Biomedical Engineering Reference
In-Depth Information
Tabl e 2
Upright standing
position - Results
MS subjects Healthy subjects
ML AP TD EA ML AP TD EA
6,7 11,1 145,0 5,5 2,0 3,3 85,3 0,9
Values are the mean of 3 trials for 29 MS subjects and 28
healthy subjects in millimetres
ML
Medio-lateral COP displacement,
AP
Anterior-
posterior COP displacement,
TD
Total COP displace-
ment,
EA
Ellipse area (mm2)
3.6
Berg Balance Scale
Fourteen of 28 MS subjects scored
51 points in BBS (maximum 56), with higher
scores indicating better performance. However the average BBS score in MS group
is approximately nine points less than the average score in healthy group. Ten MS
subjects scored
44, below the score (45) from which increases the risk of falls
and corresponds to 34.48% of total group. Nine healthy subjects scored 55 points,
remaining subjects reached the maximum score.
<
3.7
Upright Standing Position
Results for upright standing position are shown in Table
2
. In MS group, medio-
lateral and anterior-posterior data demonstrate a substantially displacement than
control group. A similar behavior is observed in total displacement and ellipse area
values. For each trial, an ellipse area is calculated. All the centre of pressure points
within 1 standard deviation is represented in this ellipse, so the ellipse is a repre-
sentation of the spreading of the centre of pressure line. Lower values correspond
to stable measurements. Medio-lateral COP displacement in MS subjects is the
triple value than verified in healthy subjects. Similarly the anterior-posterior COP
displacement in MS subjects has a triple value too, compared to the other group.
Comparing the results for ellipse area, the results demonstrate that the difference
is even greater, and the result is five times higher in MS subjects. These results
identified impairments in balance and greater postural instability in MS group.
To verify the behavior of the upright standing position stability parameters in
individuals with little impairment, we constitute another MS group, with 12 subjects
who have BBS score
52 points. Table
3
shows the results of this new group.
Unlike what happened with the initial group of MS, when compared healthy
subjects with this restricted group of 12 MS subjects, there are no statistical
differences between BBS averages scores. However, the upright standing position
stability parameters of this new MS group continue to demonstrate a substantially
displacement than control group. The value for ellipse area is four times higher than
verified in healthy subjects. As expected we found that disease duration positively
correlated with age and impairments. There was a moderately negative correlation
