## 4 Discussion  
This descriptive observational study investigated the efficacy and impact of early prosthetic intervention on motor function and quality of life (QoL) in children with upper limb agenesis or amputation. Our findings based on UBET scores suggest that upper limb movements appeared faster and more fluid without the prosthesis compared to movements with the prosthesis, which were perceived as slower and more awkward. This may indicate a stronger ingrained motor pattern with the stump than with the prosthesis. Given that this was a first-time introduction to the prosthesis, adaptations to the new motor schema were likely still ongoing. Disruption of the child's established \"normal\" movement pattern could explain the observed slower and less fluid movements with the prosthesis. As a result, the child might initially perceive the prosthesis as an impediment rather than a facilitating tool. Addressing movement disruptions, improving prosthetic features, and considering the impact of motor impairments are crucial factors in enhancing the effectiveness and acceptance of prosthetic devices in children. Literature reports suggest that interventions aimed at improving movement skills in children could involve educating parents on recognizing good and poor skill performance in their children [30]. Further support for a link between movement disruptions and prosthesis use can be found in research on skilled tool use \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multicolumn{10}{c}{**Evaluation without Prosthesis—UBET Task Completion**} \\ \hline
**Time** & **Task 1** & **Task 2** & **Task 3** & **Task 4** & **Task 5** & **Task 6** & **Task 7** & **Task 8** & **Task 9** \\ \hline
6 months & 3 & 4 & 3 & 0 & 0 & 3 & 4 & 3 & 4 \\ \hline
12 months & 3 & 4 & 3 & 0 & 0 & 3 & 4 & 3 & 4 \\ \hline \hline \end{tabular}
\end{table} 
Table 13: UBET Task completion scale results without prosthesis evaluation of a single child. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{10}{c}{**Evaluation with Prosthesis—UBET Method of Use**} \\ \hline
**Time** & **Task 1** & **Task 2** & **Task 3** & **Task 4** & **Task 5** & **Task 6** & **Task 7** & **Task 8** & **Task 9** \\ \hline
6 months & E & E & E & P & P & P & E & P \\ \hline
12 months & A & E & E & A & A & A & E & A & A \\ \hline \hline \end{tabular}
\end{table} 
Table 11: UBET Method of use scale results with prosthesis evaluation of a single child. A: Active grip through the end of the device; P: Passive use of the prosthesis through the forearm or end part of the device; E: Grip through the elbow or trunk; N: No use of the affected limb. \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multicolumn{10}{c}{**Evaluation with Prosthesis—UBET Task Completion**} \\ \hline
**Time** & **Task 1** & **Task 2** & **Task 3** & **Task 4** & **Task 5** & **Task 6** & **Task 7** & **Task 8** & **Task 9** \\ \hline
6 months & 1 & 1 & 1 & 3 & 1 & 1 & 3 & 3 & 4 \\ \hline
9 months & 3 & 4 & 3 & 0 & 0 & 3 & 4 & 3 & 4 \\ \hline \hline \end{tabular}
\end{table} 
Table 12: UBET Task completion scale results with prosthesis evaluation of a single child. and prosthetic hand function. These studies have shown disruptions to typical eye-hand coordination [31]. To address these challenges and improve user experience, researchers have emphasized the importance of advancements in prosthetic features. Key areas of focus include improved glowing materials, extended battery life, enhanced hand reliability, and more natural finger movement [32]. A second peculiar finding stems from the UBET Method of use scale. During the evaluation, children exhibited a more distal execution mode (greater use of the terminal stump) for various activities without the prosthesis. However, this pattern changed with prosthesis use. Excluding the N parameter (complete non-use), children displayed a more proximal utilization of the prosthesis, likely attempting to manipulate it as if it were his/her own stump.