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PubMed1996

A general model for the perception of space and motion.

The perception of space and motion involves successive transformations of signals with respect to different reference systems. The visual input is coded in terms of retinal coordinates. The retinocentric values from each eye require to be unified, and to be combined with signals for eye position and movement. This egocentric reference provides a signal for the angular size, motion, or orientation of the stimulus with respect to the observer. The egocentric signals are transformed to a coordinate system that is three-dimensional-the geocentric frame of reference. Further transformations can occur at earlier levels owing to patterncentric interactions within the visual field. When the geocentric signal corresponds to the physical dimensions of space and motion, this is referred to as perceptual constancy.

Acceleration↗
PubMed2005

Building research administration applications for the academic health center: a case study.

The academic health center information environment is saturated with information of varying quality and overwhelming quantity. The most significant challenge is transforming data and information into knowledge. The University of Cincinnati Medical Center's (UCMC) focus is to develop an information architecture comprising data structures, Web services, and user interfaces that enable individuals to manage the information overload so that they can create new knowledge. UCMC has accomplished much of what is reported in this article with the help of a four-year Integrated Advanced Information Management Systems (IAIMS) operation grant awarded by the National Library of Medicine in 2003. In the UCMC vision for knowledge management, individuals have reliable, secure access to information that is filtered, organized, and highly relevant for specific tasks and personal needs. Current applications and tool sets will evolve to become the next generation knowledge management applications or smart digital services. When smart digital services are implemented, silo applications will disappear. A major focus of UCMC's IAIMS grant is research administration. Testing and building out existing and new research administration applications and digital services is underway. The authors review UCMC's progress and results in developing a software architecture, tools, and services for research administration. Included are sections on the evolution to full integration, the impact of the work at UCMC to date, lessons learned during this research and development process, and future plans and needs.

Academic Medical Centers↗
PubMed2006

[Current status of follow-up of the upper digestive tract in familial adenomatous polyposis].

Familiar adenomatous polyposis (FAP) is a hereditary disease characterized by the development of multiple adenomatous polyps in the gastrointestinal tract and colorectal cancer in practically all patients who do not receive appropriate treatment. Although the most commonly involved region in this disease is the colorectal area, it is well known that adenomas can also develop in the upper gastrointestinal tract, mainly in the periampullary area of the duodenum. Because of the possibility of malignant transformation of these polyps, adequate monitoring is required, even though the optimal follow-up schedule has not yet been defined. In the present article, we report a case of a gastric adenocarcinoma detected during the follow-up of a patient diagnosed with FAP, as well as a review of the literature on this subject. We stress the need for early detection and appropriate management of this disease. Sufficient information is available to support the use of upper gastrointestinal endoscopy with lateral vision and serial biopsies of the periampullary region in these patients. The first endoscopy in patients with FAP should be performed at the age of 20 years or at diagnosis. Subsequently, a follow-up schedule should be designed, according to the number and histological characteristics of the polyps observed.

Adenocarcinoma↗
PubMed2002

Adaptation of movement endpoints to perturbations of visual feedback.

We investigated the extent to which humans can quickly adapt their goal-directed arm movements to perturbed feedback. We predicted that the magnitude of adaptation to a changed relationship between vision and kinesthesia would depend on the type of perturbation, being largest when the perturbation can be generalized within egocentric frames of reference. To test this prediction we asked subjects to align a real 5-cm cube so that they could feel, but not see, with a simulation that they saw via a mirror. Subjects made successive movements between target locations in a sequence of adaptation and test phases. During adaptation phases, subjects received continuous visual feedback about the position of the real cube. The feedback was either veridical or perturbed. The perturbations were consistent with either a uniform translation, a scaling or a rotation. The latter two were relative to a central position between all the targets. During test phases, subjects received no visual feedback. We compared test movement endpoints after perturbed feedback with ones after veridical feedback. We found about 40% adaptation to translation, 20% to scaling and 10% to rotation. This difference in magnitude is consistent with the ease with which the transformation can be generalized within egocentric frames of reference. Changing the task so that it required different arm postures did not change the magnitude of adaptation, so postural configuration of the arm does not appear to be critical. Nevertheless, transfer to the unexposed arm was incomplete for translations and rotations, though it was complete for scaling, suggesting that at least part of the adaptation is posture based. We conclude that the adaptation to different kinds of perturbations not only differs in extent but also involves different (egocentric) mechanisms.

