The learning experience was implemented at Tecnologico de Monterrey (hereafter referred to as Tec), a private non-profit university in Mexico that recently launched its novel educational model named Tec21 Model. It provides competency-based education (CBE) grounded on the design of learning experiences to promote the development of disciplinary and transversal skills that will allow students to face the challenges and opportunities of the 21st century [24].
The Tec21 Model relies on three main pillars. Firstly, flexible and personalized programs of study. Each program curriculum is divided into three stages: (i) Exploration, a three-term stage (1.5 years) in which students get the foundations and skills of a discipline (e.g., engineering). At the end of this stage, students are expected to choose a specific academic program (e.g., biomedical engineering); (ii) Focus, a second three-term (1.5 years) stage where students are presented with core knowledge of the chosen academic program; and (iii) Specialisation, a two-term stage (one year) in which students dive into their area of specialization (e.g., biomedical image and signal analysis). Various learning opportunities are available for the students to achieve this specialization. Among them are minor and internship programs, undergraduate research, and study abroad experiences.
Secondly, CBL is the core pedagogical approach of the Tec21 Model. Its main principle involves students working with stakeholders to define an authentic, relevant challenge related to their environment, in which they will collaborate to develop a suitable solution. In addition, other active learning strategies, such as research-based learning and problem-based learning, are also used in some courses.
Finally, the third pillar of the Tec21 Model relies on inspirational professors, defined as professors who are experts in their field and actively engaged in research and professional activities. They are responsible for identifying the challenges to be tackled by students and creating the appropriate learning environments that will trigger the development of disciplinary and transversal skills.
In particular, the reported learning experience, integrated through a CBL approach, was designed and implemented in a bioinstrumentation course that is a pivotal component of our institution’s Bachelor of Science in Biomedical Engineering program. This course, positioned in the fifth term, aligns with the “Focus” stage of the program, where the curriculum is crafted to deepen students’ core competencies in biomedical engineering.
Our CBL intervention is vital in transitioning students from foundational knowledge to more complex, application-oriented learning during this stage. By confronting and addressing an industry-relevant problem, students are encouraged to apply their accumulated knowledge and skills.
The strengths of our CBL intervention are twofold. It primarily promotes active engagement with the course material, encouraging students to move beyond passive absorption of information to active problem-solving and critical thinking. This active engagement is crucial in the “Focus” stage, as it prepares students for the subsequent “Specialisation” phase and their future professional endeavors. Moreover, the CBL approach fosters a collaborative learning environment where students work in teams to navigate and solve complex problems. This collaborative aspect enhances interpersonal and communication skills and mirrors the multidisciplinary teamwork they will likely encounter in their careers. By integrating the CBL experience, we endeavor to equip our students with the necessary skills and confidence to tackle the challenges they will face in the rapidly evolving field of biomedical engineering.
Below are further details about the course context, objectives, and structure, the proposed learning experience definition and structure, the assessment tools used to collect data about its impact, and the statistical methods used to analyze the data.
Course context, structure and format
The bioinstrumentation course is required for third-year students in the Bachelor of Science in Biomedical Engineering program. This block course runs for five weeks, 16 h per week, and includes lectures, laboratory experiments, and CBL activities. This four academic credits course is organized into four modules (Table 1). The first three modules cover fundamental concepts, circuits, and applications in bioinstrumentation and are delivered through lectures and laboratory experiments (Table 2). The fourth module entails students addressing a challenge defined by an industry partner (see subsections 2.2 and 2.3 for details). Notably, challenge-related activities are assigned 47.5% of the total course time (38/80 hours). Further details on the course’s learning contents are presented in the supplementary materials.
The CBL experience reported here was implemented in the autumn 2021 course offering. Thirty-nine students enrolled in two sections and were grouped in teams of two or three to work on assignments, laboratory experiments, and CBL-related activities. Three instructors delivered the course in team teaching, but only two were assigned to each section. In other words, one of them was assigned to both sections, whereas the other two participated in one section each.
Moreover, this course was delivered in a blended format, considering the restrictions imposed by the COVID-19 pandemic. Blended learning refers to the type of education in which students learn through different media types, using electronic, web-based, and multimedia alternatives and face-to-face traditional in-classroom options [25]. Namely, lectures and class communication with the industry partner were held online to keep minimal face-to-face interactions. In contrast, lab experiments and other hands-on activities were held in person to allow students to develop lab skills. The latter occurred in an electronics laboratory with power supplies, signal generators, and oscilloscopes. Students were also granted access to this lab outside class to complete lab experiments and hands-on activities related to the challenge. The maximum lab capacity under COVID-19 restrictions was strictly enforced by lab staff.
Industry training partner description and role
Previous research has demonstrated that involving an industry training partner in CBL experiences increases their complexity and uncertainty levels. Hence, student skills development is consistently higher than traditional teaching methods [26]. Accordingly, a partnership with Compañía Mexicana de Radiología (CMR) was established to implement this CBL experience. CMR is a Mexican company established in 1973 devoted to the medical imaging industry, manufacturing radiography and fluoroscopy systems, X-ray generators, digital X-ray systems, PACS, RIS, and molecular imaging systems. It also has a partner company, Electrónica y Medicina, S.A. (EYMSA), that distributes, installs, and provides maintenance to medical equipment for several medical specialties, including radiotherapy.
