Interactive Large Group Lecture Demonstrations: Dramatization of Medical Neurobiology Concepts to Improve Student Perception of Understanding Fluid Mechanisms of the Central Nervous System

Abstract

With the advent of recorded lectures, face-to-face teaching in medical school large classroom settings is increasingly under pressure to incorporate engaging activities that encourage attendance and can translate to greater attainment and long-term retention for learners, especially of “Generation Z” learning styles. This places a greater onus on lecturers to convey key concepts in a manner that holds value beyond their recorded substitute. The present article details several on-stage Medical Gross Anatomy and Neurobiology demonstrations that involve the teaching of an intuitive understanding of brain fluidic mechanics, such as hematoma formation and the protective functions of an intact cerebral spinal fluid system (addressing concussion and lumbar punctures). These demonstrations can be presented relatively quickly on stage and are suitable for engaging large classroom sizes (n > 100), which can be used in conjunction with traditional lecture formats. Ideally, these in-class demonstrations, together with the continued contributions of other quantitatively assessed demonstrations from other institutions, will help to maintain a growing body of large class face-to-face teaching approaches and strategies to help influence decisions regarding what basic medical knowledge may best be taught in class live versus by recorded substitute or other non-traditional lecture methods.

Introduction

While small-group teaching is arguably a more ideal setting for many forms of medical education, large-group teaching can remain as a more efficient and less faculty resource-intensive approach if modified appropriately [1–5]. Attendance in large classrooms has become a major issue of concern nationwide, placing new emphasis on flipped classrooms or other mixed approaches [6–11]. This appears to be especially true for learners of “Generation Z” who grew up with video technology readily available through smartphones and other media [12, 13]. This cultural change has placed an ever greater onus on making classes worthwhile attending, rather than allowing learners to skip class and rely on recorded substitute (“lecture capture”; such as PanOpto, Camtasia, and any of various other forms of recording the audio or audiovisual elements of a lecture) and the potentially negative externalities related to the unintended reduction of live teacher-learner interactions in education [14, 15]. Identifying what types of learning experiences are best taught live, and that convey long-term retention, thus remains as an area of active didactic research. Our research details two sets of teaching demonstrations relating to the clinically relevant fluid mechanics of the brain (the second representing a series of demonstrations involving one to four interrelated parts). The demonstrations vary in format (e.g., short explanation of a process with images, full performance with props, active manipulation of models), and curriculum opportunities (e.g., basic science courses, physical diagnosis examination skills).

Regarding the definition of on-stage “demonstrations,” the Medbiquitous Curriculum Inventory Working Group defines demonstration as “a description, performance, or explanation of a process, illustrated by examples, observable action, specimens, etc.” [16]. All of the demonstrations of the present study were inspired by the spirit of interactive lecture demonstrations (ILDs) used in large classes of, for example, college-level chemistry and physics courses [17, 18]. Thus, for the purpose of this article, we further define teaching demonstrations (“demos”) as semi-theatrical, student-involved productions specifically designed for the lecture content with the purpose of reducing cognitive load while increasing active connection to material.

The implementation of the in-class demos described herein was initially designed to generate student interest in learning the mechanisms behind disease states germane to fluidics of the brain—namely blood and cerebral spinal fluid (CSF) systems—during live, face-to-face lectures. This includes, for example, the formation of an epidural hematoma, the mechanics of headaches resulting from a lumbar puncture (spinal tap), and understanding how potential concussions are minimized or prevented by the integrity of a closed-CSF system. All demos were taught in a large-group teaching modality, which had been assessed from 2017 through 2019 using student questionnaire data at two time points (immediately and roughly 3 years after the course) to determine parameters of effectiveness based on student feedback. A major goal of the demos was to develop innovative approaches with large-group instruction that were deemed to have significant impact in knowledge acquisition through engagement, and thus a greater likelihood of maintaining longer-term retention through pre-clinical and clinical learning environments due to attending class [19, 20].

We hypothesized that inclusion of demos would not only lead to improved student satisfaction in feedback evaluations, but also suggest that this type of active learning would aid in longer-term retention of knowledge relevant to their experiences in later clinical years. The primary objective of this study was to evaluate through surveys the effectiveness of the in-class demonstrations involving fluidics, which cover concepts that may be difficult to grasp just from reading or viewing recorded lecture alone (or even from cadaveric specimens in GrossLabs)—and instead retain greater value if taught with live demonstrations. A broader secondary goal was to inspire continued accrual of validated “better to be done live” demos to help guide future directions of knowing what topics are best taught face-to-face in large classrooms versus through lecture capture, flipped classes, small groups, or other formats.