Adaptation, Physiological↗
PubMed2004

Planning and control of straight-ahead and angled planar movements in adults and young children.

In the present study we wanted to determine why straight-ahead movements performed along one's mid-line are directionally more accurate than movements toward eccentric targets. We also wanted to determine whether the processes underlying this difference were the same in young children as in adults. Six-to-seven-year-old children and adults practiced a video-aiming task using different starting base and target combinations without vision of their ongoing movements. The results indicated that adults and children were directionally more accurate and less variable when pointing toward targets located straight ahead of the starting base rather than eccentric or concentric targets. This was true, regardless of whether the movement was performed along one's midline or not. These results suggest that angled movements are directionally less accurate than straight-ahead movements because of difficulty in defining the orientation of the appropriate movement vector in the workspace and/or in transforming it into appropriate motor commands. A kinematic analysis revealed large coefficients of direction and of extent variability early after movement initiation. However, these coefficients of variability were largely reduced by the occurrence of peak extent velocity, revealing that noise in initial movement planning was quickly reduced by on-line control processes. Finally, the results indicated largely similar planning and control processes for young children and adults.

Adult↗
PubMed2005

Augmented virtuality based on stereoscopic reconstruction in multimodal image-guided neurosurgery: methods and performance evaluation.

Displaying anatomical and physiological information derived from preoperative medical images in the operating room is critical in image-guided neurosurgery. This paper presents a new approach referred to as augmented virtuality (AV) for displaying intraoperative views of the operative field over three-dimensional (3-D) multimodal preoperative images onto an external screen during surgery. A calibrated stereovision system was set up between the surgical microscope and the binocular tubes. Three-dimensional surface meshes of the operative field were then generated using stereopsis. These reconstructed 3-D surface meshes were directly displayed without any additional geometrical transform over preoperative images of the patient in the physical space. Performance evaluation was achieved using a physical skull phantom. Accuracy of the reconstruction method itself was shown to be within 1 mm (median: 0.76 mm +/- 0.27), whereas accuracy of the overall approach was shown to be within 3 mm (median: 2.29 mm +/- 0.59), including the image-to-physical space registration error. We report the results of six surgical cases where AV was used in conjunction with augmented reality. AV not only enabled vision beyond the cortical surface but also gave an overview of the surgical area. This approach facilitated understanding of the spatial relationship between the operative field and the preoperative multimodal 3-D images of the patient.

Algorithms↗
PubMedDate not supplied

A vision for doctoral research training in health behavior: a position paper from the American Academy of Health Behavior.

OBJECTIVE: To establish and disseminate the position of the American Academy of Health Behavior (The Academy) on doctoral research training. METHODS: A collaborative process involving the Work Group on Doctoral Research Training with input from The Academy membership led to the development of the guidelines described herein. RESULTS: A set of guidelines is provided that describe the process of learning to be a scholar/researcher and the outcomes of learning the practice of health behavior research. CONCLUSIONS: The doctoral students who are to become the stewards of our field should be prepared to engage in scholarship that creates new knowledge, uses research to transform practice, and effectively communicates research findings.

Behavioral Research↗
PubMedDate not supplied

High-performance marketing: an interview with Nike's Phil Knight. Interview by Geraldine E. Willigan.

Nike's advertising slogans--"Bo Knows," "Just Do It," and "There Is No Finish Line"--have moved beyond advertising into popular expression. Its athletic footwear and clothing have become a piece of Americana. Its brand name is as well known around the world as IBM and Coke. Behind the slogans and the flashy TV commercials is the vision of its founder, chairman, and CEO, Phil Knight. Since forming the company in 1962, Knight has taken Nike from a small-time distributor of Japanese track shoes to the top of the athletic shoe and apparel market. But not without a stumble. Along the way, Knight discovered that technological innovation alone could not continue to drive growth. When sales stagnated in the mid-1980s, Knight and Nike learned several hard lessons on how to build brands and understand consumers, and they transformed their technology company into a marketing company whose product is its most important marketing tool. "Ultimately," says Knight, "we wanted Nike to be the world's best sports and fitness company. Once you say that, you have a focus. You don't end up making wing tips or sponsoring the next Rolling Stones world tour." To keep the company growing, Nike began splitting its brands into sub-brands. In tennis, Nike divided its shoes into Challenge Court--for younger, more active players--and Supreme Court--for older, more mature players. That approach brought the company to a broader range of consumers while preserving the customer base. And to create an emotional tie with the consumer, Nike started advertising on TV. "Sports is at the heart of American culture," Knight says. "You can't explain much in 60 seconds, but when you show Michael Jordan, you don't have to. It's that simple."

