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ground powered lower limb exoskeletons, including
Ekso (Ekso Bionics, Richmond, CA, USA) and ReWalk
(ReWalk Robotics Inc., Marlborough, MA, USA) (5–8).
These lightweight exoskeletons are rechargeable bionic
devices with motorized joints that are worn over the lo-
wer extremities (4). They enable individuals with lower
extremity weakness to stand up and walk with a natural,
full weight-bearing, and reciprocal gait (3).
Several studies have investigated the benefits and
safety of using powered robotic exoskeletons as a
newly developed technology within SCI rehabilitation.
However, these studies consist primarily of case-series
or single-intervention trials, all with short intervention
periods (5, 9). Several systematic reviews exist on the
effectiveness of various forms of locomotor training
after SCI, including over-ground and treadmill-based
training, hybrid exoskeletons and orthotic walking aids
(5, 9, 10). These reviews consider ambulatory function
and safety as primary concerns, while user-satisfaction
and other secondary health benefits are seldom reported.
To our knowledge, no reviews have analysed cardiovas-
cular outcomes from robotic locomotor training (RLT)
interventions. Despite the depth of reviews covering
RLT, to date, only a single review by Miller et al. (9) has
performed a meta-analysis of the effect of over-ground
RLT on functional and health outcomes.
Therefore, this systematic review aims to add to the
growing field of interest and development surrounding
RLT by updating and building on the quantitative
results previously established by Miller et al. (9). In
addition, with a larger amount of literature available
on this topic, a comprehensive overview of all the
available evidence is essential to support the clinical
application of RLT for rehabilitation after SCI. Conse-
quently, this review aims to examine the effectiveness
of over-ground powered exoskeletons as a tool for
SCI rehabilitation by investigating gait parameters,
cardiovascular demands, secondary health outcomes,
including spasticity, pain and user-satisfaction.
METHODS
Search strategy
A comprehensive review of the existing literature was underta-
ken using the Preferred Reporting Items for Systematic Reviews
and Meta-Analyses (PRISMA) guidelines. The following 6
electronic databases were searched for peer-reviewed journals
published in English before 3 April 2018: PubMed, Cochrane
Library, Web of Science, Scopus, EBSCOhost (CINAHL and
Health Source Nursing/Academic) and EI Compedex Engine-
ering Village. There was no limitation on included publication
years, considering that the over-ground robotic exoskeletons did
not receive USA Food & Drug Admministration/European Com-
mision (FDA/CE) approval pre-2012. The PICOs framework
was used to refine the search to individuals with SCI involved
www.medicaljournals.se/jrm
in over-ground locomotor training using robotic exoskeleton
devices. The search terms included a combination of MeSH
keywords and free-text terms (Table SI 1 ).
Study selection
Two reviewers independently selected and assessed the studies
for inclusion eligibility. With the assistance of a third reviewer,
any disagreements were resolved by discussion and consensus.
Titles and abstracts were initially screened to exclude all review
articles, conference proceedings, commentaries, letters, book
chapters, animal or in vitro studies. Studies with fewer than 3
participants were excluded to eliminate bias inherent with case
reports. Full texts were excluded if mixed diagnoses were inclu-
ded, SCI-specific data were not reported, training was limited
to a treadmill or the protocol utilized upper body exoskeletons,
orthotic devices or hybrid (electrical stimulation) exoskeletons.
Duplicate items were excluded preceding the screening process.
Manual searches of reference lists from relevant articles were
completed. Of the 900 articles initially identified, 39 met the
selection criteria in both the title and abstract, and 22 of these
were eliminated after reading the full text. Ultimately 17 studies
were included from the online databases and an additional 10
from scanning the references of relevant articles (Fig. 1).
Data extraction
Two reviewers independently extracted the data from the
included studies using a pre-established data abstraction table
(Table I). Authors were contacted for further information if
required. Participant and experimental details were summarized
for each study, and outcome variables were tabulated provided
they were reported by a minimum of 3 of the included studies.
Non-tabulated results are shown in the Appendix SI 1 .
Outcome measures
Walking performance outcomes included: (i) the 6-min walk
test (6MWT), measures the distance and velocity walked over
a 6-min period, and serves as an indicator of submaximal
aerobic capacity; (ii) the 10-metre walk test (10MWT) measures
the velocity achieved during a 10-m walk; (iii) Timed Up and
Go (TUG) tests the time required to stand up, balance and sit
down again. Cardiovascular demand outcomes included heart
rate (HR), blood pressure (BP) and rating of perceived exertion
(RPE). RPE values were self-reported according to the Borg 6–20
scale. Secondary complications, including spasticity and pain,
were measured using subjective ratings: numeric rating scale of
0–10 for spasticity and 0–6 for pain, as well as visual analogue
scales (VAS) using a 10-cm ruler and a marker that the participant
moves to the point indicating the intensity of pain. Clinical tests
included the Modified Ashworth Scale and the Spinal Cord As-
sessment for Spastic Reflexes. User-satisfaction utilized a variety
of subjective rating questionnaires assessing the acceptability of
the exoskeleton device and quality of life (QoL) scores.
Quality criteria
The quality of evidence of the extracted data was assessed accor-
ding to the Grading of Recommendations, Assessment, Develop-
http://www.medicaljournals.se/jrm/content/?doi=10.2340/16501977-2601
1