SEARCH · PubMed Health

Results for “Video feedback”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources

PubMed2000

Learning about the dynamic swallowing process using an interactive multimedia program.

The management of dysphagia is the largest recognized subspecialty in the field of speech-language pathology. Practicing speech-language pathologists require a comprehensive theoretical and functional knowledge base to underpin the safe and effective management of people with dysphagia. Students need to develop an understanding of the normal integrated swallow and how it can be affected to appreciate the assessment or treatment of dysphagia. Although students are well motivated to learn this material, assimilating knowledge of the dynamic nature of the swallow has typically been problematic because of its complex character. The limitations of currently available teaching resources have been addressed by the production of an interactive multimedia program that includes integrated presentation of text, graphics, voice-overs, and video and animation sequences to highlight various aspects of the swallowing process. Students can selectively manipulate parts of this process to understand the normal swallow and to simulate different aspects of dysfunction and the consequent effects on swallow safety and efficiency. Feedback from students, faculty, and experts has demonstrated that The Dynamic Swallow would be a valued tool in the teaching of dysphagia.

CD-ROM↗

PubMed2006

High-level virtual reality simulator for endourologic procedures of lower urinary tract.

OBJECTIVES: To analyze the limitations of existing simulators for urologic techniques, and then test and evaluate a novel virtual reality (VR) simulator for endourologic procedures of the lower urinary tract. Surgical simulation using VR has the potential to have a tremendous impact on surgical training, testing, and certification. Endourologic procedures seem to be an ideal target for VR systems. METHODS: The URO-Trainer features genuine VR, obtained from digital video footage of more than 400 endourologic diagnostic and therapeutic procedures, as well as data from cross-sectional imaging. The software offers infinite random variations of the anatomy and pathologic features for diagnosis and surgical intervention. An advanced haptic force feedback is incorporated. Virtual cystoscopy and resection of bladder tumors were evaluated by 24 medical students and 12 residents at our department. RESULTS: The system was assessed by more than 150 international urologists with varying experience at different conventions and workshops from March 2003 to September 2004. Because of these evaluations and constant evolutions, the final version provides a genuine representation of endourologic procedures. Objective data are generated by a tutoring system that has documented evident teaching benefits for medical students and residents in cystoscopy and treatment of bladder tumors. CONCLUSIONS: The URO-Trainer represents the latest generation of endoscopy simulators. Authentic visual and haptic sensations, unlimited virtual cases, and an intelligent tutoring system make this modular system an important improvement in computer-based training and quality control in urology.

Computer Simulation↗

PubMed2001

Performance-driven facial animation: basic research on human judgments of emotional state in facial avatars.

Virtual reality is rapidly evolving into a pragmatically usable technology for mental health (MH) applications. As the underlying enabling technologies continue to evolve and allow us to design more useful and usable structural virtual environments (VEs), the next important challenge will involve populating these environments with virtual representations of humans (avatars). This will be vital to create mental health VEs that leverage the use of avatars for applications that require human-human interaction and communication. As Alessi et al.1 pointed out at the 8th Annual Medicine Meets Virtual Reality Conference (MMVR8), virtual humans have mainly appeared in MH applications to "serve the role of props, rather than humans." More believable avatars inhabiting VEs would open up possibilities for MH applications that address social interaction, communication, instruction, assessment, and rehabilitation issues. They could also serve to enhance realism that might in turn promote the experience of presence in VR. Additionally, it will soon be possible to use computer-generated avatars that serve to provide believable dynamic facial and bodily representations of individuals communicating from a distance in real time. This could support the delivery, in shared virtual environments, of more natural human interaction styles, similar to what is used in real life between people. These techniques could enhance communication and interaction by leveraging our natural sensing and perceiving capabilities and offer the potential to model human-computer-human interaction after human-human interaction. To enhance the authenticity of virtual human representations, advances in the rendering of facial and gestural behaviors that support implicit communication will be needed. In this regard, the current paper presents data from a study that compared human raters' judgments of emotional expression between actual video clips of facial expressions and identical expressions rendered on a three-dimensional avatar using a performance-driven facial animation (PDFA) system developed at the University of Southern California Integrated Media Systems Center. PDFA offers a means for creating high-fidelity visual representations of human faces and bodies. This effort explores the feasibility of sensing and reproducing a range of facial expressions with a PDFA system. In order to test concordance of human ratings of emotional expression between video and avatar facial delivery, we first had facial model subjects observe stimuli that were designed to elicit naturalistic facial expressions. The emotional stimulus induction involved presenting text-based, still image, and video clips to subjects that were previously rated to induce facial expressions for the six universals2 of facial expression (happy, sad, fear, anger, disgust, and surprise), in addition to attentiveness, puzzlement and frustration. Videotapes of these induced facial expressions that best represented prototypic examples of the above emotional states and three-dimensional avatar animations of the same facial expressions were randomly presented to 38 human raters. The raters used open-end, forced choice and seven-point Likert-type scales to rate expression in terms of identification. The forced choice and seven-point ratings provided the most usable data to determine video/animation concordance and these data are presented. To support a clear understanding of this data, a website has been set up that will allow readers to view the video and facial animation clips to illustrate the assets and limitations of these types of facial expression-rendering methods (www. USCAvatars.com/MMVR). This methodological first step in our research program has served to provide valuable human user-centered feedback to support the iterative design and development of facial avatar characteristics for expression of emotional communication.

