# Impact of Gait-Synchronized Vibrotactile Sensory Feedback on Gait in Lower Limb Amputees
## 4 Discussion  
The goal of this study was to determine the impact of a non-invasive VTFS on gait characteristics such as risk of falling, coordination, walking speed and endurance of lower limb amputees. The results indicate a significantly improved performance of the overall \begin{table}
\begin{tabular}{c c c} \hline \hline
**Subject (p#)** & **Rating 5-Point Likert Scale** & **Feedback** \\ \hline
1 & Good & Would like to continue using the system. Coverage by health insurance has been requested. \\ \hline
2 & Average & Little effect in the subject’s opinion. Currently not walking at all because of contralateral knee pain. Knee arthroplasty scheduled. Wants to test again afterward. \\ \hline
3 & Good & Complete resolution of Phantom Limb Pain and better gait stability. Subject suspects a carryover effect and does not want to continue. \\ \hline
4 & Average & Little effect in the subject’s opinion; handling the cables was inconvenient. Does not want to continue. \\ \hline
5 & Best & Complete resolution of Phantom Limb Pain and better gait stability. Would like to continue using the system. Coverage by health insurance requested. \\ \hline
6 & Good & Good but the effect was not groundbreaking. Does not want to continue. \\ \hline
7 & Best & Complete resolution of Phantom Limb Pain. Would like to continue using the system. Coverage by health insurance requested. \\ \hline
8 & Average & Liked the system, but handling the cables was inconvenient. Does not want to continue. \\ \hline
9 & Best & Complete resolution of Phantom Limb Pain. Would like to continue using the system. Coverage by health insurance requested. \\ \hline
10 & Good & Liked the system, but as subject is wearing an osseointegrated prosthesis, subject does not want any external components on the residuum. \\ \hline
11 & Average & Little effect in the subject’s opinion; handling the cables was inconvenient. Does not want to continue. \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Results of the open-directed interview with concluding evaluation of the home-use. Subjects had to rate their experience with the vibrotactile feedback system (VTFS) on a 5-Point Likert Scale (Worst, Bad, Average, Good, Best). Additionally, they had to indicate whether they would like to continue using the VTFS. cohort for the TUG (\(p\) = 0.042 *), with 73% of the subjects reducing the required time to perform the test successfully. In the subsequent analyses of the three additional gait assessments, no statistically significant differences were observed. However, the results of the FSST showed a \(p\)-value close to 0.05, indicating a potential trend toward meaningful change. Notably, 82% of the participants demonstrated a reduction in the time required to complete the FSST, and similarly, 82% exhibited an increase in walking speed in the 10 MWT. Furthermore, 64% of the subjects in the 2 MWT were able to cover a greater distance within two minutes following the intervention with the VTFS, with a smaller interquartile range (IQR) suggesting more consistent data (see Figure 5). Another potential contributing factor could be the relatively brief intervention period, which contrasts with the average time since amputation (6.91 \(\pm\) 8.35 years) observed within this cohort. The TUG and FSST reference values indicating an elevated risk of falling for unilateral lower limb amputees are 19 s for TUG, and 24 s for FSST [33]. Except for two subjects (p# 11 for TUG, p# 5 for FSST), the entire cohort exhibited no increased fall risk based on the reference values even prior to the intervention (refer to Figures 6 and 7). Consequently, our findings suggest a generally low fall risk for the study cohort despite significant limb amputations, indicating that the VTFS does not contribute to an increased risk of falling for amputees. To assess the effects of the VTFS intervention on changes in the TUG and FSST, the minimal detectable change (MDC) values from Table 1 [38; 39] were utilized for reference.