Physiology Research Center (PRC), Research Institute for Infectious Diseases of Digestive System and Dept. of Physiology, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, IRAN
Background: Longevity of basic medical sciences is a major concern of medical educators and physicians. It has been shown that different learning styles can affect the half-life of the material. This study aimed to evaluate the effect of partially tests during renal physiology course on "the student’s retention of renal physiology knowledge" and "knowledge loss" in pharmacy and medical students. Methods: This case-control study was performed at Jundishapur University of Medical Sciences in the academic year 2012-2013. Study populations were pharmacy students and medical students. The final renal physiology examination was on Jan of 2013 for both groups. Pharmacy students participated in three partial tests during the renal physiology course at first semester of the academic year 2012-2013 while medical students did not participate in these tests. 25 weeks after the final renal physiology examination, the both groups of students were recruited to take a retest. Retention test consisted of 17 multiple-choice questions; each question had one correct answer. Statistical paired- and independent-samples t-tests were used to analysis the results. Results: the mean scores of retention test in medical students was significantly lower than in pharmacy students (P<0.01). Pharmacy students were answered correctly 66.4±2.3% of questions, while the rate was declined to 45.15±3.25% in medical students. The rate of "knowledge loss" in medical student was (22.7±3%) significantly higher than in pharmacy students (10.86±1.5%) (P<0.01). Conclusions: The findings suggest that taking partially tests during physiology course is a highly efficient and an effective strategy to enhance "the retention of renal physiology knowledge" and delay the rate of "knowledge loss".
The basic medical sciences are included to medical curriculum approximately from mid-1800 (1). The retention or longevity of the learned basic medical sciences in preclinical period is important and a major source of concern for medical educators and physicians. They are believed that a substantial portion of these sciences are lost in clinical and final years (2). The period of time over which course participants forget half of what they have been taught called "half-life of learning"(3). Loss of some portions of the learned basic medical sciences is inevitable. Some decline in the ability to remind what was once learned is normal and happened resulted from a physiologic condition called as "forgetting" process (4) and also long-term nonuse of the learned materials accelerate the speed of knowledge loss (5). Many reports have shown that a substantial parts of the basic medical sciences taught in medical school in preclinical years are lost during clinical and final years (2). In a review study, Custer has reported that approximately two-third to three-fourth of the knowledge will be retained after one year and the rate of knowledge loss further increase up to 50% in the next year in medical education (1).
There are many factors that decrease retention of the learned basic medical sciences such as lecture-based teaching methods, lack of clinical relevance to the portions of material covered and low attention to practical application of basic science knowledge to clinical situations (6) Some suggested teaching methods to improve the half-life of learning or knowledge retention are reviewing, repetition and reinforcement, interactive learning, problem-based learning, note-taking (7), partial examinations during course (8) and collaborative-group testing (9). Therefore, the aim of the present study was to evaluate the effect of partially tests during renal physiology course on “the student´s retention of renal physiology knowledge” and “knowledge loss” in pharmacy and medical students.
This case-control study was performed at Jundishapur University of Medical Sciences in academic year 2011-2013. Study populations were pharmacy students [from the beginning of fourth semester to the end of fifth semester] and medical students [from the beginning of third semester to the end of fourth semester].The final renal physiology examination was on Jan of 2013 for both groups. Twenty-five weeks after the final renal physiology examination [Jul of 2013], the students were recruited to take a retest. There are three different methods to assess "knowledge retention" in educational contest most common methods are recognition (true-false questions) and cued recall (open-ended questions). The third method, multiple choice questions (MCQs), is a mixture of recall and recognition (10). The retention test consisted of 17 questions. Each question was followed by four statements, only one of which was correct. The questions were taken from of the course exam (8). The participation in test was voluntary and students were unaware about the time of retention test. Therefore, they had no chance to review the lesson.
Pharmacy students were participated in three partially tests during renal physiology course in the previous semester (first semester of the academic year 2012-2013) while medical students did not participate in these tests. What was the partially test? The lesson (renal physiology course) was divided by three and students took a test for each part. Each test consisted of 8 essay-questions [4 long-and 4 short-answers]. The educator and reference textbooks [Textbook of Medical Physiology; chapters 25-30; Guyton and Hall] are identical in both studied groups.