Adolescent↗

PubMed1995

A brief office-based intervention to facilitate diabetes dietary self-management.

There is a pressing need for brief, practical interventions that address diabetes management. We have developed an office-based intervention to prompt both patients and providers to focus on behavioral issues relevant to dietary self-management that is being evaluated in a randomized trial. The intervention is designed to be broadly applicable to the majority of adult diabetes outpatients during medical visits; uses touchscreen computer assessment to provide immediate feedback on key issues to patients and providers just prior to their interaction; and provides goal setting and problem-solving assistance to patients following their meeting with the physician. Follow-up components include phone calls and videotape or interactive video instruction as needed. The program is described, and demographic and behavioral characteristics of participants are presented for the first 95 patients randomized. Initial process results suggest success in producing modest, targeted behavior changes among a broad cross-section of patients. If the long-term results are equally positive, this intervention could provide a prototype for a feasible, cost-effective way to integrate patient views and behavioral management into office-based care for diabetes.

Adult↗

PubMed1992

Computer-assisted tracking simulation (CATS).

The tracking technique involves a sender reading consecutive segments from a story and a receiver attempting to repeat each segment verbatim. The reliability and validity of the tracking procedure have been criticized based upon uncontrolled variables such as sender, receiver, and text characteristics. To address these problems, a computer-assisted interactive tracking simulation (CATS) system has been developed in which story segments are presented to the receiver via a video laser disc system and repair strategies are implemented through a computer program.

Communication Devices for People with Disabilities↗

PubMed2003

Effect of two different videotaped instructional models on motor and verbal behaviors of adults' lifting: a pilot study.

This study examined two different videotaped instructional models on subsequent motor and verbal behaviors of adults (N=9) learning how to lift properly. The correct model group viewed a narrated videotape of a skilled individual demonstrating lifting; the learning model group viewed a videotape of an unskilled individual being taught lifting by an instructor, and the controls received no intervention. Adults lifted from floor to waist a plastic crate during 15 acquisition and 3 retention trials and lowered the crate from waist to floor during 3 transfer trials. Learning and correct model motor performances were similar yet higher than those of controls during acquisition and transfer trials. Verbal reports indicated learning, and correct models generated more extensive and associated mechanical concepts than controls yet rarely monitored such concepts during performance. A single presentation of videotapes of proper lifting using either correct or learning models is effective in enhancing motor performance and proper lifting knowledge.

Adolescent↗

PubMed2004

The control of memory-guided reaching movements in peripersonal space.

The goal of the present investigation was to explore the putative contributions of feedforward- and feedback-based processes in the control of memory-guided reaching movements. Participants (N = 4) completed an extensive number of reaching movements (2700) to 3 midline targets (20, 30, 40 cm) in 6 visual conditions: full-vision, open-loop, and four memory-guided conditions (0, 200, 400, and 600 ms of delay). To infer limb control, we used a regression technique to examine the within-trial correspondence between the spatial position of the limb at peak acceleration, peak velocity, peak deceleration, and the ultimate movement endpoint. A high degree of within-trial correspondence would suggest that the final position of the limb was largely specified prior to movement onset and not adjusted during the action (i.e., feedforward control); conversely, a low degree of within-trial correspondence would suggest that movements were modified during the reaching trajectory (i.e., feedback control). Full-vision reaches were found to be more accurate and less variable than open-loop and memory-guided reaches. Moreover, full-vision reaches demonstrated only modest within-trial correspondence between the spatial position of the limb at each kinematic marker and the ultimate movement endpoint, suggesting that reaching accuracy was achieved by adjusting the limb trajectory throughout the course of the action. Open-loop and memory-guided movements exhibited strong within-trial correspondence between final limb position and the position of the limb at peak velocity and peak deceleration. This strong correspondence indicates that the final position of the limb was largely determined by processes that occurred before the reach was initiated; errors in the planning process were not corrected during the course of the action. Thus, and contrary to our previous findings in a video-based aiming task, it appears that stored target information is not extensively (if at all) used to modify the trajectory of reaching movements to remembered targets in peripersonal space.

