Valoración de las variables

Contrary to popular belief, there is little evidence in the literature to suggest that all knowledge obtained during pre-clinical years is lost within a short period (Custers, 2010; Custers et al., 2011). In fact, it is estimated that one-third of the knowledge that has been gained but has not been used, revisited or relearned since it was first learned is likely to be forgotten during the first year, followed by 50%–60% loss within two years (Custers, 2010). The few studies that have focused on retention of knowledge past a two-year period suggest that retention declines over time, but at a decelerating pace (Custers et al., 2011; Ellis, Semb, & Cole, 1998; Rico, Galindo & Marset, 1981). A cross-sectional study by Custers et al. (2011) involves three groups of participants: medical students in their final year, medical students who recently graduated and practicing doctors who in some instances had graduated 55 years ago from the time of the study. The participants were examined for their knowledge of basic sciences involving anatomy, physiology, biochemistry and pathophysiology. The study finds a

modest decline in basic science knowledge, including anatomy, with students in medical school and recent graduates performing better than doctors who had been out of medical school for many years. The test questions in the study were mailed to participating doctors, who were advised to refrain from using books and computers, and from discussing the questions with others, when completing the test. Since it was impossible to control for cheating on such a test, one could question whether the results of the study represent an honest reflection of the participants’ knowledge in the general basic

sciences. However, the trend is in the expected direction and is therefore intuitively plausible.

To date, few studies have specifically assessed students’ knowledge of anatomy. Rizzolo et al. (2010) highlight the importance of clinical anatomy and its significance in maintaining long-term retention by redesigning a classical anatomy course at Yale University so that their new and shortened version placed a relatively large emphasis on clinical anatomy. They then compared the performance of students from both the classical and clinical courses one and a half years and three years after completing the anatomy course (i.e., before entering clerkship and after completing clerkship

respectively) using a computer-graded assessment with 49 MCQs. The results show that, compared with students who undertook the original course, those who were part of the shorter, more clinically focused anatomy course performed as well, or better, on every section of the anatomy examination. Therefore, retention was better in the clinical anatomy group. This supports the evidence that if a course is designed and structured in a way that highlights its relevance to the profession at hand, it can result in high levels of satisfaction and better learning outcomes for students.

In another retention study, Spielmann and Oliver (2005) concurrently examine medical students in the final two years of their five-year degree, as well as junior and

senior doctors (including surgical trainees), regarding their knowledge of carpal bone anatomy (eight bones of the hand). They find that junior medical students performed worse on specific knowledge-based assessments than senior clinicians, and 30% of all respondents (the majority of them senior doctors) scored 100%, with medical students displaying the poorest retention. Similar findings are made in a study that examines carpal bone anatomy among second-year (pre-clinical) and fifth-year (clinical) students in a chiropractic course (Meyer et al., 2015). These two studies have quite a few

limitations. First, the results are not surprising because one can hypothesise that senior physicians and surgeons, who have had more clinical, focused and repeated exposure and experience, are more likely to perform better on an anatomy test than medical students, who have probably not spent sufficient time learning the material. Similarly, clinical students are more likely to perform better than pre-clinical students. Therefore, exposure is a confounding variable. Further, the carpal bone test administered in this study is a crude measure of assessment. It does not provide a clear indication of

students’ anatomical knowledge because it only assesses a small region of anatomy, and it does not provide insights into the level of anatomy knowledge present during

different stages of students’ medical training (Spielmann & Oliver, 2005). In addition, the main clinical significance of the eight carpal bones lies with that of the scaphoid, which is the most commonly fractured bone in a fall or accident (Meyer et al., 2015). Coincidently, this bone was correctly identified by 92% of participants in the study, this was followed by the lunate and hamate as the most identifiable carpal bones, and the remaining five were more difficult for medical students than for the senior house officers. Another limitation of this study is that carpal bone anatomy assesses specific knowledge in students—most of which is not clinically relevant. Therefore, medical students who are faced with the challenge of memorising and assimilating large

amounts of information often remember content that has clinical significance rather than content that is purely fact-based and is probably required for specialities such as surgery and radiology.

