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PubMed2006

Estimating 3D joint kinematics from video sequences of running and cutting maneuvers--assessing the accuracy of simple visual inspection.

Videos of sports injuries can potentially provide valuable information on non-contact ACL injuries. However, only the un-validated simple visual inspection approach has, so far, been used. Therefore, the purpose of this study was to test the accuracy and precision of researchers in estimating kinematics from video sequences of situations that typically lead to ACL injuries. We also tested if accuracy and precision could be improved through a training program. Using a routine surface marker based infrared, 240 Hz, 3D motion analysis system, we recorded running and cutting trials from three test subjects. Six observers were asked to provide estimates of kinematic variables from 27 video composites from one, two or three ordinary cameras, systematically varying viewing angles and time point of analysis. The observers thereafter went through a training program where 35 similar composites were analyzed, and feedback on the kinematics, as measured by the 3D motion analysis system, was provided on a group basis. Finally, the test was repeated to assess accuracy and precision. The mean error for knee flexion was -19 degrees, indicating a consistent underestimation. Hip flexion was underestimated by 7 degrees, but the standard deviation between the observers was 18 degrees on average, indicating poor consistency. Substantial errors were also found in the accuracy and precision of the other estimates. Only small group effects were seen from our training program. Based on these findings, results from studies using a simple visual inspection approach to describe joint motion must be interpreted with caution.

Adult↗

PubMed1996

Interactions between endothelin-1 and atrial natriuretic peptide influence cultured chick cardiac myocyte contractility.

We have previously shown that rat atrial natriuretic peptide (ANP) reduces the contractility of cultured, spontaneously beating chick embryo ventricular cells, an effect opposite to that of endothelin-1. Endothelin-1 has been described as a secretagogue for natriuretic peptides in vitro and in vivo. Natriuretic peptides can inhibit endothelin-1 secretion from cultured endothelial cells, suggesting a negative feedback mechanism between endothelial cells and cardiomyocytes. The aim of this study was to determine whether ANP attenuated the endothelin-1-induced increase in myocyte contractility. Using a video-microscopy system we studied the contractility of isolated cultured chick ventricular myocytes in response to endothelin-1, chicken natriuretic peptide (ChNP), and both. We also used Northern blot analysis to study the time course of ChNP expression in response to endothelin-1. Endothelin-1 (10(-8) M) increased chick cardiomyocyte contractility by 20-25% between 5 and 15 min (P < 0.05). Although ChNP (3 x 10(-7) M) did not significantly change the amplitude of contraction in basal conditions, it prevented the endothelin-1-induced increase in contractility (P < 0.05) when perfused prior to endothelin-1, and reversed it when perfused 5 min after endothelin-1 exposure (P < 0.05). Endothelin-1 significantly increased the accumulation of ChNP mRNA in chick ventricular myocytes as early as the 30 min after exposure (P < 0.05), with a maximal effect after 2 h of stimulation (P < 0.01); no effect was observed after 4 h. These data support an interaction between endothelin-1 and natriuretic peptides as autocrine/paracrine factors regulating the contractile function of chick cardiac myocytes, as well as their antagonistic effects on cardiac cell contractility. The early and transient expression of ChNP mRNA in response to endothelin-1 may be involved in this interaction.

Analysis of Variance↗

PubMed1989

Hemispheric consequences of success-related emotional states: roles of arousal and attention.

Three experiments employed a video game technique to investigate the influence of success-related emotional states on the detection of lateralized visual targets. Emotion was manipulated by means of success and failure feedback, while central and peripheral pretarget cues were used to assess arousal and attentional processes. Under neutral conditions involving no feedback, subjects showed a right visual field (RVF) advantage along with a phasic alerting effect (i.e., reaction times were faster to targets following cues at intermediate stimulus onset asynchronies (SOAs]. When emotional value was added to the task, the RVF advantage increased following failure and decreased following success feedback. This effect peaked at intermediate SOAs, corresponding with the buildup of phasic arousal initiated by the cues. It was not influenced by the location of the pretarget cues, suggesting that attentional processes are not directly involved. These results are discussed in terms of recent models of hemispheric functioning during positive and negative emotional states.

Achievement↗

PubMed2006

Teaching surgical decision-making: an interactive, web-based approach.

