Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Motion”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 1,117 records · Page 62Linked to original sources
PubMed2001

Early dynamic motion versus postoperative immobilization in patients with extensor indicis proprius transfer to restore thumb extension: a prospective randomized study.

Transfer of the extensor indicis proprius is the gold standard for reconstruction of the extensor pollicis longus tendon to restore thumb extension. Twenty patients were included to a prospective randomized trial to assess whether an early dynamic motion protocol yields a better outcome than immobilization. Evaluation included postoperative range of motion, grip strength, duration of treatment, and time off work. Ten patients of each group had the thumb immobilized in an extension thumb spica cast for 3 weeks after surgery or underwent an early dynamic motion protocol. Follow-up examinations were performed 3, 4, 6, and 8 weeks after surgery. At 3 weeks total range of motion of the interphalangeal joint was almost twice as good (59 degrees ) in the dynamic motion group compared with immobilized patients (31 degrees ). At 6 weeks no significant differences between the groups were found. A similar pattern for grip strength and pinch grip was found after 3 weeks, when patients undergoing the motion protocol had significantly better results than the immobilized group. Although the dynamic motion group still had better results after 4 weeks, hand function was similar in both groups after 6 and 8 weeks. Patients with early dynamic motion recovered their hand function more rapidly than immobilized patients, shortening total rehabilitation time and making dynamic motion treatment highly cost-effective.

Adult↗
PubMedDate not supplied

[Arm motion analysis: a new method and its clinical application].

AIM: An investigation into the objective criteria of shoulder mobility possesses special meaning for diagnostic documentation, the evaluation of therapy and the effects of rehabilitation in the treatment of diseases of the shoulder. In order to ascertain the criteria which characterise shoulder mobility, it is necessary to have a tool available that is objective, comparable and allows the complexity, variability and range of motion to be recorded. Motion analysis represents one such standard procedure used to measure joint movement. METHOD: Accordingly, a marker- based motion analysis of the wrist and elbow, a marker-based three-dimensional motion analysis system for the upper extremities was developed. We evaluated 10 healthy subjects without shoulder conditions and 8 patients with impingement syndrome (7 operative, 1 conservative therapy). RESULTS: The healthy subjects revealed a reproducible motion curve for the specific motion tested. The curves were defined as the normal standard and we used them for comparative purposes. In the treatment group, an improvement of the 3D range of motion could be documented for the affected shoulder following rehabilitation. CONCLUSION: It can be stated that this newly developed marker-based procedure for the three-dimensional motion analysis is suitable for recording complex unconstrained movements. This was found to be more relevant for the assessment of the ability of patients to manage the physical demands of daily living than traditional clinical tests. Furthermore, the information gained from motion analysis of the upper extremities will play a valuable role in the future for quality control during diagnosis and treatment, as well as for the design of shoulder rehabilitation programs.

Adult↗
PubMed2003

[Operative procedure for repair of the dorsal aponeurosis promoting early active motion].

PURPOSE: To describe our method of treatment for extensor tendon laceration at the level of the distal and proximal interphangeal joint with early active motion following a special tendon suture and to evaluate the outcome. METHODS: In a retrospective study the results of 35 patients with 35 extensor tendon lacerations in zone 1 and 2, in whom the postoperative treatment consisted of immobilisation, were compared with the results of 24 patients, in whom 24 extensor tendon lacerations in zone 1 and 2 were treated with early active motion following operative treatment. In addition, the outcome following immobilisation after operative treatment of 54 patients with 57 extensor tendon lacerations in zone 3 was compared to the outcome of 61 patients, who had undergone early active motion following operative treatment, with 65 extensor tendon lacerations in zone 3. In patients, treated with early active motion, a special type of tendon suture was carried out. The outcome was ranked according to a scoring system developed by us. RESULTS: In extensor tendon laceration in zone 1 and 2 following active early motion there were 62.5 % excellent, 20.8 % good, 12.5 % satisfactory, and 4.2 % unsatisfactory results. In patients with extensor tendon lacerations in zone 1 and 2, in whom the postoperative treatment consisted of immobilisation, 45.7 % excellent, 22.9 % good, 20 % satisfactory, and 11.4 % unsatisfactory results were found. Following early active motion in patients with zone 3 extensor tendon laceration, there were 70.8 % excellent, 15.4 % good, 9.2 % satisfactory, and 4.6 % unsatisfactory results. After postoperative immobilisation 59.7 % excellent, 14 % good, 12.3 % satisfactory, and 14 % unsatisfactory results were found. For extensor tendon laceration in zone 1 and 2, there was a tendency to much better results in the early active motion group. However, the differences in the outcome of the two treatment groups were not statistically significant. There were significantly more good and excellent results and less unsatisfactory results in zone 3 extensor tendon lacerations following early active motion than following immobilisation. CONCLUSION: This data suggests that patients benefit by early active motion rehabilitation protocol following operative treatment for extensor tendon lacerations in zone 1 to 3. Our special tendon suture proved in the practice well.

