Design and Validation of a Rehabilitation Robotic Exoskeleton for Tremor Assessment and Suppression

Abstract

Exoskeletons are mechatronic systems worn by a person in such a way that the physical interface permits a direct transfer of mechanical power and exchange of information. Upper limb robotic exoskeletons may be helpful for people with disabilities and/or limb weakness or injury. Tremor is the most common movement disorder in neurological practice. In addition to medication, rehabilitation programs, and deep brain stimulation, biomechanical loading has appeared as a potential tremor suppression alternative. This paper introduces the robotic exoskeleton called WOTAS (wearable orthosis for tremor assessment and suppression) that provides a means of testing and validating nongrounded control strategies for orthotic tremor suppression. This paper describes in detail the general concept for WOTAS, outlining the special features of the design and selection of system components. Two control strategies developed for tremor suppression with exoskeletons are described. These two strategies are based on biomechanical loading and notch filtering the tremor through the application of internal forces. Results from experiments using these two strategies on patients with tremor are summarized. Finally, results from clinical trials are presented, which indicate the feasibility of ambulatory mechanical suppression of tremor.

Sensory electrical stimulation for suppression of postural tremor in patients with essential tremor

“…First, mechanical systems were tested on body limbs to add mechanical resistance, such as inertial load [7][8], viscous load [9], and both inertial and viscous load [10], which reduced tremor by 40-80% [7][8][9][10]. However, mechanical systems are not entirely prepared to be used in daily life, because they are bulky, with burdensome weight, and not aesthetic.…”

Surface Electromyography: Its Role and Potential in the Development of Exoskeleton (Review)

“…The term "exoskeleton" refers to any electromechanical system that can be worn by a person to replicate the anatomical configuration of the corresponding parts of the body, in order to enhance the power of muscles by a direct transfer of mechanical energy from the device to the human [1][2][3]. The history of creation of external auxiliary equipment dates back to the 19 th century, when a Russian inventor Yagn developed the "elastiped" -a device for making walking, running and jumping easier [4].…”

Closed-Loop Modulation of a Notch-Filter Stimulation Strategy for Tremor Management with a Neuroprosthesis

“…The EMD was set to 20 ms (according to the results presented below); the antagonist pair was co-contracted for a time period equivalent to 30 • . Tremor attenuation was computed as the ratio of the integral of the power spectral density (PSD) of the tremor in the second sub-period of the trial to the same variable calculated in the first sub-period (R att ) [13,9], and reported as percentage. The pooled values of R att for the ST and NO trials were compared using a Mann-Whitney test, to assess whether the control strategy attained a significant tremor attenuation.…”