Adult↗

PubMed2000

A virtual-reality-based telerehabilitation system with force feedback.

A PC-based orthopedic rehabilitation system was developed for use at home, while allowing remote monitoring from the clinic. The home rehabilitation station has a Pentium II PC with graphics accelerator, a Polhemus tracker, and a multipurpose haptic control interface. This novel interface is used to sample a patient's hand positions and to provide resistive forces using the Rutgers Master II (RMII) glove. A library of virtual rehabilitation routines was developed using WorldToolKit software. At the present time, it consists of three physical therapy exercises (DigiKey, ball, and power putty) and two functional rehabilitation exercises (peg board and ball game). These virtual reality exercises allow automatic and transparent patient data collection into an Oracle database. A remote Pentium II PC is connected with the home-based PC over the Internet and an additional video conferencing connection. The remote computer is running an Oracle server to maintain the patient database, monitor progress, and change the exercise level of difficulty. This allows for patient progress monitoring and repeat evaluations over time. The telerehabilitation system is in clinical trails at Stanford Medical School (CA), with progress being monitored from Rutgers University (NJ). Other haptic interfaces currently under development include devices for elbow and knee rehabilitation connected to the same system.

Computer Graphics↗

PubMed2003

A tele-otology course for primary care providers.

The shortage of otolaryngologists and the high incidence of ear disease in remote areas are major problems in Australia. We have developed a multimedia course for primary care providers that incorporates material about ear anatomy and physiology, ear disease, video-otoscopy and telemedicine software. The computer-based course was followed by a practical one-day course. A multiple-choice test was given to participants before and at the end of the course and a form was used to record feedback. The course was conducted with 30 aboriginal health workers. The participants were able to obtain images of reasonable to good quality after a short period of training. There was an average improvement of about 25% in the test scores, and the feedback regarding the course was extremely positive. The CD-ROM and the Website provide a valuable resource to assist primary care providers in their care of patients with ear disorders.

Attitude of Health Personnel↗

PubMed2004

A neurocognitive and socioecological model of self-awareness.

In the past, researchers have focused mainly on the effects and consequences of self-awareness; however, they have neglected a more basic issue pertaining to the specific mechanisms that initiate and sustain self-perception. The author presents a model of self-awareness that proposes the existence of 3 sources of self-information. First, the social milieu includes early face-to-face interactions, self-relevant feedback, a social comparison mechanism that leads to perspective taking, and audiences. Second, contacts with objects and structures in the physical environment foster self-world differentiation in infants; this environment also contains self-focusing and reflecting stimuli, such as mirrors and video cameras. Third, the self can develop bodily awareness through proprioception and can reflect on itself using imagery and inner speech. Furthermore, self-awareness is mainly mediated by the prefrontal lobes. The author establishes various links among these different neurological, social, ecological, and cognitive elements of the model.

Awareness↗

PubMed2004

Bimodal assessment of laparoscopic suturing skills: construct and concurrent validity.

BACKGROUND: The assessment of technical skills should provide objective feedback and judge suitability of progress during training. The aim of this study was to validate two objective assessment techniques for laparoscopic suturing and demonstrate a correlation between them. METHODS: Six experts, seven surgeons skilled in laparoscopic suturing, and 13 with no laparoscopic suturing skills were asked to place two or three intracorporeal sutures on a synthetic suture pad. The latter group was given video-based instructions prior to the execution of the sutures. Ergonomic conditions were standardized for all subjects. The procedures were recorded on videotape and two blinded observers rated the first suture of each subject on a 29-point checklist. A motion analysis system, Imperial College Surgical Assessment Device, was used to assess psychomotor skills. RESULTS: There was a significant difference in the time taken (p = 0.000) and total path length (p = 0.000) per suture across the groups. There were also a significant difference in the total checklist score (p = 0.000) and its individual categories. The was a strong correlation between the total path length and the total checklist score (coefficient, 0.78; p < 0.001). CONCLUSIONS: A combination of the motion analysis system and the checklist would make the process of formative feedback during the learning of intracorporeal suturing objective and comprehensive.

Clinical Competence↗

PubMed2000

Interaction between cell shape and contraction pattern in the Physarum plasmodium.

