Robot-assisted upper extremity rehabilitation for cervical spinal cord injuries: a systematic scoping review

<p><b>Purpose:</b> To provide an overview of the feasibility and outcomes of robotic-assisted upper extremity training for individuals with cervical spinal cord injury (SCI), and to identify gaps in current research and articulate future research directions.</p> <p><b>Materials and methods:</b> A systematic search was conducted using Medline, Embase, PsycINFO, CCTR, CDSR, CINAHL and PubMed on June 7, 2017. Search terms included 3 themes: (1) robotics; (2) SCI; (3) upper extremity. Studies using robots for upper extremity rehabilitation among individuals with cervical SCI were included. Identified articles were independently reviewed by two researchers and compared to pre-specified criteria. Disagreements regarding article inclusion were resolved through discussion. The modified Downs and Black checklist was used to assess article quality. Participant characteristics, study and intervention details, training outcomes, robot features, study limitations and recommendations for future studies were abstracted from included articles.</p> <p><b>Results:</b> Twelve articles (one randomized clinical trial, six case series, five case studies) met the inclusion criteria. Five robots were exoskeletons and three were end-effectors. Sample sizes ranged from 1 to 17 subjects. Articles had variable quality, with quality scores ranging from 8 to 20. Studies had a low internal validity primarily from lack of blinding or a control group. Individuals with mild-moderate impairments showed the greatest improvements on body structure/function and performance-level measures. This review is limited by the small number of articles, low-sample sizes and the diversity of devices and their associated training protocols, and outcome measures.</p> <p><b>Conclusions:</b> Preliminary evidence suggests robot-assisted interventions are safe, feasible and can reduce active assistance provided by therapists.Implications for rehabilitation</p><p>Robot-assisted upper extremity training for individuals with cervical spinal cord injury is safe, feasible and can reduce hands-on assistance provided by therapists.</p><p>Future research in robotics rehabilitation with individuals with spinal cord injury is needed to determine the optimal device and training protocol as well as effectiveness.</p><p></p> <p>Robot-assisted upper extremity training for individuals with cervical spinal cord injury is safe, feasible and can reduce hands-on assistance provided by therapists.</p> <p>Future research in robotics rehabilitation with individuals with spinal cord injury is needed to determine the optimal device and training protocol as well as effectiveness.</p

Exposure to tied-belt walking, without perturbation, augments split-belt learning on Day 2 in children <4 y of age.

<p><b>A.</b> Time courses of walking symmetry in children <4 y of age, abrupt perturbations only: Ten-step averages are shown for the young children in Experiment 1, Day 1 (i.e., those experiencing an abrupt perturbation 1^st; red), Day 2 (i.e., those experiencing an abrupt perturbation 2^nd; green), and the child controls in Experiment 2, Day 2 (blue). The convention of the graph is identical to that of <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093349#pone-0093349-g003" target="_blank">Figure 3</a>. DS – double support; COs – centre of oscillation; SL – step length. <b>B.</b> Comparison of Day 2 control data to Experiment 1, Day 1 and Day 2 data: Symbols represent forty-step averages for the same data as shown in A, for the four key time periods: baseline (BL), initial split (SPLIT), final split (FINAL), and post-split aftereffect (AE). Significant differences (asterisk) were found in the SL aftereffect between Day 2 controls and Day 1 of Experiment 1. (Comparisons within groups are not shown.)</p

Size of aftereffect was age-dependent.

<p>Bars represent mean (+1 SD) aftereffect across children. In Experiment 1, younger children showed differences between Day 1 and Day 2, whereas older children did not (compare black and gray bars; pooled across perturbation type). Child controls of Experiment 2 (CTRLS; all <4.0 y old) walked in the tied-belt condition at two speeds on Day 1, and experienced the abrupt perturbation on Day 2. Day 2 aftereffects for CTRLS (white bars) were comparable to Day 2 aftereffects for the younger children from Experiment 1 who experienced perturbations on both days, and were significantly greater than Day 1 aftereffects for these same children for SL and COs symmetry (asterisks). DS – double support; SL – step length; COs – centre of oscillation.</p

Experimental protocol and design.

<p><b>A.</b> Top graph: Schematic of split-belt testing paradigm. During a single testing session, subjects experienced tied-belt walking for 3–6 minutes (Baseline), followed by 12–15 min period of split-belt walking (Split), and a final period of tied-belt walking (Post-split). Durations of periods were determined a priori (see text). Post-split duration ranged from 3–6 minutes for children, but was extended to 21 minutes for adult subjects. The hatched bars indicate the time points of the steps used for calculation of aftereffect. Bottom graph: Two methods of introducing the 2∶1 belt speed differential: abruptly changing the fast belt, or gradually increasing the fast belt speed in increments of 0.045 m/s over the first ¾ of the split-belt period, then maintaining the 2∶1 ratio for the final ¼ of the split-belt period. <b>B.</b> Subject allocation to the two sequences (abrupt or gradual) of testing in Experiment 1. The leg on the fast belt was switched between Day 1 and Day 2. C. Child control subjects (Experiment 2) were exposed to tied-belt walking at two speeds on Day 1, and to split-belt walking (abrupt perturbation) on Day 2.</p

Experiment 1: Children, but not adults, may show greater learning on Day 2.

<p>Mean aftereffects for the two exposure sequences: abrupt 1^st, gradual 2^nd (A1G2, circles joined by solid line), and gradual 1^st, abrupt 2^nd (G1A2, squares joined by dashed line) are shown superimposed on the overall mean (bar graph) collapsed across the perturbation type. DS – double support; SL – step length; COs – centre of oscillation. Children showed a significantly larger aftereffect of COs on Day 2 (asterisk), whereas there were no statistical differences between Day 1 and Day 2 for adults. Error bars: 1 SD.</p

Day 1, Experiment 1: Initial error, but not aftereffect, is affected by method of introduction of perturbation.

<p>Top panels: Time courses of double-support time (DS), centre of oscillation (COs) and step length (SL) symmetries (means across subjects, binned), normalized to baseline, for children (<b>A</b>) and adults (<b>B</b>) for Day 1, Experiment 1. During the split period, the speed differential was introduced gradually (black traces) or abruptly (gray traces). Dashed vertical lines separate the baseline, split-belt and post-split periods of walking. Bins: 10 steps for children, 3 steps for adults; Error bars: 1 SD. Bottom panels: Across subject averages (1 SD error bars) for the four key time periods of baseline (BL), initial split (INITIAL), final split (FINAL), and post-split aftereffect (AE). Each time period is an average of 40 steps for children (<b>C</b>) or 10 steps for adults (<b>D</b>). <i>Within</i> perturbation type, only key statistical comparisons were considered: BL vs. INITIAL, FINAL, and AE; and INITIAL vs. FINAL. Black asterisks indicate statistically significant differences for gradual perturbation, gray for abrupt. Comparisons <i>between</i> abrupt and gradual groups were only significant for INITIAL (not shown).</p