BACKGROUND: Skillful surgical care demands proper patient assessment and decision-making. These skills are honed through long hours and years of clinical practice. A decrease in work hours is reducing the number of cases managed by medical students and residents. We have developed a set of interactive, web-based teaching modules to help fill this gap. MATERIALS AND METHODS: The modules aim to teach surgical decision-making in a convenient, nonthreatening manner. Surgical case material is presented in a graphically rich environment, including video and sound to enhance realism. At the end of each web-page, the user must make a management decision. The correct answer is subsequently provided with immediate feedback. Medical students used and evaluated the modules during their surgical clerkships. Additionally, students took a pretest and 1-week delayed posttest after completing the modules to assess the program's efficacy. RESULTS: Eight modules involving pediatric and general surgery have been completed. Medical students gave high ratings to the quality of the modules and found the interactive format both engaging and educationally effective. Eighty-seven percent of medical students rated the program's educational value as above average to excellent. On pre- and posttest analysis, students' scores improved an average of 24.8% (P < 0.001). CONCLUSION: Students enjoy web-based educational material. Additional modules covering a range of surgical topics are in development. Web-based modules appear to be an effective clinical teaching tool, well-suited for integration into the clinical curriculum.

Computer-Assisted Instruction↗

PubMed1998

Learning voice analysis using an interactive multi-media package: development and preliminary evaluation.

An important outcome of education for speech-language pathology practice is the ability to analyze voices perceptually, a complex task that is often difficult for novices. This article describes an interactive multi-media package, "A Sound Judgement," that is designed to help students develop skills in perceptual voice analysis and to link their perceptions to laryngeal physiology. The package presents a range of clients with vocal impairments at increasing levels of complexity. Each case has a videoed interview, endoscopic views and animations of the larynx, and case history information. Students make perceptual ratings of clients' voices on a format designed specifically for this package and feedback is provided using ratings made by expert speech-language pathologists. High levels of consensus for the perceptual judgments were achieved among the expert raters. Preliminary evaluations by students have demonstrated that "A Sound Judgement" is likely to be a valuable educational tool.

Computer-Assisted Instruction↗

PubMed2002

WebCT: integrating computer-mediated communication and resource delivery into a new problem-based curriculum.

WebCT, front-end software for Internet-delivered material, became an integral part of a problem-based learning, student-centred curriculum introduced in January 2001 at the Nelson R. Mandela School of Medicine (South Africa). A template for six curriculum and two supplementary modules was developed. Organiser and Tool pages were added and files uploaded as each module progressed. This study provides feedback from students with regard to the value of WebCT in their curriculum, as well as discussing the value of WebCT for the delivery of digitized material (e.g., images, videos, PowerPoint presentations). In an anonymous survey following the completion of the first module, students, apparently irrespective of their level of computer literacy, responded positively to the communication facility between staff and students and amongst students, the resources and the URLs. Based on these preliminary responses, WebCT courses for all six modules were developed during 2001. With Faculty support, WebCT will probably be integrated into the rest of the MBChB programme. It will be particularly useful when students are off campus, undertaking electives and community service in the later years.

Computer-Assisted Instruction↗

PubMed2002

Virtual reality surgical simulation for lower urinary tract endoscopy and procedures.

BACKGROUND AND PURPOSE: To provide a realistic experience of lower urinary tract endoscopic procedures, we have developed and continue to expand a computer-based surgical simulator that incorporates a surgical tool interface with anatomic detail and haptic feedback. METHODS: Surface-based geometric data for the lower urinary tract were generated from the National Library of Medicine Visible Human dataset. The three-dimensional texture map of the surface geometry was developed from recorded endoscopic video procedures. Geometry and associated texture maps were rendered in real time using the Silicon Graphics Extreme Impacts program. The surgical interface device incorporated all normal ranges of motion and resistance that occur within an actual operative environment. The hands-on endoscopic device attached to the interface device was provided by Circon-ACMI, Inc. Urologic residents evaluated the program for correlation with actual endoscopic procedures. RESULTS: Texture-mapped digitized images provided a close anatomic similarity to actual videoendoscopic images. Virtual endoscopy of the lower urinary tract was reproducible and closely simulated actual visual and tactile endoscopic experience. CONCLUSIONS: Virtual reality surgical simulation is feasible for a variety of lower urinary tract procedures. This system coordinates visual perception with appropriate haptic feedback in both longitudinal and rotational axes. These types of procedures may be incorporated into future educational experiences for urologists to introduce new techniques and to provide documentation of surgical experience.

Adult↗

PubMed2005

Intraoperative sentinel lymph node mapping of the lung using near-infrared fluorescent quantum dots.

