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A patient would contract surface muscles as a
reaction called muscle guarding when experiencing discomfort
and pain during physical palpation. This reaction carries
important information about an affected location. Training
physicians to regulate palpation forces to elicit just enough
muscle guarding is a challenge using real patients. Tunable
stiffness mechanisms enabled by soft robotics can be effectively
integrated into medical simulator designs for effective clinical
education. In this paper, we propose a controllable stiffness
muscle layer to simulate guarding for abdominal palpation
training. Designs with soft, fine and rigid granular jamming,
stretchable and non-stretchable layer jamming mechanisms
were tested and evaluated as methods to create controllable
stiffness muscle. User studies have been carried out on 10 naive
participants to differentiate the guarding and non-guarding
abdomen with the proposed jamming mechanisms. Muscle
samples made of ground coffee (fine granular jamming) and
latex layers (stretchable layer jamming) show good usability
in simulating abdomen with different stiffness with average
success detection rate over 70% for both tested palpation
gestures (single finger and multiple fingers) after short pretraining.
A multi-material 3D printed soft actuator is presented that uses symmetrical, parallel chambers to achieve bi-directional variable stiffness. Many recent soft robotic solutions involve multi-stage fabrication, provide variable stiffness in only one direction or lack a means of reliably controlling the actuator stiffness. The use of multi-material 3D printing means complex monolithic designs can be produced without the need for further fabrication steps. We demonstrate that this allows for a high degree of repeatability between actuators and the ability to introduce different control behaviours into a single body. By independently varying the pressure in two parallel chambers, two control modes are proposed: complementary and antagonistic. We show that the actuator is able to tune its force output. The differential control significantly increases force output with controllable stiffness enabled within a safe, low-pressure range (\(\le 20\) kPa). Experimental characterisations in angular range, repeatability between printed models, hysteresis, absolute maximum force, and beam stiffness are presented. The proposed design demonstrated a maximum bending angle of 102.6\(^\circ \), maximum output force 2.17N, and maximum beam stiffness 0.96mN m\(^2\).
Recent technological advances in robotic sensing and actuation methods have prompted development of a range of new medical training simulators with multiple feedback modalities. Learning to interpret facial expressions of a patient during medical examinations or procedures has been one of the key focus areas in medical training. This article reviews facial expression rendering systems in medical training simulators that have been reported to date. Facial expression rendering approaches in other domains are also summarized to incorporate the knowledge from those works into developing systems for medical training simulators. Classifications and comparisons of medical training simulators with facial expression rendering are presented, and important design features, merits and limitations are outlined. Medical educators, students and developers are identified as the three key stakeholders involved with these systems and their considerations and needs are presented. Physical-virtual (hybrid) approaches provide multimodal feedback, present accurate facial expression rendering, and can simulate patients of different age, gender and ethnicity group; makes it more versatile than virtual and physical systems. The overall findings of this review and proposed future directions are beneficial to researchers interested in initiating or developing such facial expression rendering systems in medical training simulators.
Jamming is a popular and versatile soft robotic mechanism, enabling new systems to be developed that can achieve high stiffness variation with minimal volume variation. Numerous applications have been reported, including deep-sea sampling, industrial gripping, and use as paws for legged locomotion. This review explores the state-of-the-art for the three classes of jamming actuator: granular, layer and fibre jamming. We highlight the strengths and weaknesses of these soft robotic systems and propose opportunities for further development. We describe a number of trends, promising avenues for innovative research, and several technology gaps that could push the field forwards if addressed, including the lack of standardization for evaluating the performance of jamming systems. We conclude with perspectives for future studies in soft jamming robotics research, particularly elucidating how emerging technologies, including multi-material 3D printing, can enable the design and creation of increasingly diverse and high-performance soft robotic mechanisms for a myriad of new application areas.
