMG with the aim of providing reliable long-term sensory feedback. The results of this study showed that the magnitude of vibration artifacts can be measured using EMG and used to create a dissipation trend. This trend varies between participants but shows consistency when measured across multiple days. This novel way of measuring vibration dissipation can potentially be used as a basis of adaptive sensory control in future prosthesis studies.

Abstract-The main focus of spasticity treatment is to alleviate pain, improve function and reduce risk of additional complications. In this paper the design of a robotic system with enhanced focal vibro-tactile stimulation for the treatment of spasticity in the upper limbs is presented. Building on emerging evidence on the use of vibrations in the treatment of spasticity, we propose a new integrated approach. Our design combines the use of vibro-tactile stimulation of the high tone muscle with robotic movement assistance to augment rehabilitation outcomes in patients with spasticity in the upper limbs.