BACKGROUND: The presence of lymph node metastases is an important prognostic marker with regard to non-small-cell lung cancer (NSCLC). Assessment of the sentinel lymph node (SLN) for the presence of tumor may improve staging. Our objective was to develop an optical noninvasive imaging tool that would permit intraoperative SLN mapping and provide real-time visual feedback for image-guided localization and resection. METHODS: Invisible near-infrared (NIR) light penetrates relatively deeply into tissue and background autofluorescence is low. We have developed a NIR fluorescence imaging system that simultaneously displays color video and NIR images of the surgical field. We recently engineered 15 nm nonradioactive NIR fluorescent quantum dots (QDs) as optimal lymphotrophic optical probes. The introduction of these QDs into lung tissue allows real-time visualization of draining lymphatic channels and nodes. RESULTS: In 12 Yorkshire pigs (mean weight 35 kg) we demonstrated that 200 pmol of NIR QDs injected into lobar parenchyma accurately maps lymphatic drainage and the SLN. All SLNs were strongly fluorescent and easily visualized within 5 minutes of injection. In 14 separate injections QDs localized to a mediastinal node, whereas in 2 injections QDs localized to a hilar intraparenchymal node. Histologic analysis in all cases confirmed the presence of nodal tissue. CONCLUSIONS: We report a highly sensitive rapid technique for SLN mapping of the lung. This technique permits precise real-time imaging and therefore overcomes many limitations of currently available techniques.

Animals↗

PubMed2004

A breed apart.

Explore the source record for details and available documents.

Altitude↗

PubMed2000

The development of "Nutrition in Medicine" interactive CD-ROM programs for medical nutrition education.

In 1995 and in 1998 the University of North Carolina at Chapel Hill received R25 grant support to create interactive CD-ROMs for teaching nutrition and nutritional biochemistry to medical students, the Nutrition In Medicine (NIM) series. Seven of the proposed ten titles have been created. Three series (Disease, Lifecycle, and Special Topics in Nutrition) teach nutrition concepts using computer-aided instruction (CAI) with emphasis on interactive learning. Patient cases with television-quality interactive videos allow students to apply nutrition knowledge to clinical problems. Pop quizzes, text-based interactions, and multiple-choice examinations help the student self-evaluate progress via immediate feedback. Educators using the programs get instructional support and updates through a dedicated Web site, printed material, telephone support, e-mail, and CD-ROM-based computer programs. Implementation at medical and osteopathic schools is continuously surveyed through questionnaires and follow-up telephone interviews. By 1999, 120 of 137 eligible U.S. medical schools owned copies of NIM CAI programs, of which 76 indicated that they were currently implementing the programs.

CD-ROM↗

PubMed2005

"Binkie flutter," an apparently voluntary behavior of infants, possibly related to vibratory jaw movements in dogs: report of 4 cases.

Four cases of apparently voluntary rapid vibratory pacifier movements occurring in normal, unstressed infants up to 1 year of age and captured on video are presented. I speculate on the possible relationship of the movements to similar vibratory jaw movements in dogs, in which species they may represent a neuromuscular mechanism for rapid feedback control.

Female↗

PubMed2002

A haptic virtual environment for tele-echography.

Having a haptic virtual environment for tele-echography will enable the medical expert with faster adaptation and especially facilitated immersion in what we could call a "virtual echographic examination cabinet". The innovation of this haptic control is to preserve medical expert proprioception and gesture feelings, which provide the users with indications that are synchronized with the echographic images. In this paper, we will focus on the telegesture module: we will detail several issues and solutions related to this particular problem of tele-robotic scan examination.

Communication↗

PubMed1996

Tensile behaviour of fibroblasts cultured in collagen gel.

An in vitro morphological study on the relation of the stress field and the orientation of cells with the use of the time lapse video recording system was carried out. Specimens of thin collagen gel membrane, within which cells are proliferating, were examined under various mechanical conditions. Cell stretching, cell orientation, cell migration, cell proliferation and generation of tensile stress in collagen gel were recorded. It was demonstrated that fibroblasts generate tension and change their orientation along the tensile direction. A hypothetical mechanism for such phenomena is proposed, that is, fibroblasts generate tension and make tense collagen fibres, then cells stretch themselves along the tense fibres and increase tension in this direction. Thus, this mechanism works as a positive feedback loop which enables cells to make tensile stresses and align along them in accordance with the mechanical environment.

Animals↗

PubMed2002

CT, MRI and video based analysis of knee kinematics--a basis for CT based simulation.

With the new computer aided surgery techniques a surgery can be split in two phases, which are pre-operative planning and intervention. The planning is frequently based on three dimensional image data and takes place in the office of the surgeon. Using this approach the surgical feeling, the physical feedback of the patient, is not available during the planning phase. However, this feedback yields information, which is helpful or necessary for the planning. This lack of information can be compensated by a simulation module, which simulates kinematic data from image volume data. To develop such a module first both image volume data and kinematic data have to be captured from a wide range of patients. In this work a new approach for kinematic analysis of the knee is presented which yields an accuracy which is necessary for such simulation. Because the analysis has to be done for many patients the degree of invasiveness is emphasized. This contactless and non invasive approach is based on external fixations, anatomical skin markers, video sequences and computer tomograms. Position tracking of femur and tibia for any motion pattern is possible. Because the individual anatomic structures extracted from the tomogram are tracked, an analysis of any point or coordinate system can be done later using the originally captured data. This gives a new degree of freedom for analysis.