This paper provides a solution for fast haptic information gain during soft tissue palpation using a Variable Lever Mechanism (VLM) probe. More specifically, we investigate the impact of stiffness variation of the probe to condition likelihood functions of the kinesthetic force and tactile sensors measurements during a palpation task for two sweeping directions. Using knowledge obtained from past probing trials or Finite Element (FE) simulations, we implemented this likelihood conditioning in an autonomous palpation control strategy. Based on a recursive Bayesian inferencing framework, this new control strategy adapts the sweeping direction and the stiffness of the probe to detect abnormal stiff inclusions in soft tissues. This original control strategy for compliant palpation probes shows a sub-millimeter accuracy for the 3D localization of the nodules in a soft tissue phantom as well as a 100% reliability detecting the existence of nodules in a soft phantom.
This paper describes a multi-fingered haptic palpation method using stiffness feedback actuators for simulating tissue palpation procedures in traditional and in robot-assisted minimally invasive surgery. Soft tissue stiffness is simulated by changing the stiffness property of the actuator during palpation. For the first time, granular jamming and pneumatic air actuation are combined to realize stiffness modulation. The stiffness feedback actuator is validated by stiffness measurements in indentation tests and through stiffness discrimination based on a user study. According to the indentation test results, the introduction of a pneumatic chamber to granular jamming can amplify the stiffness variation range and reduce hysteresis of the actuator. The advantage of multi-fingered palpation using the proposed actuators is proven by the comparison of the results of the stiffness discrimination performance using two-fingered (sensitivity: 82.2%, specificity: 88.9%, positive predicative value: 80.0%, accuracy: 85.4%, time: 4.84 s) and single-fingered (sensitivity: 76.4%, specificity: 85.7%, positive predicative value: 75.3%, accuracy: 81.8%, time: 7.48 s) stiffness feedback.
Soft robotics for medical, endoscopic applications requires a dexterous and compliant mechanism to increase
accessibility and decrease patient injury. However, soft structures do not offer the level of image and platform
stability provided by rigid structures. Thus, a variable stiffness mechanism is an ideal solution to reconcile the
two requirements of compliance and stability; the mechanism explored here is granular jamming. Granular
jamming is a phenomenon in which particulate matter within a membrane can transition from a fluidlike to a
solidlike state, based on the level of applied vacuum pressure. In the solidlike jammed state, the conventional
assumption is made that granule–granule contacts dominantly contribute to the system’s stiffness. Thus, many
works have evaluated the effects of different granule types by experimentally varying the sizes, shapes, and
material properties of the particles. However, the role of the membrane in determining the possible range of
stiffness or the variability of granular jamming has not been well studied. This article investigates the effects
and significance of membranes for a granular jamming system. Several membranes were experimentally tested
and analyzed in order to find the amount of flexibility and stiffness they provide when the system is in an
unjammed and jammed state, respectively. This article presents for the first time that the membrane plays a
significant contributing factor in granular jamming stiffness.
Evaluation of the emergency department patient with acute abdominal pain is sometimes difficult. Various factors can obscure the presentation, delaying or preventing the correct diagnosis, with subsequent adverse patient outcomes. Clinicians must consider multiple diagnoses, especially those life-threatening conditions that require timely intervention to limit morbidity and mortality. This article will review general information on abdominal pain and discuss the clinical approach by review of the history and the physical examination. Additionally, this article will discuss the approach to unstable patients with abdominal pain.
Physical examination (PEx) skills are declining among medical trainees, yet many institutions are not teaching these systematically and effectively. Many variables contribute to effective teaching: teachers' confidence in their clinical skills, ability to demonstrate and assess these skills; availability of suitable patients; trainee attitude and fatigue; belief that institutions do not value clinical teachers. Finally, the relevance and significance of a systematic exam must be demonstrated or the teaching degenerates into a 'show-and-tell' exercise.
This paper describes twelve practical teaching tips that can be used to promote high quality PEx teaching in 5 minutes or 45 minutes. TEACHING TIPS: (1) Diagnostic hypotheses should guide reflective exam; (2) Teachers with the best clinical skills should be recruited; (3) A longitudinal and systematic curriculum can tailor teaching to multiple learner levels (4) Integration of simulation and bedside teaching can maximise learning; (5) Bedside detective work and games make learning fun; (6) The 6-step approach to teach procedures can be adopted to teach PEx; (7) Clinical teaching at the bedside should be increased; (8) Linking basic sciences to clinical findings will demonstrate relevance; (9) Since assessment drives learning, clinical skills should be systematically assessed; (10) Staff development can target improvement of teachers' clinical skills for effective teaching; (11) Technology should be used to study utility of clinical signs; (12) Institutions should elevate the importance of clinical skills teaching and recognize and reward teachers.
