My 16-year-old nephew was asked to give a presentation on the physiology of the eye, and sought my help the night before it was due. He had found his textbooks with all their scientific terminology to be more confusing than helpful. Since my nephew is an avid photographer, I hoped that I could use his interest in photography and understanding of how a camera works to make short work of the lesson. Likening the eye to a camera and the retina to photographic film, we drew corollaries between the two types of cameras: man-made and natural. We went on to discuss monocular and binocular vision, this time figuring out that, while both eyes can move independently, the brain works as a computer to fuse images from each eye. Soon, he surprised me with the observation that the cameras have to move in synch (conjugate eye movements) for the computer (brain) to fuse the images. We ended the session by discussing not only diplopia, but blindness and stereoscopic vision as well. I was impressed that he had grasped the concepts with such facility. He went on to ace the assignment.
I would have forgotten about that experience with my nephew, were it not for the fact that my third-year medical students, during a bedside tutorial, also had difficulty grasping the concept of monocular blindness in the patient we were discussing. I tried the same simplified explanation with them and was heartened by the alacrity with which they understood the lesson.
Later, when I was asked to give a lecture on neurologic localization, I again decided to present the material in simple, familiar terms. I highlighted the brain as a computer, and the spinal cord as the conduit, or bunch of wires (nerves), carrying information to computer peripherals (limbs and sense organs). The students were soon able to understand how cutting a single wire (nerve) would only disable one part of the system, whereas damaging the conduit (spinal cord) would cause more widespread effects.
I enhanced my simplified approach to explaining neurologic localization with several video vignettes to further illustrate the concept. This combination proved to be a successful way to reach the students, as they demonstrated by acing the quiz I gave them at the end of the lecture. In their feedback assessments, the students responded very favorably and praised the fact that the lecture dealt with the familiar subject matter of computers.
I have since tried, when possible, to apply this philosophy of using familiar subjects to facilitate understanding and sustain interest, both in small- group sessions as well as in lectures. I have yet to be disappointed with the results.
Erle C. H. Lim, MD