Background and Design

A typical learner in a classroom setting can remain focused for an estimated 12–15 min before a need in change of venue [21]. Thus, the below demos were designed to be used judiciously part-way through traditional 1-h lecture slots. The genesis of the demos stems primarily from the author’s experience from attending chemistry and physics courses at an undergraduate level. Credit for the egg-in-bottle demonstration goes in part to the movie “Concussion” (2015, director Peter Landesman), which used a similar analogy to convey the mechanics of helmet-to-helmet collisions in American football. Each of the demos can either stand alone as a separate mini-lesson or be combined with other lessons as appropriate given time, content, and classroom constraints. However, it is recommended that they be used in the context of other teaching modalities, such as slide presentation. Given the fast pace of traditional lecture content delivery, the below demos are designed to be conducted relatively quickly, less they be perceived as “wasting time” by learners. They are also designed to be relatively fail-proof, safe, and viewable by learners seated anywhere in a large lecture hall. The demos are addressed briefly below, as a fluid dynamic theme, together with detailed lesson plans in the Appendices.

Teaching Method

Demo no. 1: Epidural Hematoma Formation—“The Baseball Bat Accident”

The Epidural Hematoma Formation demo lesson (Fig. 1; teaching time, ~ 8–10 min; also see Appendix 1 for details) illustrates how a patient may develop an epidural (or subdural) hematoma due to traumatic injury to the side of the head, such as an accidental baseball or baseball bat blow to the temple region. This illustration was designed for first-year medical students who are beginning to learn head and neck Gross Anatomy (just prior to Neurobiology topics). At this stage, students are being introduced to the learning objectives pertaining to identification of features of the scalp, skull, and meninges, together with learning about blood supply to the head. The present demo serves to enhance their understanding of dynamic actions and concepts of traumatic brain injuries to help focus their understanding of why detailed anatomy and terminology is being taught.

Fig. 1.

Epidural hematoma baseball bat demonstration. a–b Suggested materials to create the demo, detailed further in Appendix 1. c The demonstration (demo no. 1) in action on stage: one student holds a plastic bat to recreate the virtual head trauma. Two students hold the skull-apparatus simulating a piece of curved skull over the pterion and shower curtain inside as dura mater. d An additional “taller” student holds the milk container(s) filled with water and red food dye (to simulate blood) to eventually pour into the funnel (meningeal artery). Red water fills into the shower curtain area, bulges out, and provides a salient bi-crescent shaped visual of the hematoma formation

A classical head trauma worst-case situation is the “talk and die” scenario [22, 23]. In this classroom demo, a pee-wee league baseball game accident unfolds (bat hitting side of kid’s head), leading to blood buildup in the space between dura mater and skull. This demo interactively illustrates why a bi-crescent shape emerges with an epidural hematoma, and why it can be viewed as such in any plane of section with computed tomography (CT) or magnetic resonance imaging (MRI). In short, the baseball bat is swung by one volunteer (Fig. 1c) to hit the foam/skull at the pterion, which is a weak point of the human skull [24, 25]. Roughly 1.5 gal of red dyed water (blood) is poured into a funnel and red tube (middle meningeal artery via the foramen spinosum). Water extravasates the shower curtain (dura mater) away from the foam board (skull) developing into a large water-filled bi-crescent shape pouch (Fig. 1d) that is readily visible even from the back of a large room. This “classical” bi-crescent shape is shown (together with slides) to persist regardless of plane of section (coronal, sagittal, axial) when viewed with CT or MRI imaging.

Demo no. 2: Fluidics of the Cerebral Spinal Fluid System

The four below CSF-related demos are also presented around the time head and neck Gross Anatomy and/or Neurobiology are being first introduced in the course curriculum. They can be presented separately over weeks, but here presented as a collective. The basic content delivered was derived from clinical neuroanatomy textbooks [24, 25].