The relationship between cell shape and rhythmic contractile activity in the large amoeboid organism Physarum polycephalum was studied. The organism develops intricate networks of veins in which protoplasmic sol moved to and fro very regularly. When migrating on plain agar, the plasmodium extends like a sheet and develops dendritic veins toward the rear. After a particular stimulation, the vein organization changes into veinless or vein-network structures. In both structures, the mixing rate of the protoplasm, which is related to communication among contraction oscillators, decreased compared with that of the dendritic one. Accompanying these changes in vein structure, the spatio-temporal pattern of the rhythmic contraction changed into a small-structured pattern from a synchronized one. In the above process, cell shape affects the contraction pattern, but, conversely, the contraction pattern effects the cell shape. To demonstrate this, a phase difference in the rhythmic contraction was induced artificially by entraining the intrinsic rhythm to external temperature oscillations. New veins then formed along the direction parallel to the phase difference of the rhythm. Consequently, the vein organization of the cell interacts with the contractile activity to form a feedback loop in a mechanism of contraction pattern formation.

Animals↗

PubMed1986

Effect of gum hardness on chewing pattern.

Chewing rhythms are set by a putative central pattern generator whose output is influenced by sensory feedback. In this study we assessed how an altered feedback imposed by changing the hardness of a gum bolus modifies the timing of chewing, the maximal gape, and the activity in the masseter muscle on the chewing side. Ten adult subjects with no orofacial dysfunction chewed a standard piece of soft or hard gum for at least 3 min in random order. Vertical jaw movements were recorded with a kinesiograph and activity of the masseter muscle was recorded and integrated from surface EMG electrodes. The subjects sat in a dental chair and viewed a video lecture to distract their attention from chewing; they were instructed to chew on the right molars. Cycle-by-cycle analysis showed that 9 of the 10 subjects chewed the hard gum more slowly than the soft with no significant change in gape. The increases in cycle duration were due to changes in the duration of the opening and occlusal phases. The duration of closing was not significantly changed even though the duration and level of masseter activity were both significantly increased. We conclude that gum hardness by altering proprioceptive feedback modifies the output of the masticatory central pattern generator in such a way that the temporal aspects of chewing and the output of the masseteric motor pool are affected.

Adult↗

PubMed1989

Lana chimpanzee learns to count by "NUMATH": a summary of a videotaped experimental report.

This paper summarizes a videotaped presentation (Rumbaugh, Savage-Rumbaugh, Hopkins, Washburn, & Runfeldt, 1987) of computerized training programs whereby an adult female chimpanzee, Lana (Pan troglodytes), learned to use a joystick to remove from a screen the number of boxes appropriate to the value of a randomly selected Arabic numeral 1, 2, or 3. Initial training provided a variety of cues, both numeric and otherwise, to support correct performance. Across software programs, all cues other than numeric ones were deleted. In the final test, Lana was correct on over 80% of trials in which there was no residual feedback of intratrial events and where only her memory of those events could provide the cue to indicate that she had removed boxes in accordance with the value of the target numbers and should terminate the trial. The tape is narrated and consists of video recordings of Lana's performance on each software program.

Animals↗

PubMed2000

Extrafamilial sexual abuse: treatment for child victims and their families.

OBJECTIVES: To decrease the emotional distress of child victims of extrafamilial sexual abuse (ESA) and their families. To provide crisis intervention, individual and group treatment in response to an expressed need in the community. To pilot the use of group treatment for child victims of ESA under age 10. METHOD: This discussion describes intervention with a sample of 246 child victims, ages 2-14 years, and 323 parents who participated in the program from 1984 to 1991. This pilot project operated at a university medical facility and was located off campus in an outpatient child abuse center. Priority was given to child victims under age 7. Child victims and their families were evaluated after investigative interviews by law enforcement agencies were completed. A treatment plan was developed based on clinical assessment. Families participated in crisis counseling, individual treatment for the child victim and/or parent, Children's Treatment Groups, Parent Support Groups, or were referred to other resources. Clinical assessment of treatment progress included weekly case review by child and parent therapists, video analysis and observation of Children's Treatment Group sessions, consultation with parents and collateral contacts. RESULTS: A family approach and services for parents in addition to intervention for child victims were determined to be key components in facilitating recovery. Clinical observations and client feedback showed positive outcomes for child victims and parents with crisis counseling, Children's Treatment groups, and Parent Support Groups. The extent of intervention ranged from one session to 24 months with an average participation of 6-9 months. Follow up surveys were returned by parents for 48 child victims and results are reported. Themes, parallels in responses, and recovery factors for child victims and parents are discussed. CONCLUSIONS: The need for intervention and a community-based program was demonstrated by (1) the significant disruption in functioning that occurred for child victims of ESA and their families, (2) the risk for long term sequelae, (3) the high incidence of extrafamilial sexual abuse, and 4) the consistent, large number of requests for services. Family-centered crisis services, Children's Treatment Groups, and Parent Support Groups can be effectively based at child advocacy centers, out patient care clinics, or other community agencies. The results of formal outcome measures and longitudinal studies is needed to determine how child victims and parents benefit from specific treatment modalities and to better guide the use of limited resources.

