Journal of Rehabilitation Medicine 51-1CompleteIssue | Page 60

Reliability of spasticity assessment
Table III. Mean absolute differences (MAD) (95% CI) and percentage difference from mean for intra-observer and inter-observer variability
Muscle group
Testing variable
V1 gastrocnemius Start angle (°)
End angle (°)
Total ROM (°)
Peak velocity (°/sec)
V3 gastrocnemius Start angle (°)
End angle (°)
Total ROM (°)
Peak velocity (°/sec)
V1 soleus
Start angle (°)
End angle (°)
Total ROM (°)
Peak velocity (°/sec)
V3 soleus
Start angle (°)
End angle (°)
Total ROM (°)
Peak velocity (°/sec)
V1 hamstrings at Start angle (°)
40° hip flexion
End angle (°)
Total ROM (°)
Peak velocity (°/sec)
V3 hamstrings at Start angle (°)
40° hip flexion
End angle (°)
Total ROM (°)
Peak velocity (°/s)
V1 hamstrings at Start angle (°)
90° hip flexion
End angle (°)
Total ROM (°)
Peak velocity (°/s)
V3 hamstrings at Start angle (°)
90° hip flexion
End angle (°)
Total ROM (°)
Peak velocity (°/sec)
V1 quadriceps
Start angle (°)
End angle (°)
Total ROM (°)
Peak velocity (°/sec)
V3 quadriceps
Start angle (°)
Intra-observer variability Percentage difference Inter-observer variability Percentage difference
Mean value MAD (95% CI)
from mean (%)
MAD (95% CI)
from mean (%)
29.5 PF
1.6 DF
31.1
37.7
29.3 PF
6.9 DF
22.4
347.4
32.4 PF
3.8 DF
36.2
44.3
32.2 PF
5.3 DF
26.8
404.4
55.3 KF
–4.2 KE
59.5
56.2
53.7 KF
0.0 KE
53.7
319.7
92.1 KF
–20.4 KE
71.8
59.1
97.1 KF
–28.2 KE
68.9
350.9
10.0 KF
127.7 KF
117.7
72.1
9.9 KF
3.6 (2.9–4.2)
3.1 (2.5–3.8)
4.3 (3.5–5.1)
14.9 (12.5–17.8)
2.8 (2.1–3.6)
2.8 (2.2–3.5)
3.4 (2.9–4.0)
63.7 (55.6–72.7)
3.5 (2.8–4.3)
2.6 (2.2–3.0)
4.2 (3.4–5.1)
14.5 (11.7–17.7)
3.0 (2.5–3.5)
2.6 (2.2–3.1)
3.6 (3.2–4.1)
74.1 (64.6–84.4)
9.1 (7.9–10.3)
3.4 (2.7–4.3)
9.1 (8.3–10.0)
16.2 (12.8–21.1)
6.0 (5.2–6.8)
4.7 (3.8–5.9)
6.2 (5.4–7.0)
51.6 (45.2–57.8)
7.8 (6.8–8.8)
5.5 (4.8–6.2)
8.8 (7.6–10.3)
16.2 (13.6–19.0)
6.5 (5.5–7.5)
7.7 (6.9–8.7)
8.4 (7.6–9.2)
47.0 (40.7–53.2)
1.3 (1.0–1.6)
3.6 (2.9–4.3)
3.9 (3.2–4.6)
14.8 (12.5–17.2)
1.2 (0.9–1.4)
–
–
–
39.5
–
–
–
18.3
–
–
–
32.7
–
–
–
18.3
–
–
–
28.8
–
–
–
16.1
–
–
–
27.4
–
–
–
13.4
–
–
–
20.5
–
3.9 (3.1–4.9)
4.7 (4.0–5.4)
5.6 (4.8–6.3)
17.9 (15.2–21.5)
3.8 (3.2–4.5)
4.4 (3.7–5.2)
4.9 (4.1–5.7)
105.4 (92.1–119.0)
3.8 (3.0–4.6)
4.2 (3.5–4.9)
5.9 (5.1–6.7)
20.1 (16.1–24.5)
4.3 (3.6–5.0)
4.4 (3.8–5.1)
5.8 (5.0–6.5)
119.0 (104.0–134.1)
12.8 (11.2–14.9)
4.5 (3.7–5.2)
12.4 (10.9–14.0)
24.8 (19.0–30.5)
12.7 (10.8–15.1)
7.4 (5.8–9.0)
12.0 (10.5–13.6)
90.3 (77.7–105.1)
14.4 (12.4–16.6)
9.0 (8.0–10.0)
16.2 (13.8–18.8)
25.1 (20.3–30.1)
11.6 (10.0–13.3)
10.7 (9.4–12.1)
13.5 (11.9–15.3)
81.2 (72.9–90.4)
1.5 (1.2–1.9)
5.5 (4.7–6.4)
6.0 (5.2–6.9)
20.7 (17.3–24.2)
1.6 (1.3–2.0)
–
–
–
47.5
–
–
–
30.3
–
–
–
45.4
–
–
–
29.4
–
–
–
44.1
–
–
–
28.2
–
–
–
42.5
–
–
–
23.1
–
–
–
28.6
–
End angle (°) 121.9 KF 5.4 (4.4–6.4) – 9.1 (7.3–11.0) –
Total ROM (°) 112.1 5.7 (4.7–6.7) – 9.2 (7.5–11.0) –
Peak velocity (°/sec) 348.4
37.8 (32.8–43.3)
10.8
64.3 (54.1–73.8)
18.5
MAD: mean absolute difference; CI: confidence interval; V1: movement completed at a slow velocity; V3: movement completed as fast as possible; PF:
plantarflexion; DF: dorsiflexion; KF: knee flexion; KE: knee extension.
rater variability almost double that of the intra-rater
variability across the V1 and V3 trials.
Variability of total joint ROM. The quadriceps had
the greatest inter- and intra-rater variability when
analysing total joint ROM. The MAD for intra-rater
variability of joint ROM during the V3 quadriceps
assessment was 5.7° and the MAD for inter-rater varia-
bility was 9.2°. The other muscle groups demonstrated
greater inter- and intra-rater variability, with no clear
pattern regarding which muscles were assessed with
greater consistency.
DISCUSSION
57
To our knowledge this is the first study to examine the
variability of testing velocity when assessing for lower
limb spasticity in individuals following a neurological
injury. When examining the primary aim of variability
of peak testing velocity during the V3 (fast) movement,
the inter-rater variability was almost double that of the
intra-rater variability across all of the muscle groups.
In a clinical setting it is preferable that one clinician
completes all spasticity measures on a particular patient
within and between sessions; however, this is often not
feasible (20). The findings from this study may have
important implications for previously published stu-
dies examining the reliability of the MTS, which have
reported variable results in regards to the reliability of
X scores, R1 values and spasticity angles.
The magnitude of the variability in peak testing
velocity appeared to be associated with the muscle
group tested. Greater variability occurred during
the V3 movements at the ankle joint (gastrocnemius
and soleus) compared with the hamstrings, and the
lowest variability in testing velocity occurring in the
quadriceps muscle. This is potentially problematic as
the gastrocnemius and soleus muscles tend to have
J Rehabil Med 51, 2019