Assessment of Gait Symmetry and Gait Normality Using Inertial Sensors: In-Lab and In-Situ Evaluation - Biomedical Engineering Systems and Technologies - page 225

105

105

100

100

fitted curve
lower bound 95% CI
upper bound 95% CI
baseline trial1
baseline trial2
follow-up trial1
follow-up trial2

fitted curve
lower bound 95% CI
upper bound 95% CI
baseline trial1
baseline trial2
follow-up trial1
follow-up trial2

95

95

90 90

85 85

0 0.5 1 10 20 30 40 50

average speed (m/s) - reference data normalized step length (% of hight)

Fig. 9. Normality compared to average speed.
Variables are well correlated, Spearman's rank
correlation coefficient r=-0.79, p < 0.0001.
The solid line indicates the linear model ap-
proximation a+bx, where a=95.5 with confi-
dence interval (CI) [94.9, 96.3]; and b=-2.6
with CI [-3.3, -1.9]. The dashed and dotted
lines indicate the 95% CI of predicted obser-
vations.

Fig. 10. Normality compared to average step
length. Variables are well correlated, Spear-
man's rank correlation coefficient r=-0.76,
p < 0.0001. The solid line indicates the lin-
ear model approximation a+bx, where a=95.5
with confidence interval (CI) [94.9, 96.3]; and
b=-2.5 with CI [-3.2, -1.8]. The dashed and
dotted lines indicate the 95% CI of predicted
observations.

A) EQ-5D mobility B) EQ-5D pain/discomfort

100 100

95 95

90 90

85 85

ans 1 ans 2 ans 1 ans 2

Fig. 11. Normality compared to EQ-5D TM answers regarding (A) mobility and (B)
pain/discomfort. Mobility answers - ans 1: I have no problems in walking about; ans 2: I have
some problems in walking about. Pain/discomfort answers - ans 1: I have no pain or discomfort;
ans 2: I have moderate pain or discomfort.

tendency for better health to be accompanied by better normality index. This correla-
tion is particularly strong between normality and usual activities scores, Spearman's
r=0.75, p=0.0127. There was no correlation between the health scale in Part B of the
questionnaire and normality.
Improvement in normality was calculated as the difference between baseline and
follow-up values. Figure 13 shows how improvement in normality correlates with num-
ber of days spent at the ward after surgery. Although a Wilcoxon test indicated that
there was no statistically significant difference between groups, the Spearman's rank