Administrative Personnel↗
PubMed1991

Visual load of working with visual display terminals--introduction of VDT to newspaper editing and visual effect.

In the Japanese newspaper industry, since the late 1970s, computerization has been started in large scale. The system, called Computerized Typesetting System (CTS), has been introduced. With this system, all information in the newspaper is input into a computer, called up on a cathode ray display (CRT) to edit, and then output to film or printing plates by CTS. Thus, the work of newspaper production has undergone a major transformation from industrial work to clerical work. It was reported that newspaper production staff working with VDTs complained more than staff working with the older key system about visual and physical problems which affected their job and their daily life. The complaint rates were highest for editors, who used VDT constantly throughout the day. This study was performed to clarify the health impact of VDT use and to prevent health disorders caused by the introduction of CTS. It is concluded that 5 m corrected vision and sphere refraction of CTS workers who used CTS over 2 or 4 hr daily, significantly became worse in a year after the introduction. Therefore, it is indicated that the control of CTS work time is important to prevent the visual disorder.

Adult↗
PubMed1995

A comparison of varieties of "second-order" motion.

Bistable apparent-movement displays were created using four different kinds of "second-order" stimuli in which figures were defined by binocular disparity, spatial phase shifts of periodic luminance distributions, relative motion, and texture-element orientation differences. For each display, characteristics of the local structure of the figures, backgrounds, or both were varied. For each experimental condition, the type of apparent movement seen as a function of interstimulus interval was measured, and it was found that the relationship between perceived apparent movement and interstimulus interval differed across the types of displays viewed. The results suggest that the transformations between first-order stimulus properties and second-order motion may be too complex to imply a single uniform class of second-order motion detectors. Alternative physiological accounts of the results are discussed.

Adolescent↗
PubMed1999

Activation of the remaining hemisphere following stimulation of the blind hemifield in hemispherectomized subjects.

We used functional magnetic resonance imaging (fMRI) to investigate the neural substrates mediating residual vision in the "blind" hemifield of hemispherectomized patients. The visual stimuli were semicircular gratings moving in opposite directions on a dynamic random-dot background. They were specifically constructed to eliminate intra- and extraocular light scatter and optimize the activation of extrastriate cortical areas and their subcortical relays. Multislice T2*-weighted gradient echo (GE) echoplanar imaging (EPI) images (TR/TE = 4 s/45 ms, flip angle 90 degrees ) were acquired during activation and baseline visual stimulation. An activation minus baseline subtraction was performed, and the acquired t statistic map transformed into the stereotaxic coordinate space of Talairach and Tournoux. In seven normal control subjects, right hemifield stimulation produced significant activation foci in contralateral V1/V2, V3/V3A, VP, and V5 (MT). Significant activation was also produced in homologous regions of the right occipital lobe with left hemifield stimulation. Stimulation of the intact hemifield in hemispherectomized patients resulted in activation of similar areas exclusively within the contralateral hemisphere. Stimulation of the anopic hemifield produced statistically significant activation in the ipsilateral occipital lobe (putative area V5 or MT) and areas V3/V3A in the only subject with blindsight. We conclude that the remaining hemisphere may contribute to residual visual functions in the blind hemifield of hemispherectomized patients, possibly through the collicular-pulvinar route since the activated areas are known to receive their afferents from these subcortical nuclei.

Adult↗
PubMedDate not supplied

Computer and World Wide Web accessibility by visually disabled patients: problems and solutions.

