A robotic exoskeleton for rehabilitation and assessment of the upper limb following incomplete spinal cord injury

Abstract

Robotic devices have been shown to be efficacious in the delivery of therapy to treat upper limb motor impairment following stroke. However, the application of this technology to other types of neurological injury has been limited to case studies. In this paper, we present a multi degree of freedom robotic exoskeleton, the MAHI Exo II, intended for rehabilitation of the upper limb following incomplete spinal cord injury (SCI). We present details about the MAHI Exo II and initial findings from a clinical evaluation of the device with eight subjects with incomplete SCI who completed a multisession training protocol. Clinical assessments show significant gains when comparing pre-and post-training performance in functional tasks. This paper explores a range of robotic measures capturing movement quality and smoothness that may be useful in tracking performance, providing as feedback to the subject, or incorporating into an adaptive training protocol. Advantages and disadvantages of the various investigated measures are discussed with regard to the type of movement segmentation that can be applied to the data collected during unassisted movements where the robot is backdriven and encoder data is recorded for post-processing.

Estimating anatomical wrist joint motion with a robotic exoskeleton

“…We selected isolated and combined wrist flexion/extension and radial/ulnar deviation movements for their unique physcial and movement properties [15]. A task similar to prior work [15] and therapeutic tasks [16] allows us to investigate the effect of anatomical and robotic joint misalignment and movement within the robot on measurements of complex joints such as the wrist.…”

“…al [11] to calculate the spectral arc length. Results were considered outliers if their value fell outside of 3 interquartile ranges past hinges [16]. All movements were analyzed together, since the goal of this analysis is not the preservation of any particular movement property dependent on movement speed or direction, but rather the comparison between anatomical and kinematic joint angle measurements.…”

A Brief Review on Robotic Exoskeletons for Upper Extremity Rehabilitation to Find the Gap between Research Porotype and Commercial Type

“…Some research groups have redesigned, remodeled and built updated version of what they had developed first. For example, ARMIN III [92] is successor of ARMIN-I [91], LIMPACT [71] successor of DAMPACE [67], MAHI Exo II [76,77] successor of MAHI Exo [84]. In later versions, they have done apparent modification to make the hardware soft, more functional and good-looking.…”

“…Also it requires equipment to reduce noise, what makes system more complex. To actuate the upper limb exoskeletons, electrical motors have been used in most devices [27,76,77,93,97,101,102] since electrical motors can produce large amount of torque and highly precise motion despite they are heavy compared to other two. The actuators to be used in exoskeleton should (a) be light (b) have high operating bandwidth (c) capable of producing precise motion and (d) deliver large amount of torque.…”

Design of a parallel-group balanced controlled trial to test the effects of assist-as-needed robotic therapy

“…Thus, a 2-sided type I error of 0.05 is used for the primary treatment comparison. Sample size is calculated for a 2-sample t test assuming a common standard deviation of 2 (calculated from the results of a previous study with 8 SCI survivors undergoing resistance training [26]), 90% power, a mean difference of 3 points in the ARAT scale (see outcome measures section below), and a loss rate of 20% 2 . A sample size of 24 admitted participants is required to detect the hypothesized 3-points difference in the two treatment groups, resulting in a final population of 10 subjects per group completing the study (20 subjects in total), given the 20% loss rate foreseen.…”