Effect of arm position variation in amputated arm
The average overall classification error matrix over all
the five subjects was calculated for their amputated arms
and showed in Figure 4(a) when only using EMG signals
and in Figure 4(b) when only using ACC-MMG signals.
It can be seen from Figure 4 that using either EMG or
ACC-MMG as movement classification signal could produce
similar intra-position classification performance,
but distinct inter-position classification performance.
The average intra-position classification error across all
the five arm positions and the five subjects was around
7.3±2.3% for EMG and 9.9±2.4% for ACC-MMG, which
were no significant difference (p-value=0.11). However,
the ACC-MMG signals had much higher inter-position
classification error with an average value of 81.1±1.5%
over the arm positions and the subjects, in comparison
of the EMG signals with an average value of 29.9±3.2%;
the difference was significant (p-value