Effectiveness of the Hybrid Model of Case-Based Teaching in Medical Pharmacology

INTRODUCTION

There has always been a need for an alternative to the traditional didactic format of lectures in medical education.^1,2 Academic faculty have expressed doubts about the wisdom, effectiveness and educational efficacy of such a didactic format to teaching the basic medical sciences.³ Problem-based learning (PBL) is practiced in many institutions in which the knowledge is disseminated in a group-centered environment. Implementation of PBL typically as defined by Barrows et al.⁴ would be challenging to practice in all institutional systems.

It is incumbent upon medical school curricula which provide the medical student with a large body of knowledge to ensure that efficient pedagogical strategies are utilized to establish and optimize student understanding. By discussing a clinical case related to the topic taught, students evaluate their own understanding of the concept utilizing a high order of cognition. This process encourages active learning and produces a more productive outcome.^5,6

The other issue, which has been highlighted time and again, is the monotony in didactic lectures. Usually, the concentration level of the students starts diminishing approximately 10-20 minutes after the start of the lecture and improves slightly towards the end of the lecture.⁷ Providing short breaks where students can discuss amongst each other offers an excellent opportunity to break the monotony in the didactic lecture setting. The new methods of teaching such as problem-based teaching, team-based teaching and small group discussions have greatly addressed this problem. However, didactic teaching remains the primary mode of teaching in many institutions.
This study was aimed at investigating and comparing the learning outcomes of students when taught using a hybrid model of case-based teaching and the traditional didactic form of lecture delivery.

MATERIALS AND METHODS

The entire protocol was discussed and approval from the Institutional Review Board was obtained. A group of 38 student volunteers from a Medical Pharmacology course who fulfilled the essential criteria were invited to take part in the study. The students were enrolled in the Medical Pharmacology-I course, which is taught in the first year.

The students were randomly divided into two groups identified as Group A and Group B, and were informed they would have to attend two sessions one hour each for two consecutive weeks, each week constituting a different teaching methodology. Students were not informed of the topic to be taught and all the students were required to sign an informed consent form.

To start, Group A students were taught a new topic, which focused on “bacterial cell wall synthesis inhibitors.” The lecture was started with a brief introduction to the topic and was delivered in a routine didactic format. Upon completion of one major concept, a mini-case was projected with relevant questions below the case. Care was taken that 1) the case was brief (mini case) and was formulated to match the students’ level of knowledge acquired from the lecture content taught until the case projection, 2) questions were directly related to the mini-case and 3) enough time (~ 3 minutes) was provided for the students to discuss the short questions posed at the end of each case and the faculty tried their best to stay away from the discussion and allowed the students to complete the discussion part. A typical mini-case is presented in Appendix I.

The students were asked to discuss amongst themselves (in this case their immediate neighbors) for three minutes. Immediately following the discussion the faculty randomly picked individual students to explain the answer to the questions posted below the case. The student orally presented their answer while the other students in the class were allowed to comment on the question and add additional information to the answer if needed. This answering session was scheduled for approximately three minutes. The entire session lasted for 5 to 6 minutes. Two such mini-cases were incorporated within the 1-hour lecture session. The important points were summarized towards the end of the lecture session. Immediately following the completion of the lecture the students were asked to answer a 10-question USMLE type MCQ test. A time limit of 12 minutes was given to the students to complete the test. The answers along with the question paper were collected and the students were allowed to leave the lecture hall. The structure of the hybrid model used in this study is demonstrated below (Figure 1).

The next hour involved Group B, where the same topic with the same contents was taught; however, the teaching methodology utilized was a traditional didactic format with reviewing key points prior to explaining the next major concept. The lecture was completed in the same fashion as with group A by summarizing the important points covered during lecture. Immediately after the session the students were also asked to answer the same 10-question USMLE type MCQ test as completed with Group A, which had typical USMLE type questions. A time limit of 12 minutes was also given for students to complete the test.

On Week II the topic chosen was “bacterial protein synthesis inhibitors.” During this week the groups were crossed-over, where Group A was taught via the traditional didactic lecture format and Group B was taught using the hybrid model of case-based teaching (Figure 1). Immediately after the respective lecture sessions the students were asked to answer the same 10-question USMLE type MCQ test. A time limit of 12 minutes was given to the students to complete the test. The score sheets of the students were then scanned for results and analyzed.

At the end of sessions for Week II, all students participating in the study were asked to evaluate three specific criteria in the hybrid model of case based teaching on a six point Likert scale. Appendix II represents a copy of the evaluation sheet. The structure of the entire study in both Weeks I and II is summarized in Figure 2.

Means and their confidence intervals are expressed at the 95% confidence level. The standard two group T-test was used to test whether the outcomes for the two groups are significantly different. The P values reported thus reflect the probability of obtaining our data for the two groups conditional upon the null hypotheses that the two groups do not significantly differ in outcomes.

RESULTS

Data obtained from student performance on the tests following each lecture session were analyzed. In Week I Group A students were taught utilizing the hybrid model of case- based teaching, while Group B students were taught the same topic in a traditional didactic lecture format. The mean class average on the MCQ test for group A in the first week was 85.50. This was significantly higher than the mean class average of students belonging to group B where the mean class average on the MCQ test was 63.89. It should be noted that both groups were taught the same topic and were asked to answer the same MCQ test (Table 1, Figure 3).

In Week II, Groups A and B were taught in terms of the opposite teaching modality, i.e., Group A students were taught utilizing the traditional didactic lecture format while Group B students were taught according to the hybrid model of case-based teaching. In Week II the mean class average on the MCQ test for Group A was 71.79. This was significantly lower than the mean class average of students belonging to Group B where the mean class average was 84.44. Again both groups were taught the same topic and were given the identical MCQ test (Table 1, Figure 3).