Rapid advances in information technology have dramatically transformed the world during the past several decades. Access to computers and the World Wide Web is increasingly required for education and employment, as well as for many activities of daily living. Although these changes have improved society in many respects, they present an obstacle for visually disabled patients who may have significant difficulty processing the visual cues presented by modern graphical user interfaces. This article reviews the specific barriers to computer and Web access faced by visually disabled patients, describes clinical evaluation methods, summarizes traditional low vision methods as well as newer assistive computer technologies for universal accessibility, and discusses emerging technologies and future directions in this area.

Access to Information↗
PubMed1996

An accurate and simple method for the measurement of dental composite wear.

This study describes a relatively simple mechanical technique for measuring occlusal wear at the margin of dental restorations. The device was essentially a custom profilometer which consisted of a linear variable differential transformer with its core supported by double cantilever springs, a specially shaped stylus, a motor driven microscopic stage, custom computer software utilizing a colour coding to separate differences in slope, and a cross-hair-shaped mouse cursor to differentiate the boundary of wear. Two sets of visual standard stone casts were evaluated. The first set consisted of 17 stone replicas of machined steel dies and the second set consisted of five clinical casts, which have been used to measure the wear of composite restorations by direct vision. The reproducibility found when measuring the stone replicas of the machined steel dies was 2 microns, while, for the clinical standards, it was 16 microns.

Calcium Sulfate↗
PubMed1990

[Prediction system of facial change].

UNLABELLED: Three-dimensional simulation of facial change in a patient with severe facial deformity is very effective in not only determining a treatment plan but also in obtaining informed consent. The purpose of this presentation was to introduce the outline of our prediction system of facial change and its preliminary clinical application. (Outline of this system) This system is composed of the following three parts: Input: Three-dimensional digitized data from modified Moire Topography and coloring data of the face taken by the three-dimensional photographing appliance. ANALYSIS: Reconstruction of colored simulation model and transformation by host computer with 32 bit CPU. Output: Display of full-colored simulation model by three-dimensional graphics (Results of clinical application) 1. Three-dimensional reconstructed graphics were well accepted for clinical use, especially for the prediction in orthognathic surgery. 2. Compared with other systems, the following advantages were found: a) Simplified digitizing system using the CCD camera b) Total access time, from initial data input to display of computed picture, was about 20 minutes c) Accurate reproducibility of facial form and color vision.

Computer Graphics↗
PubMedDate not supplied

Interferometric measurements of dynamic changes of tear film.

Tear film stability plays an important role in the quality of vision. We present an interferometric method for assessing the stability of precorneal tear film in real time. A lateral shearing technique is applied as a noninvasive and sensitive method for investigating tear film stability and the smoothness of the tear film surface by quantitative evaluation of the interference fringe pattern. The evaporation of tears and the appearance of tear film break-up between blinks cause changes in the fringe geometry. For quantitative assessment of the fringe smoothness and consequently of the tear film structure, the fast Fourier transform (FFT) is applied. Four parameters are used to quantitatively estimate dynamic changes in the tear film stability of the cornea 20 s after the eye blink. Examples of examined interferograms recorded in patients with healthy eyes, patients suffering from dry-eye syndrome, and patients wearing contact lenses are given. Significant differences between the stability of the tear film in the healthy eye and that in the dry eye and the eye with a contact lens are observed. The favorable influence of artificial tears applied in patients with dry-eye syndrome or contact lenses is also discussed.

Dry Eye Syndromes↗
PubMed2005

A new image representation algorithm inspired by image submodality models, redundancy reduction, and learning in biological vision.

We develop a new biologically motivated algorithm for representing natural images using successive projections into complementary subspaces. An image is first projected into an edge subspace spanned using an ICA basis adapted to natural images which captures the sharp features of an image like edges and curves. The residual image obtained after extraction of the sharp image features is approximated using a mixture of probabilistic principal component analyzers (MPPCA) model. The model is consistent with cellular, functional, information theoretic, and learning paradigms in visual pathway modeling. We demonstrate the efficiency of our model for representing different attributes of natural images like color and luminance. We compare the performance of our model in terms of quality of representation against commonly used basis, like the discrete cosine transform (DCT), independent component analysis (ICA), and principal components analysis (PCA), based on their entropies. Chrominance and luminance components of images are represented using codes having lower entropy than DCT, ICA, or PCA for similar visual quality. The model attains considerable simplification for learning from images by using a sparse independent code for representing edges and explicitly evaluating probabilities in the residual subspace.

