Creating cartoons to represent habitual leg movements

Abstract Many people have a habit of moving their legs and believe that this behavior is due to the restless legs syndrome (RLS), a highly prevalent neurological condition that greatly impairs the quality of life of affected individuals. This behavioral pattern, characterized by the habit of moving one’s legs and feet, may be an important confounding factor in the diagnosis of RLS. Objective: To describe the main movements associated with this benign behavioral state to characterize a possible clinical condition that can contribute to the differential diagnosis of RLS. Methods: Experienced sleep specialists, who primarily see RLS patients listed the most frequent movements people without RLS report while describing their suspected RLS. We first compiled a list of the lower-limb movements described by the specialists. Then, one of the authors (KC) carried out all movements of the list on camera to obtain a video footage. This footage was sent to one of the authors, EPC, who, alongside a group of students, drew graphic representations (cartoons) of the recorded movements. Results: The panel of sleep experts described 13 leg movements commonly reported by their patients. The experts reported 11 simple movements and two combined movements. Conclusion: In this study we developed an instrument that allows us to oppose and distinguish a pathological condition (RLS) from a behavioral phenomenon. This state of behavioral leg fidgeting needs to be better characterized and may eventually be recognized as a clinical entity per se .


Creating cartoons to represent habitual leg movements
associated with an unpleasant sensation that occurs during rest, especially in the evening and night, which improves with movement and cannot be explained by other clinical or behavioral conditions 1,2 .
As movement is a core clinical feature of RLS, there may be some difficulty in distinguishing the disease from the nonpathological habit of leg fidgeting in various everyday situations 3 . In addition, the presence of the word "restless" in the name of the disease may suggest that repetitive movements are enough to characterize it, even though restlessness alone is not enough to define RLS/WED 4 . Diagnostic criteria have been updated over the years, and the expression "motor restlessness", for example, has been replaced by an "urge to move", demonstrating the concern of the IRLSSG to specify the reason why affected individuals perform these movements 2,5 .
In RLS/WED, leg movement is an important, imperative factor without which the individual cannot relieve the uncomfortable symptoms they experience. In the non-pathological behavior pattern, legs movement merely represents a habit; it does not serve the purpose of reducing or abolishing any discomfort or symptom felt in the legs 6 . On the other hand, individuals often move their legs without being fully aware of the movement or of the reason behind it, although it "feels good". Some movement patterns have been more clearly described in the differential diagnosis of RLS 3,7 , including, for example, hypotensive akathisia, painful legs and moving toes, and neuroleptic-related akathisia 8 . However, to date, no studies have described and clearly characterized the movements associated with the benign behavioral state of leg fidgeting, which is often confused with RLS, not only by physicians but also by the general population, contributing to diagnostic errors and stigmatization of RLS patients, respectively.
The purpose of this study is to describe the main movements associated with this benign behavioral state to characterize a possible clinical condition that can contribute to the differential diagnosis of RLS.

METHODS
Experienced sleep specialists, who primarily see RLS patients, listed the most frequent movements that people without RLS report while describing their suspected RLS. In view of the difficulty of describing some movements, one of the authors (KC) asked the participating experts to imitate the movements reported by patients. We attempted to classify those reported movements according to the moving joint, side, and posture of the legs.
This study was carried out jointly with students of the Design program of Universidade de São Paulo, School of Architecture and Urban Planning (FAU-USP) and was approved by the Research Ethics Committee of Universidade Federal de São Paulo (UNIFESP).

Cartoons
We first compiled a list of the lower-limb movements described by the specialists. Then, one of the authors (KC) carried out all movements of the list on camera to obtain a video footage. This footage was sent to one of the authors (EPC), who, alongside a group of students from USP Design program, drew graphic representations (cartoons) of the recorded movements. These cartoon representations should be simple and easy to recognize, to ensure applicability in future population-based studies. We used this criterion to select the best set of cartoons.

Selection of cartoons
Two authors (GFP and KC) analyzed the proposed cartoons and chose the set that best met the afore mentioned criteria of simplicity and ease of recognition.

Classification of movements
We classified movements as "simple" when they involved only one joint, whether unilaterally or bilaterally. Conversely, we classified those movements in which two or more joints were actively involved as "combined".

Movement recognition test
The selected set of cartoons (Figures 1 and 2) was presented to five neurologists who were participating in a Sleep  Medicine fellowship program. The fellows were then asked to reproduce the illustrated movements. These physicians had not participated in any previous stage of the study.

RESULTS
The panel of sleep experts described 13 leg movements commonly reported by their patients, listed below according to the lower limb joints involved. The experts reported 11 simple movements (Table 1) and 2 combined movements ( Table 2).

Selection of cartoons
We received 19 sets of cartoons and selected only one set, which represented the movements clearly and was easily interpreted. Even so, Movements 2, 3, and 4 were somewhat difficult to recognize (supplementary data).
In Movement 2, the cartoon gave the impression of four feet, as the legs were drawn very close to each other and the shading confused the actual movement, suggesting there were two feet moving up and two, moving down. In Movement 3, the left heel was not visible in the cartoon and the arrows were not aligned with the corresponding feet to indicate movement. In Movement 4, the shading of the cartoon was deemed confusing, making the interpretation of the Table 1. Simple movements.

Movement
Description Figure   1 Tapping  left lower limb position difficult. These issues were addressed, and a definitive set of figures was developed (Figures 1 and 2). All sleep medicine fellows who participated in the movement recognition stage had no difficulty reproducing any of the movements correctly.

DISCUSSION
The main result of this study was the creation of an adequate visual representation of the movements most  commonly reported by individuals who experience habitual leg fidgeting. The movements were easily identified even in version one of the set of cartoons; only movements 2, 3, and 4 required clarification, and, in the final version, were very clear and easy to recognize.
This study is an important step toward the creation of an instrument designed to differentiate patterns of movement associated with the benign habit of leg fidgeting from those of RLS/WED, a pathological condition with clinical consequences and impact on quality of life [9][10] .
These cartoons may be part of future population-based studies aimed at identifying and increasing awareness of a phenomenon that is often mistaken for RLS/WED. Patients with RLS are stigmatized because, from the point of view of the general population, a medical diagnosis of RLS represents only the habit of moving one's legs, which we have termed as leg fidgeting -something that is far from representing a problem 1,9 . Friends and family often do not understand why patients with RLS need to take medications, as they presume they also have "restless legs" and cope well with it. People with this habit cannot see RLS as a real health condition, since they confuse the disease with benign leg fidgeting.
One weakness of this study is that our option for simplicity and lightness of the drawings could bring some difficulty of representation. The number of medical specialists interviewed was small, and no specialists from large cities were interviewed. An advantage of the present study was the use of simple lines and the aid of direction signals outside the drawing, making the drawings simpler and less numerous.
In summary, in this study we developed an instrument that allows us to oppose and distinguish a pathological condition (RLS) from a behavioral phenomenon [3][4][5][6][7] . This state of behavioral leg fidgeting needs to be better characterized and may eventually be recognized as a clinical entity per se.