Adolescent↗
PubMed1993

Asymmetries in the sensitivity to motion in depth: a centripetal bias.

It is reasonable to ask whether observers are more sensitive to the pattern of image motion caused by forward locomotion through the environment than to the pattern caused by backward locomotion. The distribution of sensitivities of cells in MT does show such a bias, although this bias is minimal at small eccentricities. Additionally, both locomotion-induced stimulation and the sensitivities of MT cells suggest greater sensitivity should be obtained in the lower visual field. Previous research on this issue has usually employed frontoparallel motion in patterns presented to one side of the fixation point. Both centrifugal and centripetal biases have been obtained. In this study the stimuli present motion signals that travel radially from (or towards) the fixation point. These stimuli, which produce a strong percept of motion in depth, are an adaptation of the global-dot-motion stimulus employed by Newsome and Pare. With these stimuli we find that sensitivity to motion in depth is greater in the lower visual field than in the upper visual field, and that sensitivity is greater to centripetal motion than to either centrifugal or frontoparallel motion. This centrifugal bias in sensitivity decreases with eccentricity. The last two findings contradict the notion that the bias is produced by the visual experience induced by normal forward locomotion and also that the detection of motion in depth is subserved by MT.

Adult↗
PubMed1995

Processing speed in the motion-induction effect.

The motion-induction effect, where an illusory motion is perceived within a bar when it is shown next to a spot presented slightly earlier, was studied with respect to the idea that it is based on differential processing speeds between the two ends of the bar. First, by using just a bar with a luminance gradient, the existence of a motion illusion (gradient motion) within such a bar was demonstrated, presumably due to the different processing speeds of differential luminances. When such a bar was used in the motion-induction effect, it was shown to modulate, for short delays, the strength of the effect up or down, according to the direction of the gradient with respect to the position of the spot. When the same bar was used in the double-motion-induction effect (split priming), in which motion is usually away from the later spot, it totally determined the perceived direction of illusory motion, independently of gradient direction with respect to the later spot or the time between the two spots. These results demonstrate, on the one hand, that differential local processing speed is a likely mechanism to underlie the motion-induction effect. On the other hand, they also suggest the involvement of other more global (and perhaps top-down) processes.

Analysis of Variance↗
PubMed1996

Motion perception: a modern view of Wertheimer's 1912 monograph.

Max Wertheimer's 1912 monograph on apparent motion is a seminal contribution to the study of visual motion, but its actual contents are not widely known. This article attempts to clarify what the monograph did and did not contribute, emphasizing links between Wertheimer's principal findings and the results of subsequent investigations of motion perception, including currently active lines of research. The topics discussed include Wertheimer's experimental tests of explanations for apparent motion; his work with motion phenomena that lie between succession and optimum motion; his studies of the influence of attention on motion; explorations of various forms of hysteresis and motion transparency; and Wertheimer's work with a motion-blind patient.

History, 20th Century↗
PubMed2000

When texture takes precedence over motion in depth perception.

