Helical scan video-tape recorders--a survey.
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Tape Recording↗
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Standardization of slant-track video-tape recorders.
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Tape Recording↗
Video-tape recording as an aid to behaviour therapy.
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Adolescent↗
Some uses of video-tape recording in language rehabilitation after brain damage.
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Brain Damage, Chronic↗
Polaroid type 611 video image recording land film for copying radiographs.
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Humans↗
Function of the heterocercal tail in white sturgeon: flow visualization during steady swimming and vertical maneuvering.
Basal ray-finned fishes possess a heterocercal tail in which the dorsal lobe containing the extension of the vertebral column is longer than the ventral lobe. Clarifying the function of the heterocercal tail has proved elusive because of the difficulty of measuring the direction of force produced relative to body position in the aquatic medium. We measured the direction of force produced by the heterocercal tail of the white sturgeon (Acipenser transmontanus) by visualizing flow in the wake of the tail using digital particle image velocimetry (DPIV) while simultaneously recording body position and motion using high-speed video. To quantify tail function, we measured the vertical body velocity, the body angle and the path angle of the body from video recordings and the vortex ring axis angle and vortex jet angle from DPIV recordings of the wake downstream from the tail. These variables were measured for sturgeon exhibiting three swimming behaviors at 1.2 L s(-)(1), where L is total body length: rising through the water column, holding vertical position, and sinking through the water column. For vertical body velocity, body angle and path angle values, all behaviors were significantly different from one another. For vortex ring axis angle and vortex jet angle, rising and holding behavior were not significantly different from each other, but both were significantly different from sinking behavior. During steady horizontal swimming, the sturgeon tail generates a lift force relative to the path of motion but no rotational moment because the reaction force passes through the center of mass. For a rising sturgeon, the tail does not produce a lift force but causes the tail to rotate ventrally in relation to the head since the reaction force passes ventral to the center of mass. While sinking, the direction of the fluid jet produced by the tail relative to the path of motion causes a lift force to be created and causes the tail to rotate dorsally in relation to the head since the reaction force passes dorsal to the center of mass. These data provide evidence that sturgeon can actively control the direction of force produced by their tail while maneuvering through the water column because the relationship between vortex jet angle and body angle is not constant.
Animals↗
Digital video for the documentation of colonoscopy.
BACKGROUND: The aim of this study was to determine whether digital video is suitable for the documentation of colonoscopy. Standards are required for the visual documentation of endoscopic findings and to optimize image quality while limiting file size and bandwidth requirements. METHODS: Video recordings of colonoscopy procedures were encoded using a common video compression method at selected data rates and resolutions. Twelve reviewers were selected, each of whom was assigned 8 video review sessions, each consisting of 5 colonoscopy procedures. The reviewers rated the following: level of confidence that the cecum was demonstrated, subjective quality of the video compared with actual videocolonoscopy, and whether the video was of "diagnostic quality." RESULTS: Reviewers were confident that the cecum was demonstrated in all cases except at the lowest data rate. The 1.0 Mbps standard interchange format video provided an optimal balance between quality and file size. CONCLUSIONS: For the documentation of colonoscopy, 1.0 Mbps is acceptable and results in a file size of 7.5 Mbytes/min, which is manageable for most modern hospital and telehealth networks.
Colonoscopy↗
Evaluation of a new measurement tool for facial paralysis reconstruction.
Evaluation of facial movement, including distance and direction, is essential for anyone interested in facial paralysis reconstruction. The authors' goal was to develop a measurement system that is simple, uses commercially available equipment, takes little time, and provides meaningful and accurate measurements. This technique is called the facial reanimation measurement system. It involves placing dots around the patient's mouth and video recording the patient performing maximal effort smiles. Using a video editing program, one frame showing the patient at rest is overlaid with a second frame showing the patient's smile. This overlaid image is imported into Adobe PhotoShop, where measurements are obtained using tools available in the program. Twenty patients were used to test interrater and intrarater reliability of the facial reanimation measurement system. The accuracy of the measurement process was tested by comparing 10 known distances and angles with those obtained using the facial reanimation measurement system. Both intrarater and interrater reliability of the distance and angle measurements are highly accurate, with intraclass correlations greater than 0.9. The facial reanimation measurement system is accurate to within 0.6 mm and 2.0 degrees when compared with a "known" distance and angle. The facial reanimation measurement system has been used to measure smile movements of more than 200 patients and has been demonstrated to be valuable for detecting changes of facial movements over time. This system is simple and economical and only requires 20 minutes to perform. Although the authors demonstrated evaluation of smile movement, the system may be used to evaluate other movements, such as mouth puckering, eye closure, and forehead elevation.
Adult↗
Standardized evaluation of CT angiography with remote generation of 3D video sequences for the detection of intracranial aneurysms.
