Requirements

In order to provide effective real-time visual, vibrotactile, and auditory feedback to the user, this device requires minimum delays in data acquisition, processing, and analysis. Real-time requirements differ between the two modalities.

Gait Mode

In the healthy walk, a complete gait cycle lasts approximately 1.05s, with 60.4% corresponding to the stance phase, and the remaining 39.6% to swing. In stroke survivors, this increases to approximately 1.32s, with the swing phase taking up 40.5% of the entire gait cycle [1]. Therefore, to capture the gait kinematics and provide feedback before a successive walking cycle is completed, in gait mode, delay should never exceed 2.64 ± 0.2 s, this corresponding to the gait cycle duration of average-paced hemiplegic walking.

Training Mode

In addition to auditory assistance, training mode provides visual feedback through the GUI displaying interactive games. In this context, a response time of 100 ms is perceived as instantaneous by the user [2], and it is therefore considered the real-time requirement to be met during this mode.

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References

1. J. Boudarham et al. "Variations in Kinematics during Clinical Gait Analysis in Stroke Patients," PlosUne, vol. 8, no. 6, pp. e66421, 2013
2. R. B. Miller. "Response time in man-computer conversational transactions," Proceeding AFIPS '68 (Fall, part I), pp. 267-277, 1968.