PEx is important in patient-physician interactions, a valuable contributor to accurate clinical diagnosis and can be taught effectively using practical tips. To reverse the trend of deficient clinical skills, precision of clinical findings should be studied and exam manoeuvres that do not contribute to diagnosis discarded; institutions should value clinical skills teaching, appoint and fund core faculty to teach and provide staff development to improve teaching skills.
Physicians use pain expressions shown in a patient's face to regulate their palpation methods during physical examination. Training to interpret patients' facial expressions with different genders and ethnicities still remains a challenge, taking novices a long time to learn through experience. This paper presents MorphFace: a controllable 3D physical-virtual hybrid face to represent pain expressions of patients from different ethnicity-gender backgrounds. It is also an intermediate step to expose trainee physicians to the gender and ethnic diversity of patients. We extracted four principal components from the Chicago Face Database to design a four degrees of freedom (DoF) physical face controlled via tendons to span ~85% of facial variations among gender and ethnicity. Details such as skin colour, skin texture, and facial expressions are synthesized by a virtual model and projected onto the 3D physical face via a front-mounted LED projector to obtain a hybrid controllable patient face simulator. A user study revealed that certain differences in ethnicity between the observer and the MorphFace lead to different perceived pain intensity for the same pain level rendered by the MorphFace. This highlights the value of having MorphFace as a controllable hybrid simulator to quantify perceptual differences during physician training.
Robotic phantoms enable advanced physical examination training before using human patients. In this article, we present an abdominal phantom for palpation training with controllable stiffness liver nodules that can also sense palpation forces. The coupled sensing and actuation approach is achieved by pneumatic control of positive-granular jammed nodules for tunable stiffness. Soft sensing is done using the variation of internal pressure of the nodules under external forces. This article makes original contributions to extend the linear region of the neo-Hookean characteristic of the mechanical behavior of the nodules by 140% compared to no-jamming conditions and to propose a method using the organ level controllable nodules as sensors to estimate palpation position and force with a root-mean-square error of 4% and 6.5%, respectively. Compared to conventional soft sensors, the method allows the phantom to sense with no interference to the simulated physiological conditions when providing quantified feedback to trainees, and to enable training following current bare-hand examination protocols without the need to wear data gloves to collect data.
Haptic shape displays provide compelling touch interactions by allowing users to freely explore a rendered surface. However, these displays are currently limited to 2.5-D surfaces due to the space requirements of their actuation. Building on previous work in haptic jamming, we developed a novel, soft 3-D shape display. A fully 3-D display that a user can grasp and hold allows for improved interactions for applications such as medical palpation training and virtual reality experiences. The shape display is implemented as an inflatable silicone membrane with embedded particle jamming cells that change stiffness and soft pneumatic actuators that control the distance between points on the surface. The device was modeled as a mass-spring system, and this model is used to develop a control sequence for a device to match a target shape. Due to constraints in actuation imposed by the 3-D geometry of the device, we developed an automatic design algorithm for the display, so that a display can be custom-designed to reach a set of target shapes using a relatively small number of actuators.
Variable stiffness continuum structures of large diameters are suitable for high-capability robots, such as in industrial practices where high loads and human–robot interaction are expected. Existing variable stiffness technologies have focused on application as medical manipulators, and as such have been limited to small diameter designs (
15 mm). Various performance metrics have been presented for continuum structures thus far, focusing on force resistance, but no universal testing methodology for continuum structures that encapsulates their overall performance has been provided. This letter presents five individual qualities that can be experimentally quantified to establish the overall performance capability of a design with respect to its use as a variable stiffness continuum manipulator. Six large diameter (
40 mm) continuum structures are developed following both conventional (granular and layer jamming) and novel (hybrid designs and structurally supported layer jamming) approaches and are compared using the presented testing methodology. The development of the continuum structures is discussed, and a detailed insight into the tested quality selection and experimental methodology is presented. Results of experiments demonstrate the suitability of the proposed approach for assessing variable stiffness continuum capability across the design.