Part A (Fig. 2a; Appendix 2A) involves illustrating, via document camera, a skull (plastic bowl), dura mater (Cordura bag), arachnoid mater (green sponge mop head), pia mater (Saran wrap), and CSF (water), with a plastic brain model floating on these layers within the bowl—illustrating an “open” CSF system dissected out. Part B (Fig. 2b; Appendix 2B) demonstrates how the central nervous systems (CNS; brain plus spinal cord) basically floats within the skull/vertebrae when in a “closed” CSF system: This involves floating a dye-colored boiled egg (brain) in a jar filled with salt water (skull plus CSF). The egg floats regardless of jar orientation (e.g., lying down or doing a head stand). Part C (Fig. 2c; Appendix 2C) introduces an intuitive understanding of the mechanics of a lumbar puncture (“spinal tap”) of a closed CSF system. A solid sphere (brain) is set upon a water fountain waterspout (pressurized CSF system) and the sphere floats and begins to rotate—which is easily viewed by the entire class via document camera. A lumbar puncture is simulated by turning off the water pump (removing CSF pressure) which immediately causes the sphere to dramatically stop floating and sink into the spout (foramen magnum), typically leading to a headache for the patient. Later, in the presentation, the fountain can be turned on/off again as CSF is reconstituted (at a rate of ~ 500 ml/day) and back to normal intracranial pressure (ICP). Various pathologies involving ICP changes and contraindications for lumbar punctures may also be introduced at this point.

Fig. 2.

Demonstrations related to cerebral spinal fluid system integrity. a Materials for brain floating in CSF and meningeal layers, which are for use with a document-camera. b Materials for egg (“brain”) floating in a jar filled with saltwater (“CSF”). c Photograph of a solid sphere (brain) being floated/suspended on water fountain (CSF), illustrating how the intracranial pressure of an intact CSF system effectively allows the brain to float, and thereby provide protection (demo no. 3, part C). d Raw egg (brain) in bottle filled with water (CSF), and a student in class violently shakes the jar to crack the egg—but fails (demo no. 2). Refer to Appendix 2 for further details

Part D (Fig. 2d; Appendix 2D) re-introduces part B but with a raw egg inside a jar filled with water. Seated volunteers, including shy ones near the back of the room, are sought out and invited to try to crack the egg by violently shaking the jar (on stage or at their seat). Provided there is no air in the jar, the egg (brain) should not break, illustrating the protective qualities of an intact closed (and pressurized) CSF system. The egg is removed and cracked open after the demo to show that it was indeed raw (can be done with dramatic flair).

Methods

Two sets of anonymous survey data were collected online from two different populations: first-year medical students at the end of the medical neurobiology course (M1) and fourth-year medical students who have completed much of the clerkship curriculum (M4). Approval for this study’s assessments, adhering to standard educational practices, was granted by West Virginia University Institutional Review Board (WVU project number no. 1907637152). The 17-item, non-validated survey included a section in which all participants were asked to respond to questions about observed demonstrations in class (Appendix 3). Questions specifically targeting the teaching demo effectiveness included a 5-point Likert rating scale for each of the 10 in-class demos taught throughout the course. One open-ended question was also asked to allow participants to anonymously comment on their reflections. Surveys were collected using E*Value [26]. Data were collected and analyzed using a thematic analysis focusing on the students’ subjective experiences while observing the demos in class and individual non-structured interviews. Coding was conducted manually and independently, by two authors, using an inductive thematic approach to free-text responses, and final themes with supporting quotes were developed. Differences in ratings by medical student cohorts were assessed using t tests.

Results

General Description of Study

With regard to the efficacy of the on-stage fluidic demonstrations under investigation in the present study, 219 M1 surveys were distributed electronically over the course of two academic years (2018 and 2019, respectively); and 215 were returned completed (98% response rate: 108 of the responses were from the class of 2022 and 107 from the class of 2021). Second, 106 were distributed to M4 students (who took the course in 2017) using a subset of the same question that were relevant to the present study, and 34 were returned completed (32% response rate).

Quantitative Data Analyses

Likert scale ratings (1 to 5) of demonstration effectiveness were collected from both M1 and M4 student cohorts in response to questions pertaining specifically to three of the in-class demonstrations (Table 1). In general, a rating above a 4 or higher (of 5) was historically considered to be very good among these respondents based on other questionnaires. A rating in the 3 to 4 range was viewed as being in need of significant improvement. Thus, the M1 ratings (Table 1A; all above 4) were suggestive of students finding these demonstrations immediately useful for preparation for institutional and national exams taken at the end of the course. For demo no. 1, the M4 ratings (Table 1B) were nearly identical to those by the M1 cohort (unpaired two-tailed t test₍₂₀₄₎ = 0.05, p < 0.95), indicating that this was a reliable measure over time. For demo no. 2, however, the M4 ratings were significantly lower than the M1 cohort (unpaired two-tailed t test₍₂₀₈₎ = 2.17, p < 0.03). Similarly, demo no. 3 ratings were also significantly lower for the M4 versus M1 cohorts (unpaired two-tailed t test₍₂₀₈₎ = 3.02, p < 0.003). Note that over the years between when the M1 and M4 respondents had taken the course, each of the three on-stage demonstrations queried had undergone refinements for improvement. Thus, it was not clear whether the lower M4 ratings were due to differences in on-stage performance, to memory retention more generally, or a reduction in its perceived clinical relevance after clerkship rotation experiences (see “Discussion”).