CMR’s role in this CBL experience included: (i) defining a bioinstrumentation design challenge relevant to their business and the wider community and presenting it to the class (week 1); (ii) giving students midterm feedback on their progress (week 3), and; (iii) assessing their proposed solutions at the end of the term (week 5). Two R&D engineers from CMR and two field engineers from EYMSA participated in this experience.
Challenge definition and structure
Radiotherapy is a procedure for cancer treatment using ionizing radiation to destroy malignant cells. However, irradiating tumors affected by respiratory motion (e.g., lung, breast, and liver tumors) poses a risk, as radiation might unintentionally reach healthy tissues during the procedure. Respiratory-gated radiotherapy incorporates external devices to identify the phase of the breathing cycle (e.g., inspiration and expiration) and trigger radiation beams at specific times when the tumor site is predicted to be static, thus minimizing the above risk [27]. In addition, radiotherapy has also been proposed as a noninvasive technique for cardiac ablation, a procedure that scars heart tissue to block abnormal electrical signals [28]. Similarly, cardiac-gated radiotherapy ablation aims to synchronize radiation delivery with cardiac motion to increase accuracy.
In this context, students were challenged to design, prototype, and test a respiratory or cardiac gating device, which involved designing an instrumentation system to monitor the respiratory and cardiac cycle. More specifically, they were challenged to develop a bioinstrumentation system capable of sensing a signal derived from either the respiratory or cardiac cycle, implement the corresponding signal conditioning stages, analog to digital conversion, and signal processing to synchronize the physiological cycles with the radiotherapy beam. Accordingly, the challenge module was conceptually structured in three stages, each entailing some tasks:
Design
(a) identifying potential biosignals of interest for respiratory and cardiac gating and their characteristics (e.g., amplitude and bandwidth); (b) identifying the appropriate transducers to measure those signals and their principle of operation; (c) identifying user needs and requirements; (d) defining target specifications; (e) describing the gating device’s initial concept using sketches and low-fidelity prototypes, and; (f) describing its system-level architecture using a block diagram.
Prototyping
(a) designing individual stages of the device (e.g., pre-amplification, filtering, and amplification); (b) simulating each stage using relevant software (e.g., Proteus); (c) implementing the electronic circuits and testing them individually and interconnected (verification).
Testing
Conducting laboratory experiments to test the device’s functionality on healthy subjects.
Students were given a choice to work on respiratory or cardiac gating. Moreover, identifying specific breathing and cardiac cycle phases was not required but strongly encouraged. Therefore, the course involved the attainment of specific learning outcomes for competencies development as follows:
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SIIT0102 – Demonstrates the functioning of engineering systems and devices: Demonstrates the functioning of engineering systems and devices in real environments with typical and atypical functioning conditions throughout theoretical and empirical evidence obtained from diverse research and computational methodologies.
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SBI0201 – Measurement of medical-biological systems: Uses measurement tools in medical-biological systems for diagnostic, follow up and treatment of disease, using appropriate metrology and lab practices in the healthcare context. Performs measurements in real and controlled environments.
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SBI0402 – Integration of frontier knowledge in biomedical devices: Develops biomedical devices for the prevention, monitoring, treatment, or rehabilitation of disease, integrating frontier knowledge in engineering and medicine.
During the development of their solutions, students received continuous feedback from the course instructors. Additionally, there was an intermediate feedback session where they presented their progress to the training partner. Since the challenge involved technological development, the intellectual property of the proposals belonged to the students; however, in the case of further development of a prototype, the training partner and the university would establish a collaboration agreement. It was expected that the students would spend 38 h developing their prototypes. Furthermore, in agreement with the elements under the CBL framework presented in Sect. 1.1, the big idea (i) corresponds to the necessity of a respiratory/cardiac gating device for radiotherapy, the essential question (ii) refers to how do I measure the respiratory/cardiac cycle? Then the challenge (iii) is to design and develop a respiratory/cardiac gating device for radiotherapy/cardiac ablation. Then the solution development (iv) carried out by the students’ designs and prototypes, and the assessment (v) performed by professors and industry partners in the final presentations. Finally, the results are published (vi) in the document presented here.
Challenge assessment
The challenge’s assessment included three formative and two summative assessments (Table 3). Formative assessments were written reports covering different tasks from the Design and Prototyping stages of the challenge. Summative assessments included a video presentation of the device with a demonstration of its functionality, a final report capturing elements from the formative assessment, and further tasks from the Prototyping and Testing stages.
Lecturers graded and provided feedback on the formative assessments. In addition, the CMR/EYMSA team provided midterm feedback on students’ progress based on reports 1 and 2 (week 3). Finally, the video presentation was graded by the lecturers and the CMR/EYMSA team, whereas the final report was graded by the lecturers only. Notably, challenge-related assessments accounted for 48% of the final course grades.
Students’ assessment of their learning experience
Quantitative and qualitative data on the student learning experience were collected at the end of the course. These data were collected using the Student’s Opinion Survey, an anonymous internal survey with six closed-ended items and one open-ended question. Closed-ended items use a 10-point rating scale, with 10 representing the highest value (e.g., the highest level of agreement). The open-ended question allows students to comment on their learning experiences in the course. Here, only three closed-ended items are presented, as these are the most relevant to challenge-based and blended learning (Table 4). Furthermore, although this survey inquires about the course as a whole, the number of hours and the weight assigned to challenge-related activities makes it reasonable to attribute a strong influence of the CBL experience on student responses.
