Biomedical Engineering Reference
In-Depth Information
The hand rehabilitation robot was set up for the right hand and adjusted for
each subject's hand size. Calibrations of the range of motion were carried out
and maximum voluntary contraction EMG signals and force for all subjects were
recorded before training.
6.4.1 EMG Signal Analysis
Both stroke and elderly subjects were then requested to evaluate all 3 training
modes. For each training mode, each subject was asked to perform two rounds of
five cycles of hand opening (extension) and pinch (flexion). All EMG signals and
the movement of all fingers were recorded for further analyses.
Figure 6.11(a
-f)
shows the recorded EMG signals of ED and APB muscle groups as well as the
position tracking movement of the index finger of the healthy elderly subject E4
and chronic stroke subject S4 for all 3 training modes.
For continuous passive motion, because it does not require any voluntary
effort, both groups were able to complete the full range of hand opening and hand
grasp under the assistance of the robotic system. Therefore, the EMG activation
signals were very little. For EMG-triggered motion, both subject groups were able
to trigger the movements of the robotic system. When comparing the EMG signal
strength of the ED and APB between two groups, the elderly were stronger than
the stroke group. In particularly, the stroke subject had difficulty in activating
the APB muscle (ie. distal end). For the continuous EMG-driven motion training
mode, as it required subject to continuously put effort to drive the movement,
the duration of activated EMG signals were longer in both groups. The APB
and ED EMG signals of stroke subject were not clearly distinguished from the
E
x
tensor
D
igitorum
2
0
-2
0
0.5
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3.5
4
x 10
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Abd
u
ctor Po
l
licis Br
e
vis
2
0
-2
0
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x 10
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Hand grasp
Hand
opening
Position of index finger
100
50
0
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x 10
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Time (ms)
Figure 6.11a
Continuous passive motion (CPM) for elderly subject E4. Top 2 rows are the
EMG signals for ED and APB muscle groups. The bottom row is the position feedback of
index finger movement.