Table 1.

Frequency and percentages of student responses to three of the teaching demo survey questions about effectiveness. Respondents were surveyed about the effectiveness of in-class educational demos immediately after the course, according to engagement, relevance to material, and likeliness for long-term retention of material. This included (A) 1st year medical students (M1; n = 185 of 215 combined from two class years of cohorts), and (B) 4th year students (M4; n = 34 of 106) who had completed the course roughly 3 years earlier. Respondents picked the demonstrations they observed in class and provided a rating for each only if they were in class during the demo. This table shows the top three high ranked demonstrations of the present study. Demo #1 = Epidural Hematoma & Baseball Bat; Demo #2 = Egg in Bottle (Brain protection & Concussion); Demo #3 = Water Fountain Floating Sphere & Lumbar Puncture, specifically Part C—the mechanics of the lumbar puncture

	Effectiveness rating
	Not		Neutral		Extremely
DEMO	1 n(%)	2 n(%)	3 n(%)	4 n(%)	5 n(%)	AVG	STD
A. M1
Demo no. 1, n = 175	3 (1.71%)	5 (2.86%)	13 (7.43%)	47 (26.86%)	107 (61.14%)	4.43	0.88
Demo no. 2, n = 182	3 (1.65%)	4 (2.20%)	25 (13.74%)	62 (34.07%)	88 (48.35%)	4.22	0.90
Demo no. 3, n = 185	5 (2.86%)	4 (2.29%)	28 (16%)	62 (35.43%)	86 (49.14%)	4.14	0.96
B. M4
Demo no. 1, n = 31	0 (0%)	0 (0%)	4 (12.9%)	10 (32.26%)	17 (54.84%)	4.42	0.72
Demo no. 2, n = 28	0 (0%)	2 (7.14%)	8 (28.57%)	10 (35.71%)	8 (28.57%)	3.86	0.93
Demo no. 3, n = 25	1 (4%)	3 (12%)	8 (32%)	7 (28%)	6 (24%)	3.56	1.12

Qualitative Data Analyses

Qualitative responses were viewed and could be broadly categorized into three main themes for the M1 and M4 students, including (1) in-class engagement, (2) long-term retention, and (3) a clinical connections theme unique to the M4 students. Figure 3 depicts the M4 student responses for which clerkship(s) the in-class demonstrations were deemed to be useful or effective. The following sections describe the results by theme.

Fig. 3.

Number of M4 student responders which identify utility of the in-class demonstrations in specific clerkships. Respondents were 34 of 60 fourth-year medical students, surveyed about which clerkships they applied in-class educational demonstration concepts largely from the Medical Neurobiology course. Each bar shows the number of respondents applying the in-class demonstration knowledge in their clerkships. Respondents could indicate more than one clerkship as students had typically completed 6–7 clerkships at this stage of their education

Student Comments

Theme 1: In-class Engagement

The first theme that emerged was the increase of in-class engagement and student participation. Students described in detail how engaging and entertaining the educational demonstrations were in connection to content presented. Narrative comments from participants indicated the effectiveness of the demonstration in holding their attention and providing a visual learning experience that is not always clearly attained through recorded lecture [15, 19]. There is a direct association to be made with the material learned with “generation Z,” such as physically seeing how the brain floats within CSF, where the teacher thinks critically and creatively about presenting new knowledge in the classroom [12]. To this end, some students felt that they were able to quickly grasp the concepts and save time studying. Example quotes that were characteristic of this theme includes:

• M1, S11: As a student who has a tendency to get distracted and space out during lectures, the demonstrations really helped me focus my attention because they were fun, a tad unusual, and engaging…I think what made these demonstrations most effective in enhancing my learning of this material was the fact that they fulfilled my need for information to be solidified in multiple sensory systems. I know for a fact that I am able to remember information more clearly if I read it, write it, hear it, and see it. These demonstrations provided me with an opportunity to both see and hear these pathways explained in metaphor and in reality, and I think that significantly enhanced my ability to retain the information.