Both texture and motion can be strong cues to depth, and estimating slant from texture cues can be considered analogous to calculating slant from motion parallax (Malik and Rosenholtz 1994, report UCB/CSD 93/775, University of California, Berkeley, CA). A series of experiments was conducted to determine the relative weight of texture and motion cues in the perception of planar-surface slant when both texture and motion convey similar information. Stimuli were monocularly viewed images of planar surfaces slanted in depth, defined by texture and motion information that could be varied independently. Slant discrimination biases and thresholds were measured by a method of single-stimuli binary-choice procedure. When the motion and texture cues depicted surfaces of identical slants, it was found that the depth-from-motion information neither reduced slant discrimination thresholds, nor altered slant discrimination bias, compared to texture cues presented alone. When there was a difference in the slant depicted by motion and by texture, perceived slant was determined almost entirely by the texture cue. The regularity of the texture pattern did not affect this weighting. Results are discussed in terms of models of cue combination and previous results with different types of texture and motion information.

Analysis of Variance↗
PubMed2001

The integration of orientation information in the motion correspondence problem.

We examine how differently oriented components contribute to the discrimination of motion direction along a horizontal axis. Stimuli were two-frame random-dot kinematograms that were narrowband filtered in spatial frequency. On each trial, subjects had to state whether motion was to the left or the right. For each stimulus condition, Dmax (the largest displacement supporting 80% correct direction discrimination performance) was measured. In experiment 1, Dmax was measured for orientationally narrowband stimuli as a function of their mean orientation. Dmax was found to increase as the orientation of the stimuli became closer to the axis of motion. Experiment 2 used isotropic stimuli in which some orientation bands contained a coherent motion signal, and some contained only noise. When the noise band started at vertical orientations and increased until only horizontal orientations contained a coherent motion signal, Dmax increased slightly. This suggests that near-vertical orientations interfere with motion perception at large displacements when they contain a coherent motion signal. When the noise band started at horizontal and increased until only vertical orientations contained the motion signal, Dmax decreased steadily. This implies that Dmax depends at least partly on the most horizontal motion signal in the stimulus. These results were contrasted with two models. In the first, the visual system utilises the most informative orientations (nearest horizontal). In the second, all available orientations are used equally. Results supported an intermediate interpretation, in which all orientations are used but more informative ones are weighted more heavily.

Discrimination, Psychological↗
PubMed1999

Perceptual motion standstill in rapidly moving chromatic displays.

In motion standstill, a quickly moving object appears to stand still, and its details are clearly visible. It is proposed that motion standstill can occur when the spatiotemporal resolution of the shape and color systems exceeds that of the motion systems. For moving red-green gratings, the first- and second-order motion systems fail when the grating is isoluminant. The third-order motion system fails when the green/red saturation ratio produces isosalience (equal distinctiveness of red and green). When a variety of high-contrast red-green gratings, with different spatial frequencies and speeds, were made isoluminant and isosalient, the perception of motion standstill was so complete that motion direction judgments were at chance levels. Speed ratings also indicated that, within a narrow range of luminance contrasts and green/red saturation ratios, moving stimuli were perceived as absolutely motionless. The results provide further evidence that isoluminant color motion is perceived only by the third-order motion system, and they have profound implications for the nature of shape and color perception.

Color Perception↗
PubMed2001

Direction of motion discrimination after early lesions of striate cortex (V1) of the macaque monkey.

Previous studies have established that humans and monkeys with damage to striate cortex are able to detect and localize bright targets within the resultant scotoma. Electrophysiological evidence in monkeys suggests that residual vision also might include sensitivity to direction of visual motion. We tested whether macaque monkeys with longstanding lesions of striate cortex (V1), sustained in infancy, could discriminate visual stimuli on the basis of direction of motion. Three monkeys with unilateral striate cortex lesions sustained in infancy were tested 2-5 years postlesion on a direction of motion discrimination task. Each monkey was trained to make saccadic eye movements to a field of moving dots or to withhold such eye movements, depending on the direction of motion in a coherent random dot display. With smaller motion displays, monkeys were unable to detect or discriminate motion within the scotoma, although they could discriminate moving from static stimuli. Yet, each monkey was able to discriminate direction of motion when the motion stimulus was larger, but still confined to the scotoma. The results demonstrate that the recovery after infant damage to striate cortex includes some sensitivity to direction of visual motion.