Algorithms↗
PubMed1997

[Diagnosis and therapy of lymphoid tumors of the orbits].

For the evaluation of neoplastic orbital lesions an interdisciplinary concept is crucial and includes modern imaging techniques as well as rhinosurgical approaches to the orbit. During a 14-year period 6 primary malignant orbital lymphomas and 9 cases of orbital pseudotumors were managed at our department. In most of the cases an exophthalmus with painful swelling of the eyelids, diplopia and a loss of vision were the clinical symptoms. Imaging using CT or MRI revealed homogeneous tissue formations that could not be clearly demarcated from adjacent orbital structures. By a rhinosurgical approach a biopsy was performed of each lesion without surgical complications. Following diagnosis the localized malignant lymphomas of the orbit were irradiated. In one patient systemic spread of tumor required multi-drug chemotherapy. Two patients died as the result of the sequleae of disseminated plasmocytomas. Patients with orbital pseudotumors were treated with systemic steroids. Two patients were also irradiated. No malignant transformation of any orbital pseudotumor was observed in this series. Our experiences show that careful histological evaluation of lymphoid orbital masses is necessary for correct diagnosis, especially since this has great impact on treatment and prognosis. Depending on the localization of a lesion medial orbitotomy by a rhinosurgical approach has proven to be a safe method for performing a biopsy or extirpating tumor.

Adult↗
PubMed2006

Unilateral neglect: a theory of proprioceptive space of a stimulus as determined by the cerebellar component of motor efference copy (and is autism a special case of neglect).

Unilateral neglect is a devastating condition, which manifests as a loss of a person's spatial awareness opposite the damaged side of the brain. It challenges our conception of the seat of the soul and its explanation is at the heart of the mind-body problem. A heuristic definition of the dorsal stream of a modality is here based on the categorization of parietal networks by the cerebellar component of motor efference copy. Taking this premise, the proprioceptive space of a stimulus is established as a concept in this paper. It is proposed that unilateral neglect is typically a dysfunction of proprioceptive space of a stimulus associated with lesions of the dorsal stream. Furthermore, most experimental findings of unilateral visual neglect (and by extrapolation, other sensory modalities), can be explained by two developmental mechanisms by which the proprioceptive space of a stimulus is encoded in the parietal cortex. Its right and left hemisphere representation can be dissociated from the hemifield of presentation of perceptual information, such that the left hemifield can have a left hemisphere representation through callosal connections and likewise, the right hemifield can have a right hemifield representation. The processing of a sensory stimulus in either parietal hemisphere is dynamically determined as shown by experimental modulation of performance. A theory of historical precedence will provide a developmental background to the organization of proprioceptive space and will invoke separate models according to specified terms of engagement. A model based on the expansion and contraction of the proprioceptive space of a stimulus as a gradient across both hemispheres and modulated by concurrent proprioceptive state will be differentiated from a model that is non-graduating but competitive and lacks such modulation. In other words, the dorsal representation of a sensory stimulus in the former case is shared to a varying degree by the two parietal hemispheres, whereas in the latter case the representation of left and right aspects of the same object stimulus is strictly divided between the two hemispheres. A further hypothesis of a dorsoventral gradient of the peripheral and foveal components of proprioceptive space characterizing dorsal stream networks will predict the double dissociation revealed by experimental paradigms. It will explain why some patients show neglect only in foveal while others only in peripheral vision. The paper proposes to unify neglect, extinction and optic ataxia on the one hand, and spatial and object-based neglect on the other hand, under a singularly proficient paradigmatic structure. A binding model as described is a component theory that acknowledges how the involved pathways or transitional zones in a pathway may contribute to a differential clinical picture as one progresses from posterior to anterior parietal cortex. Finally, a brief discussion is given on how autistic subjects neglect spatial cues and the inability of a spatial cognitive transformation underlies the impairments postulated for 'a theory of mind'.

Autistic Disorder↗