• M1, S8: I’m usually a Camtasia [Recorded Lecture] person because I usually have to pause, rewind, and review certain parts, but I loved coming to [the Instructor’s] lectures because he was so engaging and interactive, and I could stay focused throughout his whole lecture. He would take time to fully explain things, so I could keep up in class. The water fountain floating and spinal tap was my personal favorite because I was struggling to understand that concept, and now I’ll never forget it.

Theme 2: Long-term Retention

Many students commented on the design of the demonstration in achieving overall recall and long-term memorization of learning concepts connected to exam questions. In regard to this theme, some of the student (S) respondents noted:

• M1, S18: The involvement of my classmates made the “in-class educational demos” memorable! I feel like I can remember my classmates and their roles in the demos, therefore helping me recall what the different aspects of the demo were. I also think that even though I do not always learn during the demo, when I’m reviewing the lecture, I can tie it back to the demos and facilitate my memory of the concept.

• M1, S55: I always appreciate a visual reference to look back on when taking an exam to remember information. The hematoma & baseball bat demo was one that came to mind when I was taking the shelf exam yesterday.

• M1, S34: These demonstrations were effective because they were memorable. Every time I saw a question about head trauma to the side, I pictured my classmate swinging the baseball bat and the blood running through the apparatus.

• M4, S5: The demo on epidural and subdural hematomas was effective because we were actually seeing how our classmates would have been directly affected in the clinical scenarios and linking the presentation to the pathology.

Theme 3: Clinical Connections

M4 respondents provided a retrospective review of how the in-class demonstrations had contributed to their recollection 1 year after they had opportunity to interact with patients in clinical settings. Comments indicated the utility of the demonstrations in achieving longer-term retention through medical school. Regarding this theme, respondents noted:

• M4, S17: Probably medicine [clerkship] the most because we did a lot of neuro exams and it’s much easier to remember the neuro exam if you have some idea of why you are doing the exam.

• M4, S5: Imagining clinical scenarios in which you could trace it to the pathology was very effective (e.g. how you could get an epidural or subdural hematoma and why they would present in those ways).

• M4, S11: The epidural hematoma demo was memorable due to the traumatic smack with the bat and the classic presentation of trauma with the classic presentation.

Discussion

Our findings from different medical student group populations, in different training settings, revealed that live in-class demos were indicative of fostering positive learning engagement associated with long-term retention of material. The input further provided instructors with substantial opportunity to improve approaches to teaching and learning. Given the ever-changing nature of lesson design and the education environment, recommendations for future research could focus on further investigating current trends in pedagogical practice. The first-year medical curriculum is often packed with a wide variety of high-yield topics that does not always allow for learners to acquire a deeper or intuitive understanding of many of the topics. Our findings may serve as an impetus for clinical and non-clinical educators to move beyond the traditional lecture (~ 1 h) modality, explicitly focus on ways to engage their student learners in the classroom, and discuss varied learning design approaches that transform curriculum [27]. Enabling instructors to perform on-stage demos, such as those of the present study, should help encourage the creation of a stage learning environment that fosters the instructors’ confidence, and thus improve (or help impart) a positive, confident attitude to which students respond favorably. The Likert-rated questions and student comments suggest that the in-class educational demos are an important tool in long-term retention of high-yield material. The comments from the M1 and M4 surveys provided us with insights of how these demos commit to long-term memory lasting into later clinical years: In support of earlier research, an important part of the demos was to connect the material through more of a learner-centered approach [28], wherein students were doing more discovery-related learning, even if only by proxy through their peers in large-classroom settings.

We had identified three themes that were consistent with research on effective teaching methods. These themes could serve as a basis for educational teaching practices in medical schools interested in improving the traditional classroom lecture. While the demos were designed for medical anatomy courses, several points are transferrable to other content. First, in-class demos are most effective when they are short in duration (2–10 min) and simple in design. Demos do not always require lengthy explanations. Keep it simple through a summary and one or a few PowerPoint slides. Second, engage the audience with large, exuberant props. The demos will ideally enlarge the concept on a grandiose scale. Make use of different materials (e.g., supplies from a garage or local hardware store, water features, audio animations) that may involve more senses to aid learners in understanding the concept presented. Note, however, the demo(s) can quickly become overwhelming or ineffective if there are too many props, as suggested by the following comments in general regard on-stage demos we received:

• M1, S54: Some were too elaborate for me to understand like the cochlea and the circle-of-willis, even though I enjoyed the comedic effect. But other things like the egg in a bottle and spinal cord lab were perfect for my learning style

• M1, S55: I think the best way to learn is with clinical scenarios or being actively involved…Other than that, I am not helped by extravagant, multi-step demos, they are hard to apply back to material.

