Journal of Rehabilitation Medicine 51-1CompleteIssue | Page 58

Reliability of spasticity assessment
strength, the weight or size of the patient limb being
tested and the properties of the individual muscle. Ve-
locity is a key component of the definition of spasticity,
and the recommended instruction is to move the limb “as
fast as possible” during the V3 (fast) component of the
assessment. There is no defined or recommended testing
speed when testing the major lower-limb muscles, and
the most appropriate testing speed during a V3 move-
ment is unknown. The variability surrounding testing
speed is also currently unknown, so it seems reasonable
to suggest that further research needs to be conducted
to investigate the variability of testing velocity using
the MTS. The primary aim of this study was therefore
to establish the inter- and intra-rater variability of the
V3 peak testing velocity when assessing for lower limb
spasticity using the MTS in adults who have an acquired
brain injury. The secondary aim was to establish the
inter- and intra-rater variability of the joint start ang-
les, end angles and total range of motion (ROM) at V1
(slow) and V3, as well as the V1 peak testing velocity
when assessing for lower limb spasticity using the MTS.
METHODS
This study was approved by the Epworth HealthCare Human
Research Ethics Committee (HREC 681-15) and the University
of Sunshine Coast HREC (S/17/1011). All participants provided
written informed consent prior to assessment.
Participants
Two groups were recruited to participate in this study: (i) adults
with an acquired brain injury or neurological condition; and (ii)
clinicians experienced in the assessment of lower limb spasticity.
Group 1: Patients with a neurological condition. A convenience
sample of 35 individuals with a neurological condition was re-
cruited to participate in this study. This exceeds the sample size
used in previously published studies examining the reliability
of other components of the MTS (17, 19–22). Each participant
attended a single assessment session, lasting approximately
1.5 h. The inclusion criteria were: (i) diagnosed with a neuro-
logical condition, (ii) identified by their treating therapist or
rehabilitation consultant as having 2 confirming features of the
upper-motor neurological syndrome (radiological or clinical),
(iii) attending physiotherapy for mobility deficits related to their
neurological condition, (iv) able to have the MTS completed
on their affected lower limb, and (v) adults (> 18 years of age)
who were able to provide informed consent. The exclusion
criteria were concurrent diagnosis of a congenital neurological
or peripheral nervous system condition.
Group 2: Clinicians experienced in spasticity assessment.
Physiotherapists, rehabilitation consultants and rehabilitation
registrars were recruited as assessors from a range of healthcare
networks. The assessors were eligible for inclusion if they had
at least 3 years’ experience in neurological clinical practice and
regularly assessed and treated spasticity within their clinical
practice. Each assessor attended an assessment session lasting
4–6 h. Assessors were asked to complete the assessment protocol
on 2, 3 or 4 participants pending their availability. This figure
55
was chosen in consultation with a biostatistician and enabled a
large, representative group of assessors to be recruited. It was
planned that assessors were available to complete a minimum
of 3 patient assessments. However, the option of 2 was included
to enable the recruitment of several highly-specialised clinicians
who were unable to commit to 6 h of testing.
Data collection
The MTS involves stretching the relevant muscle through its
entire ROM at a slow velocity (V1) and then a fast velocity
(V3) (18, 23). The end angle during the V1 movement, or full
passive ROM, is referred to as R2 and the angle of muscle reac-
tion during the V3 movement is referred to as R1. The spasticity
angle refers to the difference between R2 and R1, with a larger
spasticity angle indicating a larger degree of velocity dependent
spasticity (23). A 5-point scale (see Appendix I) is used to rate
the type of muscle reaction (X value) which occurs during the
V3 movement, ranging from no resistance through to infatigua-
ble clonus. The MTS was completed on the more affected lower
limb of each participant for the gastrocnemius (supine, leg ex-
tended), soleus (supine, hip and knee flexed to 90°), hamstrings
at 40° hip flexion (supine, full knee flexion), hamstrings at 90°
hip flexion (supine, full knee flexion) and quadriceps (prone, leg
extended) using standardized testing positions (20, 23). Three
V1 and 3 V3 trials were performed for each muscle group by
3 different assessors on each participant, totalling 90 trials per
participant (i.e. 3 slow movements and 3 fast movements per
assessor for each of the 5 muscle groups tested).
Participants were asked to remain relaxed throughout the
assessment and the following instructions were provided to
the assessors:
• R2: the assessor was asked to move the joint slowly through
its full available ROM.
• R1: the assessor was asked to move the joint through its
full available ROM as quickly as possible. Assessors were
instructed to stop at the “point of muscle reaction” during V3.
Therefore, R1 reflected the angle of muscle reaction during
the V3 movement. No further guidance regarding velocity of
assessment was provided.
The assessors were blinded to each other’s assessment to
avoid adjustment of testing velocity or joint position based on
observing other assessor’s movements. The order of the 3 as-
sessors was randomized for each of the muscle groups tested
for each participant to minimise any bias caused by repeated
stretching applied by the same therapist.
For each trial, the relevant movement was recorded using
a 13-camera 3-dimensional motion analysis (3DMA) system,
Optitrack. This system uses small, light-reflective markers
which are monitored at a speed of 120 Hz to accurately record
joint movement. For each muscle group the markers were
placed on specific anatomical landmarks of the lower limb
which have been outlined in Table I. Motive Body software,
Table I. Anatomical landmarks for marker placement
Label Landmark Trials to be used for
GT
ADD
MKNE
LKNE
MMAL
LMAL
MCALC
MTH1 Greater trochanter
Proximal adductor
Medial epicondyle of knee
Lateral epicondyle of knee
Medial malleolus
Lateral malleolus
Medial calcaneus
Metatarsal head 1 Quadriceps
Hamstrings
Gastrocnemius,
Quadriceps
Gastrocnemius,
Quadriceps
Gastrocnemius,
Gastrocnemius,
soleus, hamstrings
soleus, hamstrings
soleus
soleus
J Rehabil Med 51, 2019