Aging↗
PubMed2004

Why does outer joint motion predominate in bipolar hip prosthesis? Experimental and clinical studies.

BACKGROUND: Theoretically, the motion of a bipolar hip prosthesis is most likely to occur at the inner joint if the frictional coefficients are equal at both surfaces. However, many studies have suggested that most motion occurs at the outer joint. MATERIAL AND METHODS: We performed an analysis of motion in a cadaveric bone model and in 50 patients during fluoroscopic examination, to determine how the motion is distributed between the two joints and what factors contribute to this distribution. RESULTS: The motion distributions varied widely between the patients. However, there was a relative pre-ponderance (63-90%) of outer motion in all directions of leg movement in addition to a persistent coexistence of motion at both joints in 44 of 50 patients. This preponderance of outer motion was the result of an early impingement of the acetabular cup and structural differences between the two joints. INTERPRETATION: An adjustment of the positive eccentricity and a decrease in the frictional torque of the inner joint as a result of better lubrication and smoothness can be expected to improve the motion distribution, thus reducing the amount of acetabular erosion.

Adult↗
PubMed1994

The brain activity related to residual motion vision in a patient with bilateral lesions of V5.

We have used the technique of PET to chart the cortical areas activated by visual motion in the brain of a patient with a severe impairment in the ability to recognize the motion of objects (akinetopsia), following bilateral lesions which have so far been presumed to include area V5. High resolution MRI of her brain showed that the zone occupied by area V5 had indeed been destroyed bilaterally. Positron emission tomography activation images, co-registered to the MRIs, showed three principal regions of the cortex activated by motion. These were located (i) bilaterally in the precuneus of superior parietal cortex (area 7 of Brodmann); (ii) bilaterally in the cuneus (a region considered to represent upper V3); (iii) in the left lingual and fusiform gyri (possibly lower V3 and adjacent areas). In contrast to normal subjects, there was no significant activation of area V1 or V2. The stimuli used for scanning were chosen by prior testing of the patient's visual capacities. The control stimulus was a static random distribution of light squares on a dark background. In the moving stimulus these squares moved coherently, the direction of motion changing periodically between the cardinal directions (left, right, up and down). It was ascertained that the patient could correctly identify these directions. We also found (i) that her occasional errors were always in the direction opposite to the motion presented, so that her identification of axis of motion (i.e. vertical or horizontal) was 100% correct; (ii) that when a few static squares were added to the moving the display her identification of direction fell to chance but her identification of the axis of motion remained 100%; (iii) that when a few squares moving opposite and orthogonal to the predominant direction of motion were incorporated, her performance on both direction and axis fell to chance; (iv) that she was unable to identify motion in oblique directions between the horizontal or vertical axes, always guessing one of the cardinal directions. In accounting for her residual vision in terms of cortex, which remains active, we hypothesize; (i) that the bilateral loss of V5 has affected direction sensitive mechanisms at other sites in the cortex which are interconnected with V5 and (ii) that in consequence her performance on our tests reflects the properties of dynamic orientation selective mechanisms that were also differentially activated by the stimuli used during scanning.

Adult↗
PubMed1998

Reciprocal inhibitory visual-vestibular interaction. Visual motion stimulation deactivates the parieto-insular vestibular cortex.

The vestibular system--a sensor of head accelerations--cannot detect self-motion at constant velocity and thus requires supplementary visual information. The perception of self-motion during constant velocity movement is completely dependent on visually induced vection. This can be linear vection or circular vection (CV). CV is induced by large-field visual motion stimulation during which the stationary subject perceives the moving surroundings as being stable and himself as being moved. To determine the unknown cortical visual-vestibular interaction during CV, we conducted a PET activation study on CV in 10 human volunteers. The PET images of cortical areas activated during visual motion stimulation without CV were compared with those with CV. Hitherto, CV was explained neurophysiologically by visual-vestibular convergence with activation of the vestibular nuclei, thalamic subnuclei and vestibular cortex. If CV were mediated by the vestibular cortex, one would expect that an adequate visual motion stimulus would activate both the visual and vestibular cortex. Contrary to this expectation, it was shown for the first time that visual motion stimulation with CV not only activates a medial parieto-occipital visual area bilaterally, separate from middle temporal/medial superior temporal areas, it also simultaneously deactivates the parieto-insular vestibular cortex. There was a positive correlation between the perceived intensity of CV and relative changes in regional CBF in parietal and occipital areas. These findings support a new functional interpretation: reciprocal inhibitory visual-vestibular interaction as a multisensory mechanism for self-motion perception. Inhibitory visual-vestibular interaction might protect visual perception of self-motion from potential vestibular mismatches caused by involuntary head accelerations during locomotion, and this would allow the dominant sensorial weight during self-motion perception to shift from one sensory modality to the other.