Third, perform the large class demo with student volunteer engagement when possible. The purpose of the demos was to engage an audience while avoiding the monotony of a didactic lecture. The use of student participants should focus the attention on the lesson, evoking prior learned material, assimilating information, and inspiring group discussions about the demo. Medical education literature indicates a growing interest in approaches to student participation such as co-design, student engagement, and design partners [29–32]. Allowing students to play an active role as demo design partners and/or contributors to placement of demos within the course curricular sequence helps students to implicitly understand the theoretical background and structure of the content and placement of the demos. Moreover, it allows students to shape their learning opportunities in medical school and create a culture of empowerment, as opposed to a purely passive role.

Limitations, Considerations, and Future Directions

While our study highlights innovative teaching tools to engage the classroom learner, there are several limitations to be considered. First, we invited M4 students to participate in the survey and thus a relatively small “n” count is present for this data population. Secondly, there was no opportunity to investigate motivational strategies for learning questions before and after the course [33, 34]. Nor was there any means for contrasting the effectiveness of teaching with versus without use of the on-stage demonstrations due to the course regulations and architecture. This precluded analyses for understanding whether there was a statistical significance between the groups of students who attended and those who did not attend the in-class demo day. For example, does a student that observes the in-class demo live have an advantage? Did the in-class demos on CNS lend themselves to statistically significant improvements in student retention of CNS fluid dynamic material test questions? Additionally, the Table 1 data was necessarily biased to reflecting short-term effectiveness and student satisfaction ratings, which may not accurately reflect long-term and overall learning/teaching effectiveness [35]. Finally, the demos underwent continued development and refinement (and practice) over the years, such that the M4’s experience with them would have been slightly different from the more recent M1 cohorts.

Another limitation was that because the questionnaires were anonymous, and were from different class years, we were not able to perform any repeated measure analyses to distinguish short-term/satisfaction biases from true longer-term retention effectiveness results. Nonetheless, these results suggest that the teaching demonstrations were supportive in creating an engaging learning environment. This study was conducted to quantify the learning effectiveness of these kinds of on-stage, large class interactive lecture demonstrations (ILDs) in a medical curriculum. Based on the longer horizon M4 comments, showing up to class for the live demonstrations certainly appears to have been worthwhile, and presumed to convey information beyond their recorded (audio and slide) substitute, which ultimately made the clinically relevant material more memorable over the longer term.

Conclusion

The use of on-stage demonstrations to break up the monotony of traditional 1-h lectures suggest short-term retention and motivation for learning held value even roughly 3 years later, after medical students had experience with seeing patients in clinics. Student comments indicate live attendance was viewed as being better than lecture capture in that comments reflected how students recalled seeing their classmates on stage and/or doing active learning. These and other growing contributions to medical curriculum teaching will help guide what concepts may best be taught live, face-to-face (as opposed to lecture capture), even in flipped and mixed classroom settings. Coupling these on-stage demonstrations with other teaching methods should help support a more engaging learning environment and perhaps reveal a more complete picture of generation Z student learning preferences.

Appendix 1

Title: Epidural Hematoma Formation: “The Baseball Bat Accident”

Estimated Time: One 10-minute session.

Lesson Author: Dr. James W. Lewis, PhD, West Virginia University Department of Neuroscience.

Learning Objectives:

1. Describe the mechanics of how an epidural hematoma forms.

2. List and explain key anatomical structures, including the pterion, middle meningeal artery, foramen spinosum, dura mater, arachnoid mater, extravasation.

Resources & Materials, (also see Fig. 1)

• One 3x3 feet sheet of white, hard, waterproof foam padding to simulate a piece of curved skull over the pterion

• One transparent, colorless shower curtain

• One tube of watertight sealant. Roughly, 5 feet of red colored PVC tube with a funnel and stopcock (available at most party stores)

• One children’s plastic baseball bat

• One gallon and one ½-gallon milk container filled with water and red food dye (to simulate blood)

• One 2x4 foot under-the-bed storage unit (to capture any leaks and to store materials)

Preparation

1. If your classroom does not have space for the demonstration, arrange for class time in another room.

2. Labels can be placed on the model, including the “pterion”, skull sutures, “foramen spinosum” where the red tube (middle meningeal artery) penetrates the skull (Fig. 1) before class.

3. Between the shower curtain and foam, slide in one red tube and add split (bifurcation) of tubing for an anterior middle meningeal artery and a separate piece or two of tubing to show a “rupture” of the artery—this is hidden from audience’s view until after the “accident” occurs on-stage.

