# Extended Reality in Applied Sciences Education: A Systematic Review
## 4 Discussion
### Evaluating Short-Term Gains and Long-Term Retention: XR Technologies' Impact on Learning Outcomes
As a result, teachers unfamiliar with these technical aspects may find the development process overly complex and time-consuming, creating an additional barrier to the widespread adoption of XR-based instruction, which extends development timelines. Moreover, the insufficient sample sizes reported in many studies are often attributed to the high costs associated with XR technologies. A review of the literature indicates that studies with smaller sample sizes typically involve 15 to 40 participants [20; 25; 26; 57], primarily due to the financial constraints imposed by these technologies. For instance, VR and MR applications frequently require expensive head-mounted displays, which significantly limit the purchasing capacity of educational institutions and hinder the widespread adoption of these tools [13]. Furthermore, many XR applications rely on high-performance hardware and computational resources, further exacerbating financial barriers. Advanced MR devices, such as the HoloLens 2, represent a substantial investment, making large-scale implementation impractical in many educational and research settings. As a result, many studies are constrained to small, convenience-based samples, which in turn limits the generalizability of their findings [67]. Student acceptance of XR technologies varies significantly. Some students experience discomfort, such as dizziness or visual fatigue, caused by head-mounted devices, which negatively affects their learning outcomes [18; 22]. Additionally, the steep learning curve of emerging technologies can deter some students, who may find the complexity of operation or lack of interest a barrier to engagement [28; 32]. To improve student acceptance, future research should focus on developing progressive instructional models that help students gradually adapt to XR technologies. Identifying the optimal integration points between technology and learning objectives is also critical. Furthermore, incorporating student feedback to refine the teaching process and designing learning activities grounded in real-world scenarios can enhance the appeal and engagement of these technologies. Teachers' acceptance and readiness play a critical role in the effective educational application of XR technologies. Studies indicate that many K-12 teachers feel unprepared to incorporate XR into their classrooms due to unfamiliarity with the technology, a lack of relevant training and resources, and concerns over operational complexity and classroom management challenges [53]. This resistance to technology integration presents a significant barrier to the promotion of XR technologies. Future research should prioritize the development of professional development programs and continuous training to enhance teachers' familiarity with and ability to use XR technologies. Tailored instructional strategies should be designed to suit the needs of various disciplines. The limited battery life of XR devices is an underexplored yet impactful challenge. In extended classroom teaching or continuous operational environments, insufficient battery capacity can interrupt teaching processes, disrupting the continuity of the learning experience [22; 48]. This issue poses a significant limitation, particularly in high-energy-demand XR scenarios, affecting teaching schedules and student engagement. Additionally, the performance degradation of devices over frequent use and the challenges of hardware maintenance further add to the concerns of educational institutions when adopting these technologies. To answer RQ4, these challenges have led most existing studies to focus on one-time applications of XR technologies, with limited exploration of their long-term potential. Future research should propose specific strategies to overcome these challenges, such as improving the portability of devices, enhancing the design of head-mounted equipment to reduce user discomfort, and leveraging technological innovations to lower costs.