Medical manikins play an essential role in the training process of physicians. Currently, most available simu-lators for abdominal palpation training do not contain control-lable organs for dynamic simulations. In this paper, we present a soft robotics controllable liver that can simulate various liver diseases and symptoms for effective and realistic palpation training. The tumors in the liver model are designed based on granular jamming with positive pressure, which converts the fluid-like impalpable particles to a solid-like tumor state by applying low positive pressure on the membrane. Through inflation, the tumor size, liver stiffness, and liver size can be controlled from normal liver state to various abnormalities including enlarged liver, cirrhotic liver, and multiple cancerous and malignant tumors. Mechanical tests have been conducted in the study to evaluate the liver design and the role of positive pressure granular jamming in tumor simulations.
Palpation exam is a procedure in which a healthcare professional presses a specific region of a patient's body with the fingers in order to detect the presence of features and abnormalities under the skin. A simulator that AIDS the training of this procedure may contribute to the learning of the technique and the improvement of its implementation in real patients. This article presents a systematic review conducted in order to assess the state of the art of the simulation of the palpation procedure, providing a categorization of techniques and approaches used in systems with haptic feedback. The results indicate that there are existing gaps concerning the accessibility of the haptic devices, innovative methods to calculate force feedback and deformation caused by haptic devices, and user experience improvement, since most of the studies consider only one point of contact, which can limit the simulation realism.
The need for building robots with soft materials emerged recently from considerations of the limitations of service robots in negotiating natural environments, from observation of the role of compliance in animals and plants , and even from the role attributed to the physical body in movement control and intelligence, in the so-called embodied intelligence or morphological computation paradigm -. The wide spread of soft robotics relies on numerous investigations of diverse materials and technologies for actuation and sensing, and on research of control techniques, all of which can serve the purpose of building robots with high deformability and compliance. But the core challenge of soft robotics research is, in fact, the variability and controllability of such deformability and compliance.
Jamming--the mechanism by which granular media can transition between liquid-like and solid-like states-has recently been demonstrated as a variable strength and stiffness mechanism in a range of applications. As a low-cost and simple means for achieving tunable mechanical properties, jamming has been used in systems ranging from architectural to medical ones. This thesis explores the utility of jamming for robotic manipulation applications, both at a fundamental level of understanding how granular properties affect the performance of jammed systems, and at a more applied level of designing functional robotic components. Specifically, the purpose of this thesis was to enable engineers to design jammable robotic systems in a principled manner. Three parallel yet related studies were conducted to work towards this goal. First, an experimental analysis was conducted to determine whether the bulk shear strength of granular systems can be correlated with grain properties-such as ones concerning shape, size distribution, and surface texture-extracted from 2D silhouettes of grains. Second, a novel medium composed of a mixture of hard and soft spheres was proposed to achieve variable strength and stiffness properties as a function of confining pressure; experimental analysis was conducted on this system with not only varying confining pressures but also varying mixing ratios of hard and soft spheres. Finally, the design and analysis of a novel jammable robotic manipulator-with the goal of maximizing both the strength and articulation of the system-is presented.
The combination of particle jamming and pneumatics allows the simultaneous control of shape and mechanical properties in a tactile display. A hollow silicone membrane is molded into an array of thin cells, each filled with coffee grounds such that adjusting the vacuum level in any individual cell rapidly switches it between flexible and rigid states. The array clamps over a pressure-regulated air chamber with internal mechanisms designed to pin the nodes between cells at any given height. Various sequences of cell vacuuming, node pinning, and chamber pressurization allow the surface to balloon into a variety of shapes. Experiments were performed to expand existing physical models of jamming at the inter-particle level to define the rheological characteristics of jammed systems from a macroscopic perspective, relevant to force-displacement interactions that would be experienced by human users. Force-displacement data show that a jammed cell in compression fits a Maxwell model and a cell deflected in the center while supported only at the edges fits a Zener model, each with stiffness and damping parameters that increase at higher levels of applied vacuum. This provides framework to tune and control the mechanical properties of a jamming.