4. Provide safety goggles for the student swinging the bat, at least for dramatic effect. All wet items can be tossed into bin and quickly removed for later clean up.

5. Be sure to have a mop or towels on hand to clean up any fluid mess during break after class, and/or place a “caution” placard for additional dramatic effect. If the manipulandum leaks, use this to your advantage as a teaching moment to highlight a mix of epidural and subdural bleeding. Regardless of in-class outcome, the attempt of performing this demonstration will be remembered longer-term, while details can be read or referenced at a later time.

Instructional Plan:

1. Begin by selecting two students to hold the skull—one tall student to pour blood/water into tubing through funnel, and one student to swing the bat to simulate a baseball game “accident”.

2. Ask the student to swing the baseball bat towards the foam at the pterion (Fig. 1c), which is a weak point of human skull [24, 25]. Make sure this is loud and play up the drama to attain full class attention and anticipation.

3. Tell the students the following, “The middle meningeal artery has been ruptured. Predict what you think will happen next.” (Take a few predictions out loud.)

4. Next, have the two students turn the model around to reveal the ruptured meningeal artery (Fig. 1d)

5. Elevate the red tube with funnel and have a tall student pour in the blood/water. The shower curtain should hold and begin to fill creating a bi-crescent shape between the white foam/skull and dura mater/shower curtain.

6. After a gallon or so has filled, point out how in any plane of section a CT or MRI scan would show a bi-crescent shaped hematoma. The teacher will explain how this is a classical epidural hematoma. Note that if the shower curtain were to break/leak (a potentially humorous moment on stage), this would represent a subdural hematoma or a mix of the two (which actually is relatively common, but not as elegant to demonstrate or assess on Board exams).

7. Follow up the demonstration by showing CT or MRI scans of classical epidural hematoma relative to a subdural hematoma, ideally from required or suggested textbook reading assignments.

8. Invite students to discuss the demonstration with the follow up questions to assess learner understanding of material:

   1. Explain why an epidural hematoma has a ‘bi-crescent’ shape?
   2. What would a CT scan of a subdural hematoma look like?
   3. Based off of this demo, describe how a hematoma might affect intracranial pressure?

STUDENT ASSESSMENT/REFLECTION

Students can be assessed through their in-class discussions and participation.

Appendix 2

Title: Cerebral Spinal Fluid (CSF) System Integrity

Lesson Author: Dr. James W. Lewis, PhD, West Virginia University, Department of Neuroscience.

Learning Objectives:

1. Describe the mechanics of how the CNS (brain and spinal cord) are effectively floating in the dura and skull/vertebrae.

2. Describe how the closed CSF-system affords protection from impact.

3. Explain the mechanics behind headaches formation resulting from CSF leakages, including a lumbar puncture.

Resources & Materials (also see Fig. 2)

Part A

• 1 white plastic bowl

• 1 Cordura bag

• 1 green sponge mop head

• 1 towel to clean up liquid

• Saran wrap

• Plastic brain model

• Document camera or device to view the demo throughout the classroom

Part B

• 1 red dyed, hard-boiled egg (from convenience store)

• Small glass jar with lid (to fit egg)

• Water plus 1-2 tablespoons salt (mix until roughly buoyant for egg)

Part C

• Floating sphere in fountain (desktop water fountain, available online, under $40)

• One surge protector with on/off switch and extension cord (Fig. 2c).

Part D

• One small transparent jar with lid, filled with tap water

• One raw egg

Preparation

1. If your classroom does not have a document camera already, arrange for the provision of one or some form of projection so all students can see it (Fig. 2a, c)

Instructional Plan: Part A illustrates an opened CSF-system, followed by Part B to illustrate mechanics of a closed CSF-system, can be implemented during one lecture using a document-camera to project the apparatus. Part C and D can be implemented during that lecture or on later lecture days/weeks, each time going out into the audience and engaging active recall.

Part A: How the CNS (brain and spinal cord) floats (~2 minutes)

1. Obtain a white plastic bowl (skull), with Cordura bag cut open (dura mater), with green sponge/mop (arachnoid mater), Saran wrap (pia mater) covering a model brain.

2. Place water in Cordura layer with sponge to simulate CSF and float brain-pia mater on sponge (Fig. 2a).

3. Use a document camera projection to illustrate that the brain “floats” in these tissue layers.

Part B: “Egg in Jar Floats” (~2 minutes) - Reinforcing an intuitive understanding of the mechanics of a lumbar puncture (“spinal tap”) in a closed CSF-system

1. This option includes placing a red dyed hard-boiled egg in a small transparent glass jar with lid, which is filled with salt-water (Fig. 2b). The idea is simply to extend the concept that the brain (egg) when placed into a buoyant fluid (“CSF” in jar) will float regardless of orientation of the jar.