Adolescent↗

PubMed2006

Oculomotor tracking strategy in normal subjects with and without simulated scotoma.

PURPOSE: Experiments were conducted on five subjects with no visual impairment to assess tracking strategy differences in subjects with and without a simulated central scotoma. METHODS: Subjects were asked to visually track horizontally moving periodic and nonperiodic sinusoidal stimuli through a +/-5 degrees range. Scotoma simulation was achieved electronically with a closed-loop feedback system using horizontal eye movement measurements from a monocular limbus eye tracker updated at a rate of 500 Hz. The scotoma was centrally located and had defined horizontal half widths of 1, 2, and 3 degrees . Vertical eye position measurements from a video-based dark-pupil tracker were used to identify and remove trials in which extreme vertical eye position deviations reduced the effectiveness of the simulation. RESULTS: All subjects developed a preferred retinal locus (PRL) in the left visual field and demonstrated a tendency for saccadic redirection to this area. Saccadic endpoints into the PRL outnumbered foveally directed saccades by a factor of 2:1. The PRL was located outside the compromised central vision region, typically near the edge of the scotoma boundary, for all subjects except one. This subject had a PRL within the simulated scotoma under two conditions, but the percentage of total time spent at the "compromised" PRL was less than for other subjects. CONCLUSIONS: Subjects with no visual impairment confronted with a central scotoma develop a preferred retinal locus to replace the nonfunctional fovea and appear to suppress normal refoveating saccadic behavior in favor of this location.

Adult↗

PubMed1996

[Pathologic mechanoelectric transduction of outer hair cells as the cause of recruitment].

It is believed that the sound-induced travelling wave in the mammalian cochlea is enhanced and sharpened by a positive feedback mechanism. This causes the passive linear basilar membrane growth function to become non-linear. The present paper shows that nonlinear basilar membrane vibration is due to the nonlinear growth function of the receptor potential of outer hair cells, which can be described by a 2nd-order Boltzmann function. Since intensity coding in the inner ear depends on an interaction of nonlinear basilar membrane motion and nerve fibers with three different types of synaptic threshold and growth function, the process is directly dependent on an intact mechanoelectrical transduction of outer hair cells. According to the proposed model, a loss in efficiency of outer hair cell mechanoelectrical transduction must lead to both a reduction in gain (i.e., hearing loss) and a linearizing of the response. As a result, once above threshold, the changes of stereociliary displacement, basilar membrane displacement and neural firing rate per unit change of sound intensity must be larger than for the healthy cochlea with its compressive nonlinearity.

Animals↗

PubMed1998

VIRGY: a virtual reality and force feedback based endoscopic surgery simulator.

This paper describes the VIRGY project at the VRAI Group (Virtual Reality and Active Interface), Swiss Federal Institute of Technology (Lausanne, Switzerland). Since 1994, we have been investigating a variety of virtual-reality based methods for simulating laparoscopic surgery procedures. Our goal is to develop an endoscopic surgical training tool which realistically simulates the interactions between one or more surgical instruments and gastrointestinal organs. To support real-time interaction and manipulation between instruments and organs, we have developed several novel graphic simulation techniques. In particular, we are using live video texturing to achieve dynamic effects such as bleeding or vaporization of fatty tissues. Special texture manipulations allows us to generate pulsing objects while minimizing processor load. Additionally, we have created a new surface deformation algorithm which enables real-time deformations under external constraints. Lastly, we have developed a new 3D object definition which allows us to perform operations such as total or partial object cuttings, as well as to selectively render objects with different levels of detail. To provide realistic physical simulation of the forces and torques on surgical instruments encountered during an operation, we have also designed a new haptic device dedicated to endososcopic surgery constraints. We are using special interpolation and extrapolation techniques to integrate our 25 Hz visual simulation with the 300 Hz feedback required for realistic tactile interaction. The fully VIRGY simulator has been tested by surgeons and the quality of both our visual and haptic simulation has been judged sufficient for training basic surgery gestures.

Algorithms↗