Data were analyzed using SPSS version 17 and are expressed as mean±SEM. To compare the effect of partially tests during renal physiology course on “the student's retention knowledge”, the scores of retention test analyzed with independent sample t-tests. To analysis the knowledge loss in each group, the scores of course exams in Jan 2013 were compared with their scores on 25 weeks later, retention test, using paired samples t-tests. To compare the rate of knowledge loss between groups, the scores of course exams in Jan 2013 subtracted from the scores of retention test, and the results were compared using independent samples t-tests. P
Thirty-eight percent of the studied population was men and 62% were women; mean age was 21±1 year. According to table 1, there was a significant difference between the mean scores of course exams of renal physiology on Jan 2013 and the retention test scores 25 weeks later in both pharmacy and medical students. As shown in figure 1, the mean scores of retention test in medical students was significantly lower than in pharmacy students (P<0.01). Pharmacy students were answered correctly 66.4±2.3 percent of questions, while the rate was declined to 45.15±3.25% in medical students. The "knowledge loss" in medical students (22.7±3%) was significantly higher than in pharmacy students (10.86±1.5%) (Fig. 2; P<0.01).
Table1. Comparison the Course Scores of Renal Physiology Exam and Retention Test (25 Weeks after the Course Exam).
Course Exam (%)
Retention Test (%)
β Represents Significance Difference Between Course Exam Scores Versus Retention Scores.
The findings of the present study showed 1. There was a significant difference between the mean scores of final and the retention tests in both studied groups (pharmacy and medical students), 2. The mean scores of retention test in pharmacy students were higher than in medical students and 3. The "knowledge loss" in medical students was significantly higher than in pharmacy students.
Different rates of knowledge physiology loss have been reported. D´Eon found 16.1% decline in physiology knowledge after 10-11 months to medical students (11). This rate was more in Weitman report; The “Knowledge loss” of introductory physiology course was 20% after 15 weeks on MCQs retention test (12). In agreement with these findings, the present results also showed a significant decrease in renal physiology knowledge after 25 weeks on MCQs retention test in pharmacy and medical students, 10.6 and 22.7%, respectively. This rate was lower in pharmacy students than in medical students.
A question rose from the results of the above mentioned studies? How to enhance the retention of the learned materials? In response to the question, researchers and medical educators are trying to provide new approaches of instructions to increase the knowledge retention in basic medical sciences. It is believed that if the students frequently use the learned materials there is no the retention problem (5). However, there are some factors that affect the long-term retention of knowledge such as the content and tasks to be learned, the conditions of retrieval, and the individual ability of students (13). The mentioned factors are not under control of educators or instructors.
It is suggested that instructional approaches can be impact the retention of knowledge. In terms of instructional styles, the review study of Custers provides suggestions as to how to design a course, or even an entire curriculum, in order to improve the long-term retention of knowledge (1).
Rodriguez et al have been reported taking partially exams during pharmacology course significantly increase the mean scores of retention test and their taught performance. In that study, two groups of medical students at the National University of Mexico were recruited. The first group participated in three partially test during pharmacology course while the second group did not participate. Both groups recruited to take a retention test 10-11 months later. The results showed that mean scores of retention test in the first group was significantly higher than in the second group. The scores of partially tests were 69.8% and 59.9%, respectively (5). In another study, Dobson showed that taking retrieval quizzes enhanced the retention of anatomy and physiology information. Due to the significant results, he suggested that retrieval quizzes can be an effective strategy to increase the retention of anatomy and physiology knowledge (14). According to figure 2, the mean scores of retention test in pharmacy students significantly higher than in medical students. It was 66.4% in pharmacy students whereas the rate declined to 45.15% in medical student. The reasons of this considerable difference between pharmacy and medical students would largely be related to participation in partially tests during course. Therefore, these findings together suggest that taking partially exams or quizzers during course can effectively enhance the longevity of knowledge.
According to figure 3, the “knowledge loss” of renal physiology information in medical students was two times more than in pharmacy students, 22.7 versus 10.86%. As mentioned above reports have shown different rates of the knowledge loss of the taught physiology information. The apparent difference between two groups can be related to partially test during course. Taken these results together suggest that if partially tests take place during the course, the span of knowledge retention will increase as well.The correcting papers and registering the scores after each exam was time-consuming and makes the teacher busy and was the limitation of the present study.Therefore, partially exams taking during course effectively decrease the rate of "Knowledge loss" of physiology information. In conclusion, the findings of the present study show that taking partially tests during physiology course is a highly efficient and an effective strategy for enhancing "the retention of renal physiology knowledge" and delay the rate of "knowledge loss".
The author thanks to the pharmacy and medical students who cooperated in this study. Specially thanks to Ms. Setareh Razoghi Bastak and Ms. Fatemeh Rostami Majd in organizing the retention test and to Ms. Sajedi for the scoring and correcting of the tests.
Conflict of interest: The Author declares that he has no conflicts of interest.
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