While it is known that softness discrimination relies on both kinesthetic and cutaneous information, relatively little work has been done on the realization of haptic devices replicating the two cues in an integrated and effective way. In this paper, we first discuss the ambiguities that arise in unimodal touch, and provide a simple intuitive explanation in terms of basic contact mechanics. With this as a motivation, we discuss the implementation and control of an integrated device, where a conventional kinesthetic haptic display is combined with a cutaneous softness display. We investigate the effectiveness of the integrated display via a number of psychophysical tests and compare the subjective perception of softness with that obtained by direct touch on physical objects. Results show that the subjects interacting with the integrated haptic display are able to discriminate softness better than with either a purely kinesthetic or a purely cutaneous display.
This review paper discusses the role of haptics within virtual medical training applications, particularly, where it can be used to aid a practitioner to learn and practice a task. The review summarizes aspects to be considered in the deployment of haptics technologies in medical training. First, both force/torque and tactile feedback hardware solutions that are currently produced commercially and in academia are reviewed, followed by the available haptics-related software and then an in-depth analysis of medical training simulations that include haptic feedback. The review is summarized with scrutiny of emerging technologies and discusses future directions in the field.
Inspection consists of visual examination of the abdomen with note made of the shape of the abdomen, skin abnormalities, abdominal masses, and the movement of the abdominal wall with respiration. Abnormalities detected on inspection provide clues to intra-abdominal pathology; these are further investigated with auscultation and palpation. Auscultation of the abdomen is performed for detection of altered bowel sounds, rubs, or vascular bruits. Normal peristalsis creates bowel sounds that may be altered or absent by disease. Irritation of serosal surfaces may produce a sound (rub) as an organ moves against the serosal surface. Atherosclerosis may alter arterial blood flow so that a bruit is produced. Palpation is the examination of the abdomen for crepitus of the abdominal wall, for any abdominal tenderness, or for abdominal masses. The liver and kidneys may be palpable in normal individuals, but any other masses are abnormal.
Palpation is a widely used diagnostic method in medical practice. The sensitivity of palpation is highly dependent upon the skill of clinicians, which is often difficult to master. There is a need of simulators in palpation training. This paper summarizes important work and the latest achievements in simulation for palpation training. Three types of simulators; physical models, Virtual Reality (VR) based simulations, and hybrid (computerized and physical) simulators, are surveyed. Comparisons among different kinds of simulators are presented.
The need for a simply applied quantitative assessment of handedness is discussed and some previous forms reviewed. An inventory of 20 items with a set of instructions and response- and computational-conventions is proposed and the results obtained from a young adult population numbering some 1100 individuals are reported. The separate items are examined from the point of view of sex, cultural and socio-economic factors which might appertain to them and also of their inter-relationship to each other and to the measure computed from them all. Criteria derived from these considerations are then applied to eliminate 10 of the original 20 items and the results recomputed to provide frequency-distribution and cumulative frequency functions and a revised item-analysis. The difference of incidence of handedness between the sexes is discussed.
For part I see ibid., p.263-70 (1994). The existing touch display
technologies in the literature are surveyed. This survey indicates five
main approaches to touch feedback, involving visual, pneumatic,
vibro-tactile, electro-tactile and neuromuscular stimulations. A
pneumatics approach could use air jets, air pockets or inflatable
bladders to provide touch feedback cues to the operator. Similarly the
vibro-tactile approach could use vibrating pins, voice coils, or
piezoelectric crystals to provide tickling sensation to the human
operator's skin to signal the touch. The electro-tactile stimulation
method can provide electric pulses of appropriate width and frequency to
the skin, while the neuromuscular stimulation approach provides the
signals directly to the primary cortex of the operator's brain. With
regard to this, 17 devices, most of which were built for sensory
substitution purposes, are examined and compared for their suitability
as touch feedback devices for dexterous telemanipulation
Bates' guide to physical examination and history-taking
L. Bickley and P. Szilagyi, Bates' guide to physical examination and
history-taking, 12th ed. Philadelphia : Wolters Kluwer, 2012, vol. 13.
Clinical Methods: The History, Physical and Laboratory Examinations
C M Ferguson
C. M. Ferguson, "Inspection, auscultation, palpation, and percussion
of the abdomen," Clinical Methods: The History, Physical and Laboratory Examinations. 3rd edn. Boston, MA: Butterworths, 1990.