We pooled the data to remove the bias of the order of treatment, topic taught and the student group composition. The Week I and Week II hybrid model of case-based teaching data was pooled and compared with the Week I and Week II traditional didactic teaching data. The average class performance was significantly higher when the topics were taught using this hybrid model of case-based teaching (85.00) than when the topics were taught using the traditional didactic format of lecture (69.73) (Table 2, Figure 4).

At the end of the sessions in Week II the students were asked to rate three specific elements related to this kind of case-based teaching by using a 6 point Likert scale. Scores were high for each of the elements rated (Table 3).

We pooled the data to remove the bias of the order of treatment, topic taught and the student group composition. The Week I and Week II hybrid model of case-based teaching data was pooled and compared with the Week I and Week II traditional didactic teaching data. The average class performance was significantly higher when the topics were taught using this hybrid model of case-based teaching (85.00) than when the topics were taught using the traditional didactic format of lecture (69.73) (Table 2, Figure 4).

At the end of the sessions in Week II the students were asked to rate three specific elements related to this kind of case-based teaching by using a 6 point Likert scale. Scores were high for each of the elements rated (Table3).

DISCUSSION

The results of this study indicate that the learning outcome is significantly enhanced with the hybrid model of case-based teaching, where students were allowed to discuss the specific points in the case that pertain directly to the topic.

The hybrid model utilized in this study showed better student performance when compared to the traditional didactic teaching method for both Group A (85.5 ± 13.56 vs 75 ± 15.73, respectively) and Group B (84.44 ± 10.97 vs. 63.89 ± 17.54, respectively). In addition, the results indicate that this optimal teaching methodology is independent of the group composition of students. The pooled data also confirms these observations of the same statements above, where there is a significantly enhanced student performance with the hybrid model of case-based teaching (85 ± 12.25 ) when compared to the traditional didactic lecture format (69.74 ± 17.32).

The results indicate that students assimilate knowledge much better when the lecture is taught with the incorporation of mini-cases, allowing for discussion and reinforcement of the key elements of the topic. While only one student was randomly picked for answering, we found that the entire class was actively involved in the discussion process. The mini-cases incorporated into lectures allowed correlation of the basic concepts to a clinical setting. Allowing students to discuss the cases with their immediate neighbors also enhanced their basic skills in communication, sharing the information with others and supporting team building skills.

The analysis of student response sheets, where students scored three criteria related to the hybrid model of case-based teaching indicates that students strongly agree that mini-cases are very useful in incorporating pharmacologic knowledge into clinical science and increases their level of confidence in approaching their first “real patient.” Student responses also show that discussing specific clinical problems in the form of mini-cases under the supervision of faculty enhanced interest among students and increased their level of confidence in gaining clinical knowledge.

It is also noted that it is possible to introduce modifications in the teaching format to allow for implementation within a traditional basic science curriculum. Such modification does not require additional resources in terms of technology or man power, which remain serious concerns when introducing new strategies into an academic environment.

Case-based large format teaching is currently utilized in the Medical Pharmacology course at this institution and we find that students prefer and enjoy the hybrid model. It allows active student participation in the learning process and moves teaching from faculty centered to being more student centered. During the discussion sessions, the instructor acts as a facilitator and supports the activity without being actively involved in the process. This method also addresses the issue of monotony in the delivery of didactic lectures, where the attention span of the student is optimal only at the beginning and end of the lecture.

We suggest that the incorporation of mini cases is a more efficient way of delivering basic science content rather than a traditional didactic format. The method is well accepted and appreciated by students. Didactic lectures remain valuable in providing students an overview of a particular topic being taught, however the format of delivery is a teacher-centered activity, which may alienate students away from the learning process. It would appear that implementation of this new mode of lecture delivery encourages students to define the learning objectives by themselves and to learn to work as a team. This mode of delivery of lectures acts as a judicious mixture of both didactic lectures and case-based problem solving learning methods.

REFERENCES

1. Sarmishtha, G., Combination of didactic lectures and case-oriented problem-solving tutorials toward better learning: perceptions of students from a conventional medical curriculum. Advances in Physiology Education. 2007; 31: 193-197.
2. Lujan, H.L., DiCarlo SE. Too much teaching, not enough learning: what is the solution? Advances in Physiology Education. 2006; 30: 17-22.
3. Schmidt, H.G., Problem Based Learning: rationale and description. Medical Education. 1983; 17: 11-16.
4. Barrows, H.S., Tamblyn, R., Problem Based Learning: an approach to Medical Education. New York: Springer-Verlag, 1985.
5. Modell, H.I., Preparing students to participate in an active learning environment. Advances in Physiology Education. 1996; 270: 69S-77S.
6. Lake, D.A., Student Performance and Perceptions of a Lecture-based Course Compared with the Same Course Utilizing Group Discussion. Physical Therapy. 2001; 81: 896-902.
7. Satheesha, B.N., The Broken Lecture: An Innovative Method Of Teaching. Advances in Physiology Education. 2006; 30: 48.

Appendix I: A 29-year-old married man is consulted by his family physician for an ulcer on the penis. On touch the ulcer is painless. History reveals that in the recent past he had unprotected sex at night clubs.

1. What is the provisional diagnosis?
2. What is the drug used to treat this condition?
3. What is the Mechanism of Action of the drug used in this case?
4. What is the drug which can prolong the duration of action of the antibiotic used in this case?

Appendix II: Survey Questions