Validity of DynaPort GaitMonitor for assessment of spatiotemporal parameters in amputee gait

Accelerometry can be used to objectively assess the walking ability of people with a lower-limb prosthesis inside and outside the laboratory setting. In this study, the validity of the DynaPort GaitMonitor software (McRoberts, The Hague, the Netherlands) for assessing spatiotemporal parameters of amputee gait was evaluated. Fourteen subjects with a lower-limb prosthesis walked on a straight level walkway at a self-selected walking speed over three different distances. During walking, we measured pelvis acceleration using a triaxial accelerometer (DynaPort MiniMod). Mean spatiotemporal parameters were derived from these signals using the DynaPort GaitMonitor software. Similar parameters were simultaneously determined from video. Overall, the number of steps, mean step time, step length, and walking speed were detected accurately by the GaitMonitor software. No systematic deviation was found, and the accuracy of the different parameters was within 6.5%. However, step times measured separately for both the intact and prosthetic legs differed considerably between the GaitMonitor and the video. Step time was systematically underestimated by the GaitMonitor for the intact leg and overestimated for the prosthetic leg. We concluded that the DynaPort GaitMonitor is a valid instrument for assessing mean spatiotemporal parameters in amputee gait, although systematic errors in prosthetic and intact heel strike detection prevent a reliable analysis of walking symmetry.