Adult↗
PubMed2001

Motion discrimination in cortically blind patients.

Some patients with brain damage affecting the striate cortex, though clinically blind in their field defects, can still discriminate visual stimuli when forced choice procedures are used. Such patients seem particularly sensitive to moving stimuli in their scotomata, though there are conflicting reports as to whether they can discriminate the direction of motion. We tested three patients with areas of cortical blindness for their ability to detect and discriminate the direction of motion of a variety of first-order motion stimuli, namely bars, gratings, plaids and random dot kinematograms depicting translation and motion in depth, during forced choice tasks. The patients could detect the presence of movement in any kind of stimulus, and could discriminate the direction of single bars, but none could discriminate the direction of motion of the more complex stimuli (gratings, plaids and random dot kinematograms) or discriminate between 0 and 100% coherent random dot kinematograms at any speed tested (from 4 to 64 degrees /s). Similar results were obtained from one of the patients who was additionally tested with second-order versions of the translated bar and random dot kinematograms, eliminating light scatter as an explanation. Overall, the results suggest that motion processing in the scotoma is severely impaired, and that the puzzling discrepancies between previous studies can be accounted for by the type of stimulus used. The motion discrimination impairment caused by brain damage affecting the primary visual cortex is inconsistent with the proposed existence of a subcortical pathway to extrastriate cortical motion areas (such as areas MT and MST) which bypasses the striate cortex and is specialized for analysing 'fast' motion.

Adult↗
PubMed2004

Training-induced recovery of visual motion perception after extrastriate cortical damage in the adult cat.

Unilateral ibotenic acid lesions of the lateral suprasylvian (LS) cortex severely impair the ability of cats to integrate local motion signals (measured as direction range thresholds) and to extract motion signals from noise (measured as motion signal thresholds) in their contra-lesional visual hemifields. These deficits were found up to several months after the lesions and were limited to thresholds measured with random-dot stimuli, while contrast sensitivity for discriminating the direction of motion of sine-wave gratings remained unaffected. Our goal was to determine whether deficits of complex motion perception could recover and whether the recovery was spontaneous or required retraining. In each cat, a single location in the impaired visual hemifield was selected for visual retraining, which required the animals to discriminate motion direction using random-dot stimuli in which the range of dot directions was varied. Fifteen to 40 days of intensive retraining led to a gradual, complete recovery of motion integration. The recovery was stimulus specific since it did not transfer from direction range to motion signal thresholds, and it was largely restricted to the visual field locations retrained. Delaying the onset of retraining by several days to several months had no significant impact on the extent or rate of recovery. Once recovery was achieved, performance remained stable over a period of several months. These results suggest that recovery of complex visual motion perception after lesions of extrastriate visual cortex is an active process that requires extensive, stimulus- and retinotopically-specific visual retraining.

Animals↗
PubMed2006

Neural correlates of coherent audiovisual motion perception.

