Avoiding medical skill decay: can we apply the testing effect?

Introduction: A simulator offers students an opportunity to practice skills without time restrictions. Furthermore, it can be tailored to individual student´s needs allowing then to learn at their own pace in a safe environment. However, the acquired skill will decay after a period of non-use. From cognitive psychology, research has shown that long-term knowledge retention increases more by being tested than by repeating the learning material. However, evidence for this so-called testing effect in medical skills training is lacking. In this study, we investigated whether the testing effect would improve students’ long-term retention of making a transthoracic echocardiogram (TTE). Since all skill acquisition starts with knowledge, novices would benefit from retrieving the required knowledge. We hypothesized that an interim knowledge test would improve students’ skills retention, since their performance is still not automatized, which requires students to retrieval their knowledge.
Methods: 43 medical students without echocardiography experience participated in this experiment, which was divided into three sessions. The first session, students took a baseline theory test which consisted of 14 questions on structures of the heart, three questions about manipulation of the probe and three about the functioning of the heart. Then, students watched a video which explained the basic anatomy and function of the heart, and gave an introduction on echocardiography and overview of all views required of the echo. After that, students practiced in groups of two to four people. The students practiced six views on the simulator, followed by a theory and TTE test. The practice time was equal for all students. The second session, occurred 3 weeks the training in which all students performed a theory and/or TTE test, and were assigned to one of the four groups; group 1 only knowledge test (n=9); group 2 only a practical test (n=9); group 3 both a knowledge and practical test (n=10); group 4, the control group no test in between (n=7), After eight weeks, all students took a follow-up theory and TTE test.
Results: There were no significant differences between groups for neither baseline nor end of training measurements. The interim knowledge test had an influence on the follow-up knowledge test ( F(1,31) = 1.20, p = .019) whereas the practical interim test nor taking both interim tests had a significant effect. The interim practical test had an influence on the follow-up practical test (F(1,31) = 2.99, p = .006) whereas the knowledge interim test nor taking both interim tests had a significant effect.
Discussion and Conclusion: We had hypothesized that an interim knowledge test would improve students’ retention on making an echocardiogram. However, our results demonstrated that students only benefited on the follow-up knowledge test. It seems that taking an interim practical test would be more beneficial for students in making an echo. This may perhaps be explained by the fact that making an echo is a perceptual-motor tasks in which students learn in an intuitive fashion by only practicing. In conclusion, the testing effect may avoid skill and knowledge decay. In addition, it may be concluded that the testing effect is very specific to the type of knowledge: theoretical vs practical.