Table 1 Definitions of the outcome measures
From: Transfer of mode switching performance: from training to upper-limb prosthesis use
Outcome measure | Category | Representation in Fig. 4 | Calculated for | Description |
|---|---|---|---|---|
Attempts | Clinically relevant performance measures | A1–A5 | Pre- and post-test, training sessions | Successful attempts, attempts resulting in a correct switch |
Unsuccessful attempts, attempts not resulting in a switch | ||||
Number of attempts, number of attempts within a block. This measure was calculated for both successful and unsuccessful blocks | ||||
Time needed to switch | Clinically relevant performance measures | B | Pre- and post-test | The time needed to perform a correct switch. Calculated from the start of block till the moment a correct switch was detected. A shorter time needed to switch indicated better performance |
Accuracy of switching | Clinically relevant performance measures | Computed from A1–A5 | Pre- and post-test | Percentage of the attempts that resulted in a correct switch, calculated per block. The higher the accuracy of switching, the better the performance |
Amplitude | Myosignal features | C1, C2 | Training sessions | The height of the sEMG signal during a switch attempt. This measure was calculated for both sEMG signals separately and was averaged across the two (Amplitude = (C1 + C2) / 2) |
Phasing | Myosignal features | D | Training sessions | The time difference between the peak amplitudes of both sEMG signals. Since ideally the peaks occur simultaneously, a smaller Phasing represents better performance |
Width | Myosignal features | E | Training sessions | The duration between the start and end of a trigger command. The duration needed to remain below a 300 ms threshold in order for the algorithm to recognize it as a trigger. A shorter trigger duration reduces the likelihood for the algorithm to interpret the signal as an opening or closing command of the hand and thus reduces the chances of unintentional movement of the hand. Width was calculated based on the time between the myosignal that first reached the amplitude threshold (0.3) and the myosignal that last fell below this threshold. A smaller Width reflects better performance |