Real-life moving objects are often detected by multisensory cues. We investigated the cortical activity associated with coherent visual motion perception in the presence of a stationary or moving auditory noise source using functional magnetic resonance imaging. Twelve subjects judged episodes of 5-s random-dot motion containing either no (0%) or abundant (16%) coherent direction information. Auditory noise was presented with the displayed visual motion that was moving in phase, was moving out-of-phase, or was stationary. Subjects judged whether visual coherent motion was present, and if so, whether the auditory noise source was moving in phase, was moving out-of-phase, or was not moving. Performance was greatest for a moving sound source that was in phase with the visual coherent dot motion compared with when it was in antiphase. A random-effects analysis revealed that auditory motion activated extended regions in both cerebral hemispheres in the superior temporal gyrus (STG), with a right-hemispheric preponderance. Combined audiovisual motion led to activation clusters in the STG, the supramarginal gyrus, the superior parietal lobule, and the cerebellum. The size of the activated regions was substantially larger than that evoked by either visual or auditory motion alone. The congruent audiovisual motion evoked the most extensive activation pattern, exhibiting several exclusively activated subregions.

Acoustic Stimulation↗
PubMed1998

A database of macromolecular motions.

We describe a database of macromolecular motions meant to be of general use to the structural community. The database, which is accessible on the World Wide Web with an entry point at http://bioinfo.mbb.yale.edu/MolMovDB , attempts to systematize all instances of protein and nucleic acid movement for which there is at least some structural information. At present it contains >120 motions, most of which are of proteins. Protein motions are further classified hierarchically into a limited number of categories, first on the basis of size (distinguishing between fragment, domain and subunit motions) and then on the basis of packing. Our packing classification divides motions into various categories (shear, hinge, other) depending on whether or not they involve sliding over a continuously maintained and tightly packed interface. In addition, the database provides some indication about the evidence behind each motion (i.e. the type of experimental information or whether the motion is inferred based on structural similarity) and attempts to describe many aspects of a motion in terms of a standardized nomenclature (e.g. the maximum rotation, the residue selection of a fixed core, etc.). Currently, we use a standard relational design to implement the database. However, the complexity and heterogeneity of the information kept in the database makes it an ideal application for an object-relational approach, and we are moving it in this direction. Specifically, in terms of storing complex information, the database contains plausible representations for motion pathways, derived from restrained 3D interpolation between known endpoint conformations. These pathways can be viewed in a variety of movie formats, and the database is associated with a server that can automatically generate these movies from submitted coordinates.

Computer Simulation↗
PubMed1996

Effects of motion on the performance of pulse oximeters in volunteers.

BACKGROUND: Pulse oximetry is considered a standard of care in both the operating room and the postanesthetic care unit, and it is widely used in all critical care settings. Pulse oximeters may fail to provide valid pulse oximetry data in various situations that produce low signal-to-noise ratio. Motion artifact is a common cause of oximeter failure and loss of accuracy. This study compares the accuracy and data dropout rates of three current pulse oximeters during standardized motion in healthy volunteers. METHODS: Ten healthy volunteers were monitored by three different pulse oximeters: Nellcor N-200, Nellcor N-3000, and Masimo SET (prototype). Sensors were placed on digits 2, 3, and 4 of the test hand, which was strapped to a mechanical motion table. The opposite hand was used as a stationary control and was monitored with the same pulse oximeters and an arterial cannula. Arterial oxygen saturation rate varied from 100% to 75% by changing the inspired oxygen concentration. While pulse oximetry was both constant and changing, the oximeter sensors were connected before and during motion. Oximeter errors and dropout rates were digitally recorded continuously during each experiment. RESULTS: If the oximeter was functioning before motion began, the following are the percentages of time when the instrument displayed a pulse oximetry value within 7% of control: N-200 = 76%, N-3000 = 87%, and Masimo = 99%. When the oximeter sensor was connected after the beginning of motion, the values were N-200 = 68%, N-3000 = 47%, and Masimo = 97%. If the alarm threshold was chosen as pulse oximetry less than 90%, then the positive predictive values (true alarms/ total alarms) are N-200 = 73%, N-3000 = 81%, and Masimo = 100%. In general, N-200 had the greatest pulse oximetry errors and N-3000 had the highest dropout rates. CONCLUSIONS: The mechanical motions used in this study significantly affected oximeter function, particularly when the sensors were connected during motion, which requires signal acquisition during motion. The error and dropout rate performance of the Masimo was superior to that of the other two instruments during all test conditions. Masimo uses a new paradigm for oximeter signal processing, which appears to represent a significant advance in low signal-to-noise performance.

Adult↗