Journal of Rehabilitation Medicine 51-1CompleteIssue | Page 61

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M. Banky et al.
the highest prevalence of lower limb spasticity and
are the most targeted muscle for BoNT-A injection
(26). Accurate spasticity assessment is an integral
part of pre- and post-BoNT-A injection protocol (14),
therefore it is imperative that the assessment process
is reliable. An accurate system that is able to provide
real-time feedback is required to improve the variabi-
lity of clinical assessment, particularly testing velocity.
Future research should focus on the validation of user-
friendly technologies that are able to provide feedback
on testing velocity in order to improve reliability. This
may provide clarity surrounding the previously identi-
fied issues regarding spasticity assessment and assist
in achieving optimal patient outcomes.
The mean peak testing velocity during the V3 move-
ment for the 5 muscle groups tested ranged from 320
to 404°/s. These velocities are far greater than the joint
angular velocity of the lower limb during functional
activities, such as walking. For example, a walking
speed of ≥ 0.80m/s is required to achieve unlimited
community ambulation (27). A recent study highligh-
ted that the mean speed of ankle dorsiflexion during
mid-swing in a cohort of healthy controls walking at a
speed of 0.80–0.99 m/s is approximately 150°/s (28).
This value is less than half of the mean testing velo-
cities for gastrocnemius (347°/s) and soleus (404°/s),
which were produced in this study. Assessors in this
study were requested to complete the V3 assessment
“as fast as possible” to align with the current MTS
testing procedure. This finding highlights the need
for further research to be conducted in the field where
testing velocity is accurately and reliably applied and
matched to functional activities, such as lower limb
angular velocity during walking.
One future research direction evolving from the
completion of this study involves investigating
whether variability of a lower limb spasticity assess-
ment is improved when the assessment is completed
at a consistent or nominated speed rather than “as
fast as possible”. Further training of the treating team
may improve the consistency with which the MTS is
applied (29). Controlling for testing velocity would
assist in identifying whether different velocities re-
sult in changes to R1, spasticity angle and X values
and which of these has the greatest relationship to
functional activities, such as walking. For example,
investigating whether a gastrocnemius spasticity as-
sessment consistently completed at 200°/s produces a
more reliable result in terms of X value, R1 and spas-
ticity angle compared with an assessment completed
“as fast as possible”. The nominated speed should
be proportional to the joint angular velocity during a
specific functional activity, such as walking, in order
to maximize the functional relevance of the bedside
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clinical assessment. It is particularly important to
ensure that the assessment speed relates to the goal
of spasticity intervention; for example, improved
walking speed, in order to ascertain a greater under-
standing between the relationship between spasticity
and functional performance to optimize treatment
decision-making and patient outcomes. However, as
the MTS is administered as a passive test, it remains
unclear how the findings of the MTS may relate to
muscles that are partially active during walking, and
how they may interact with other features of the upper
motor neurone lesion.
Study limitations
A large cohort of assessors and patients were recruited
to take part in this study, so unlike traditional reliability
studies, not all patients were tested by each assessor.
This study design was chosen due to practicality, given
the time commitment required by each patient and as-
sessor. The negative associated with this method is that
it does not allow for traditional analysis techniques,
such as correlations, to be performed. However, this
study has enabled the evaluation of a large number
of both patients and assessors and may well be more
representative of spasticity assessment in the “real
world”. This design removes the potential bias of
studies with only a single or a few assessors. Given
the level of experience in spasticity assessment, the
large cohort of assessors may, in fact, be considered a
strength of this study. In the design of this study, the V3
assessments occurred after the V1 assessments for each
muscle group. It is possible that the stretch imposed on
the muscle during the V1 assessment may have influ-
enced the V3 results. However, given that the stretch
was brief and was not sustained for sufficient time to
induce a therapeutic effect, we feel that the impact of
VI testing prior to V3 testing was minor.
There were notably fewer rehabilitation registrars or
consultants (17.6%) participating in this study compa-
red with physiotherapists (82.4%). There was, howe-
ver, no reason to expect inter-disciplinary differences
in variability. There may be differences in variability
based on level of experience, so only experienced as-
sessors who regularly complete spasticity assessment
were included. As such, the results may not necessarily
be applicable to assessors who are less experienced
or to those who primarily complete assessment of the
upper limb, such as occupational therapists.
Finally, as the MTS was the chosen outcome mea-
sure for this study, the results are specific to Lance’s
velocity dependent definition of spasticity (30, 31),
and are not applicable to other positive features of
the UMNS, such as hypertonia, co-contraction and