A longitudinal study that examines retention of anatomy demonstrates that the identification of normal and abnormal radiographic anatomy, which was learned and assessed in the first two pre-clinical years, was extremely poor when medical students were assessed in the fourth year, with more than 90% failing to identify key features (Feigin et al., 2002). Similarly, recall of specific chest radiological landmarks by second-year medical students was excellent at the time and immediately after the teaching was delivered, but the knowledge dissipated two years later, as demonstrated by students’ scores, which were assessed before commencing fourth year. A revision course in the area was then delivered and, not surprisingly, the results show that knowledge that is initially learned and forgotten quickly rebounds in post-test scores following the revision course, and the scores are higher than both the pre-test scores (in fourth year) and the original scores obtained during the second year (Feigin et al., 2007). This supports the rationale that if students are prone to adopting a surface approach the first time around (particularly with specific knowledge), either because of time constraints or a lack of engagement with the material, then the knowledge acquired during that period is quickly forgotten because there has not been sufficient time for consolidation and long-term retention to occur. However, the study also reveals the significance of the testing effect in aiding retention and the importance of vertical integration in the curriculum, suggesting that knowledge that is initially learned and forgotten can be relearned with greater ease if the opportunity and the environment for refreshing the knowledge are appropriately structured—that is, relearning takes place within or alongside the clinical environment.

A similar study investigates the processes of knowledge retention and retrieval in chest radiographic anatomy (Magid et al., 2009). Students who had previously

received instruction in radiology during their second year had their pre-test and post-test anatomy scores in the fourth year compared with a group of fourth-year students from another institution. The latter students had not received a formal radiology instruction course in their second year, but they were due to complete a one-month elective in radiology during the clinical years. The students from the second institution were assessed at the beginning (pre-test scores) and end (post-test scores) of the elective course. The results reveal a statistically significant and large difference in post-test scores between students with no formal radiology teaching in the second year (i.e., students scored lower) and students enrolled in the institution that mandated the course (i.e., students scored higher) (Magid et al., 2009). The results emphasise the importance of introducing clinical concepts such as radiology teaching during the pre-clinical years. Although learning new content for the first time might be easily forgotten if the content is not revised or used consistently, the results demonstrate that revision and repetition of prior knowledge enhances the acquisition of knowledge and leads to rapid relearning (Magid et al., 2009), thereby justifying the implementation of a spiral curriculum. It also suggests that curriculum experts should not assume that casual exposure to imaging during clinical years will be sufficient in conveying radiological anatomy to students who have not been exposed to these concepts in the pre-clinical environment.

According to Magid et al. (2009), retention of knowledge for initially learned material is 33% at one week, decreasing to 14% at nine weeks. However, if students are

encouraged to revise and rehearse existing material, knowledge retention increases to 70%–83%.

Lastly, a pilot study of newly qualified doctors at the University of Aberdeen finds that only 17% had attained the anatomical knowledge required to pass a clinically relevant anatomy assessment (Waterston, Keenan, & Stewart, 2004). The assessment is based on material covered in the first-year anatomy course at the university, and the results challenge the notion that clinically relevant anatomy introduced in the pre- clinical curriculum is sufficient to provide students with the foundations for clinical practice. However, one can argue that the method of delivery during the first-year course needs to be explored further before the results can be generalised. Nonetheless, the study suggests that more vertical integration of anatomy is warranted throughout the medical curriculum to aid students and future doctors in retaining this knowledge. All of the retention studies indicate that knowledge declines over time—particularly when there is no exposure to the discipline during the clinical years. The concept of retention of anatomical knowledge will be explored in this study as it relates to pre-clinical students who are immersed in formal anatomy teaching, as well as clinical-year students whose exposure to formal teaching may be highly varied. The results of this study will provide insights into how much anatomy students learn, when and why they forget anatomy and how the curriculum can be improved to foster better learning and retention.