# Inertial Sensors-Based Assessment of Human Breathing Pattern: A Systematic Literature Review
## 3 Data Analysis, Results, and Discussion
### Is There an Ideal Number of Sensors and Configurations to Accurately Assess Adult Human BPs?  
This review provided insights into the optimal number of sensors and setup configurations for assessing BPs. Studies showed that accelerometers placed on different anatomical regions, such as the upper chest, lower chest, and abdominal wall, were effective at detecting specific BPs. Furthermore, the use of multiple sensors, including accelerometers,gyroscopes, and magnetometers, was common in the research, enhancing the robustness of data collection and analysis. These findings suggest that the choice of sensor placement and the use of multiple sensors can be tailored to specific research objectives and the desired level of accuracy.  
What Are the Main Challenges and Limitations When Using Inertial Sensors in Assessing Adult Human BPs?  
Several studies have investigated the impact of changing body positions and dynamics on data acquisition using inertial sensors, revealing the versatility of these sensors in capturing BPs across various contexts. While most research has focused on measuring BPs at rest, some have explored scenarios involving physical activity, speech, and sleep, demonstrating the potential of inertial sensors. However, these studies have also highlighted challenges related to sensor alignment and potential errors during specific activities, which researchers need to consider when designing experiments in dynamic settings. This review has also underscored several challenges and limitations associated with using inertial sensors for assessing BPs, including issues with sensor accuracy, potential errors during sensor alignment, and difficulties in identifying specific events like hypopnea. Furthermore, variations in sensor types and sampling rates observed across studies have emphasized the importance of standardizing approaches in future research. These findings emphasize the need to address these challenges and limitations to improve the reliability and accuracy of inertial sensor-based assessments of BPs.  
What Insights Have Been Gained, and What Future Directions Are Envisioned for Applying Inertial Sensors in the Assessment of Adult Human BP?  
Based on the findings of this review, several future directions can be envisioned for applying inertial sensors in the detection of adult human BPs. Researchers should continue to explore advanced sensor fusion methods and data signal analysis techniques to enhance the accuracy and reliability of BP assessments. Additionally, the development of robust classifiers tailored to specific clinical applications should be a focus of future research. Standardization of sensor placement and data collection protocols can help reduce variability and improve comparability across studies. Moreover, investigating the feasibility of the real-time monitoring of BPs using wearable inertial sensors holds promise for clinical applications and the early detection of respiratory disorders.  
However, despite the valuable insights gained from this systematic literature review, it is important to acknowledge and address several limitations inherent in the methodology and scope of the study. Because the study is a systematic literature review rather than a true systematic review, the authors chose not to assess certainty, considering one of the inclusion criteria being papers published in scientific peer-reviewed journals. Additionally, this review took a descriptive approach to provide a comprehensive overview of the literature. Due to the specific inclusion/exclusion criteria focusing on particular aspects of the research topic, the authors did not formally assess the risk of bias for included studies. While a formal analysis of result strength was not performed, all compiled information was based on the authors' six specific research questions.