2. The colored egg (typically red pickled eggs from gas station) are highly visible even when viewed from the back of the room.

3. Turn your head 90 degrees as if simulating sleeping, and turn the jar 90 degrees to the side, and note that the egg/brain still floats.

4. Ask class, “Describe what might happen if you did a handstand, turning the jar 180 degrees upside down. What will happen to the egg/brain+spinal cord?”

Part C: “Solid sphere floating on water fountain” (~2 minutes) - Demonstration of how the brain may sink into the foramen magnum during a lumbar puncture.

1. Prior to demonstration, fill the fountain with water (Fig. 2c), place under the document-camera system, and test that the power strip at the lectern can turn the fountain off and on readily.

2. One may presage the Part 2C demonstration by introducing the concept of a lumbar puncture (“spinal tap”), why a patient might need one, and/or contraindications.

3. Extending the concept from Part A, at lecture hall tap the solid sphere on tabletop to demonstrate that it’s solid. Turn on document camera.

4. Ask the class, “Predict what will happen when you place the solid sphere onto the waterspout?” (“pressurized CSF” system).

5. The sphere floats and begins to rotate, which is easily viewed.

6. Next ask the class, “Predict what happens when too much CSF is removed too quickly during a lumbar puncture.” To simulate this, turn off the pump and the sphere dramatically stops rotating/floating and sinks into the spout (foramen magnum). This leads to an instant headache.

7. Have your patient lie on their side to relieve the pressure, allowing the brain to float in the lateral surface of the skull/calvarium. Inform them that a patient should then wait 15 minutes or so until the CSF fluid has sufficiently reconstituted. Reiterate that CSF production is continuous, as it oozes out of the choroid plexus and ependymal cells lining the ventricles.

8. One can state factoids about how much CSF is produced daily, how much is in the head at any one time. Invite students to discuss the demonstration with the follow up questions to assess learner understanding of material:

   1. What pathologies related to hydrocephalous conditions can be introduced?
   2. Indicate how and why a space occupying lesion (e.g. hemorrhagic stroke) might present as a life-threatening condition through mass effect.
   3. Describe CSF composition and how to read clinical tables that are typically provided on NBME National Board exams.

Part D: “Shake egg in bottle” which does not break (~2 minutes). Demonstration of how a closed-CSF system protects the brain and cord from concussion/damage during violent impacts. This standalone demonstration works well after Parts A-C above.

1. Begin by having the students recap the “egg in jar floats” demonstration from Part B.

2. Next state that you have a raw egg and place the egg in a topped off jar of water (Fig. 2d).

3. Quickly place the lid on to avoid air pockets. Wipe dry. Select a couple of students, ideally shyer ones near back of room to garner learner-centered attention, to try to violently shake the jar to “crack the egg” inside (without impacting the jar onto a surface). Humor will naturally develop with this approach: Run with it, as this is what will instill longer-term retention of the related didactic concepts.

4. One can play upon American football scenarios and/or the movie “Concussion”, which uses a similar scenario to illustrate the concept of chronic traumatic encephalopathy (CTE).

5. Return to front of the room. Assuming no one could crack it, remove egg from bottle and crack it open (or fully open) into a pan to demonstrate that the egg was indeed raw (for dramatic effect).

6. Extending components of the demonstrations throughout a lecture can be more effective than showing this all at once. This leads to anticipation about what is coming up later in the lecture, and you can teach other content between demonstrations. Be certain the ‘plumbing’ is operational prior to lecturing, as having to fix an apparatus during lecture does not come across well. Have a “caution wet floor” placard and few towels on hand in case of spillage, and to facilitate possible clean up.

STUDENT ASSESSMENT/REFLECTION

Students can be assessed through their in-class discussions and participation.

Appendix 3

Survey Asking Respondents About In-Class Educational Teaching Demos. The below image shows question #14 (of a full survey with 17 questions) to which both the M1 and M4 student cohorts responded. This question included ten “live” demonstrations to be rated, and numbers 5 (Demo #2), 6 (Demo #1), and 10 (Demo #3) were those addressed in the present study.

Compliance with Ethical Standards

Conflict of Interest

The authors declare that they have no conflict of interest.

Ethical Approval

The study received WVU Project Number No. 1907637152 (see Methods).

Informed Consent

NA