Biomechanical Phenomena↗

PubMed2005

Effect of gazing at the camera during a video link on recall.

The impact of looking into the camera during a presentation over a video link (resulting in the perception of mutual gaze) on information recall was investigated. In a face-to-face context mutual gaze has been shown to facilitate the encoding and subsequent recall of information [Fry, R., Smith, G.F., 1975. The effects of feedback and eye contact on performance of a digit-coding task. J. Soc. Psychol. 96, 145-146; Otteson, J.D., Otteson, C.R., 1980. Effect of teacher's gaze on children's story recall. Percept. Motor Skill. 50, 35-42; Sherwood, J.V., 1988. Facilitative effects of gaze upon learning. Percept. Motor Skill. 64 (3 Part 2), 1275-1278]. One explanation for these findings is that gaze acts as an arousal stimulus, which increases attentional focus and therefore enhances memory [Kelley, D.H., Gorham, J., 1988. Effects of immediacy on recall of information. Commun. Edu. 37(3), 198-207]. Two studies were conducted in order to test whether gazing at the camera during video-mediated presentations resulted in similar benefits as mutual gaze in a face-to-face context. In study 1 a confederate presented information about two fictitious soap products. In one condition, the confederate gazed at the camera for 30% of the presentation, therefore giving the participants the impression that he was gazing in their direction. In the other condition the confederate did not gaze at the camera. Participants viewed the sales presentations from both conditions. In the condition where gaze was directed at the camera, participants recalled significantly more information about the sales presentation. Study 2 employed the same pre-recorded sales presentations used in study 1, however they were delivered to the participants under audio-only conditions (therefore, the image was switched off). Results from study 2 indicated no recall differences between the two conditions. Findings from these studies would seem to indicate that the perception of gaze aversion over a video link (a consequence of the salesman not looking into the camera) has a negative impact on information recall. This has practical implications for video-mediated presentations. In a distance learning environment lecturers could be advised to look into the camera in order to promote more efficient learning in students.

Adult↗

PubMed2005

Optimisation Issues of High Throughput Medical Data and Video Streaming Traffic in 3G Wireless Environments.

In this paper we describe some of the optimisation issues relevant to the requirements of high throughput of medical data and video streaming traffic in 3G wireless environments. In particular we present a challenging 3G mobile health care application that requires a demanding 3G medical data throughput. We also describe the 3G QoS requirement of mObile Tele-Echography ultra-Light rObot system (OTELO that is designed to provide seamless 3G connectivity for real-time ultrasound medical video streams and diagnosis from a remote site (robotic and patient station) manipulated by an expert side (specialists) that is controlling the robotic scanning operation and presenting a real-time feedback diagnosis using 3G wireless communication links.

Humans↗

PubMed2005

Automated extraction of temporal motor activity signals from video recordings of neonatal seizures based on adaptive block matching.

This paper presents an automated procedure developed to extract quantitative information from video recordings of neonatal seizures in the form of motor activity signals. This procedure relies on optical flow computation to select anatomical sites located on the infants' body parts. Motor activity signals are extracted by tracking selected anatomical sites during the seizure using adaptive block matching. A block of pixels is tracked throughout a sequence of frames by searching for the most similar block of pixels in subsequent frames; this search is facilitated by employing various update strategies to account for the changing appearance of the block. The proposed procedure is used to extract temporal motor activity signals from video recordings of neonatal seizures and other events not associated with seizures.

Algorithms↗

PubMed2006

Effective hand hygiene education with the use of flipcharts in a hospital in El Salvador.

In developing countries, continuing education for healthcare staff may be limited by staff shortages and lack of sophisticated means of delivery. These limitations have implications for compliance with an important infection control practice, namely good hand hygiene. A comparison was made between the efficacy of two educational tools commonly used in healthcare and practical sanitation settings in developing countries, i.e. videotapes and flipcharts, in delivering hand hygiene education to 67 nurses in a paediatric hospital in El Salvador. Efficacy was measured on the basis of scores obtained in pre- and post-training tests consisting of 10 multiple-choice questions. Half of the nurses received video-based instruction and half received instruction via flipcharts. Both methods of instruction increased participants' knowledge of good hand hygiene, and the extent of knowledge acquisition by the two methods was similar. Feedback obtained from flipchart users six months after training indicated that most of the respondents used the flipchart to teach hand hygiene to patients' families (62.5%), patients (50%) and healthcare workers (43.8%). Flipchart users ranked flipcharts as their favourite educational tool. Flipcharts offer an economical, easy-to-use, non-technological yet effective alternative to videotapes for delivering education in developing countries. Although the use of flipcharts requires a skilled and well-trained instructor, flipcharts could be used more widely to deliver education in resource-poor settings.

Audiovisual Aids↗