Journal of Rehabilitation Medicine 51-10 | Page 11

Robotic locomotor training in rehabilitation
cols encompassing a wide range of training sessions,
found a similar weighted mean gait velocity of 0.25
m/s (5). The review by Miller et al. (9) suggests that
these gait velocities are encouraging for independent
ambulation in home and community environments.
However, currently, it is only the ReWalk exoskeleton
that is designed for use in settings outside of rehabilita-
tion facilities. Other authors report that these velocities
are not considered sufficient for community ambula-
tion. Forrest et al. (29) found a threshold of 0.44 m/s
for limited community ambulation after incomplete
SCI, Yang et al. (17) suggested that a gait velocity of
0.40 m/s enables an individual to participate in com-
munity living, while Andrews et al. (29) determined
the mean velocity necessary to cross an intersection
at traffic signals to be 0.49 m/s. Potentially, such dif-
ferences in gait velocities exist between studies due
to the variability in population, training methods and
the outcome measures used for assessing walking
performance. This inter-study variability is highlighted
in the moderate-to-high heterogeneity scores of 27%
and 60%, respectively, for the 6MWT and 10MWT
meta-analyses performed in this review (Figs 2 and 3).
Cardiovascular demand
As a result of the unstable autonomic control after a
SCI, these individuals have an increased risk of develo-
ping heart disease and stroke, with cardiovascular and
respiratory dysfunctions being among the leading cau-
ses of death for people with SCI (30). This increased
mortality risk means that early recognition and accurate
management of cardiovascular dysfunctions are crucial
to reducing their secondary risk profile (23, 36, 38).In
this review, studies considering cardiovascular chan-
ges in HR and BP indicated no significant changes in
HR with RLT interventions and reported variable BP
changes within and post RLT. Two studies reported a
significant increase in BP post-RLT (7, 24), while the
other 2 studies showed no changes across the interven-
tion (13, 20). It is important to note that the studies
that reported on these cardiovascular outcomes were
all highly variable in terms of the level and severity
of injury across participants. The higher the level of
the SCI, the greater the degree of sympathetic nervous
system dysfunction and quadriplegia results in lower
maximal HRs compared with high and low paraplegia
(33). Thus, rehabilitation interventions should consider
these factors when assessing changes in cardiovascular
function between individuals with SCI.
HR was highest during walking compared with
sitting or standing in the devices (6, 13, 20, 24), and
RLT sessions resulted in light-to-moderate levels of
exercise intensity (6, 7, 13, 14, 20, 24). Evans et al.
(14) suggested that this moderate intensity exercise is in
accordance with the American of College of Sport Medi-
731
cine guidelines for health-promoting activity levels,
according to the percentage of predicted peak oxygen
uptake (%VO 2peak ) and metabolic equivalents (METs)
expended. These results align with previous findings of
exoskeleton walking, in which studies concerned with
RPE reported exercise sessions to be consistent with
light-to-moderate exercise intensity (6, 13, 24). These
data suggest that RLT allows patients with SCI to engage
in physical activity at an intensity that provides health
benefits, yet does not result in early fatigue. RPE values
also showed that participants were able to tolerate longer
sessions and walk greater distances during each session
with lower reported RPEs over time (20).
Secondary complications
Weight-bearing activity and over-ground ambulation
have been shown to reduce many of the secondary
complications associated with SCI, by increasing body
strength and aerobic capacity, minimizing declines in
bone mineral density, improving circulation and coun-
tering the other health risks associated with prolonged
sitting (9, 15). Exercise thus acts as a health-promoting
activity following SCI (34).
Benson et al. (7) reported that the participants who
reported mild spasticity pre-session, experienced
a slight improvement post-session. The reduction
in spasticity was observed in previous case reports
evaluating the training effects of using powered
exoskeletons (18, 35). Miller et al. (9) also reported
that clinically relevant improvements were found
in self-reports for muscle spasticity in various other
RLT studies. The decrease in spasticity following
RLT might be explained by the activation of neuronal
circuits involved in walking, which is able to reduce the
under-regulated hyperactivation present in spasticity
(26). Another cause of the decreased spasticity may
be the effect of the mobilization of usually unused
muscles, which leads to muscular fatigue and muscular
reductions in co-contraction and excitibility (18, 26).
Pain reports were decreased during and after use of
the robotic exoskeletons, with one study indicating
as much as a 9% decrease in pain post-RLT (15, 24).
The decreased pain reports could be attributed to the
improved psychological benefit of walking again (26),
endogen endorphins activated by the walking exercise
(26) and reduced muscular spasticity (7, 26).
User-satisfaction
In addition to the physiological and functional bene-
fits of RLT, there are many psychological and social
benefits to standing, including improved self-image,
eye-to-eye interpersonal contact and increased inde-
pendence (2, 15, 20, 35). The majority of studies found
that the users felt safe and comfortable in the device
J Rehabil Med 51, 2019