Computed tomography (CT) angiography is a well-known imaging technique commonly applied to both the detection and therapy planning of intracranial aneurysms. For this purpose, current studies predominantly focus on three-dimensional (3D) representations of CT angiographic volumes obtained with varying visualization approaches on different computers. Interactive manipulation performed by users individually is an important prerequisite for data analysis. However, this leads to inconsistent and barely reproducible 3D visualization results. Furthermore, the quality of any 3D representation depends on the applied visualization strategy (eg, maximum-intensity projection, shaded-surface display, direct volume rendering). To overcome these limitations, the authors present a novel method for standardized visualization of CT angiographic volumes, consisting of three steps: (a) transfer of the image data to a remote high-end graphics workstation, (b) automatic 3D visualization with high-resolution direct volume rendering, and (c) consecutive video generation performed according to a standardized protocol. The recorded video sequences are transferred for evaluation to a local desktop computer. In the experimental setup, high-quality videos based on 3D visualizations were produced in less than 60 minutes per patient. Although aneurysms above the skull base are usually visualized with excellent quality, the analysis of aneurysms at the skull base is still difficult.
Angiography↗
Measuring three dimensions of eye movement in dynamic situations by means of videooculography.
A primary function of the vestibular system is the stabilisation of the eye during head movement. Consequently, evaluation of reflex eye movements represents an essential means to both clinical diagnosis and researching of the vestibular function. Movements in the eye can be resolved into three orthogonal components, i.e. horizontal, vertical and torsional. As an improvement on most current techniques, which provide only measurement of the horizontal and vertical components, videooculography (VOG) facilitates non-invasive measurement of all three of the defined components. To date, only the scleral coil technique, which involves the semi-invasive placement of coil rings onto the bulbi, yields a continuous measure of eye torsion. Employment of suitable solid-state devices permit the integration of a compact, high resolution video recording system. In the basic configuration, eye movements can be observed and simultaneously recorded for later analysis or documentation. The video images of the eye are obtained by means of a miniaturised CCD video sensor mounted on a light-occluding mask. Image processing of the acquired video images determines horizontal and vertical coordinates of eye position online. Ocular torsion, as reflected by the rotation of the natural iris, is measured for each video frame. The VOG algorithm has been implemented on a PC based workstation, which permits online observation, recording and evaluation of eye movements. In addition, the technique has found clinical application as a portable eye-movement observation and recording system, allowing bedside examination and recording of transient symptoms. Preliminary results from various studies, including the objective evaluation of positional nystagmus (BPPN), are presented.
Eye Movements↗
Pliability of the vocal fold mucosa in relation to the mucosal upheaval during phonation.
OBJECTIVES: To quantitatively evaluate the effect of vocal fold lengthening on pliability of the mucosa measured along the superior-inferior axis and to examine the relation of the location of mucosal upheaval (MU) during phonation to the changes in pliability pattern of the mucosa when the vocal fold was lengthened. DESIGN: Investigation of mechanical characteristics of the vocal fold in relation to the MU during phonation. MATERIALS: Five excised canine larynges. INTERVENTIONS: Vibrations with and without vocal fold lengthening were recorded from the tracheal side via high-speed photography or video recording combined with stroboscopic illumination. Tattooed marks on the lower surface of the vocal fold were used to locate the MU. Pliability was defined as the maximal distance elevated in response to a constant focal negative pressure. RESULTS: Pliability decreased significantly (P=.05) when the vocal fold was lengthened. The point of minimal pliability and MU without vocal fold lengthening were located slightly above the area where the muscular layer approached the epithelial layer. They were located closer to the free edge of the vocal fold when it was lengthened than when it was not. Discrepancy of their locations when the vocal fold was lengthened was suggested. CONCLUSIONS: The MU occurs around the point of minimal pliability when the vocal fold is not lengthened, whereas the MU occurs slightly more laterally than the point of minimal pliability when the vocal fold is lengthened. Although further study is necessary to explain this discrepancy, the presence of the sparse deep layer of the lamina propria seems to be essential in the generation of the mucosal wave.
Animals↗
Fetal behavior assessed in all three trimesters of normal pregnancy by four-dimensional ultrasonography.
AIM: To assess fetal behavior in all three trimesters of normal pregnancy and to investigate the continuation of behavior from fetal to neonatal period. METHODS: One hundred out of 130 pregnant women in all trimesters with singleton pregnancy were assigned for the investigation. All recordings were performed in the morning, after two hours of fasting. Video recordings of newborns were made while the newborns were in bed, separated from other infants in the nursery, dressed, and lying on their backs in a supine position with unrestrained hands. Recording was not performed during prolonged episodes of fussing and crying, during drowsiness, and episodes of hiccupping. All observed facial expressions and movement patterns were presented collectively with maximum, minimum, and median frequencies during 30-minute observation period. RESULTS: We noted a tendency towards decreased frequency of facial expressions and movement patterns with increasing gestational age. In the first trimester, we observed the highest incidence of general movements ranging between 5 and 147, and with a median value of 47. In the second trimester, the number of head and hand movements decreased gradually, compared with the first trimester. The highest range was registered for head retroflexion pattern, ranging from 15 to 42 with a median of 25. The most frequent facial pattern in the second trimester was sucking (3 and 30 movements per infant with a median value of 9). Wilcoxon rank-sum test showed statistically significant differences between the fetuses in the third trimester and the newborns (P<0.05) in hand to head, hand to mouth, hand to eye, hand to ear movement), tongue expulsion, and smiling, whereas the differences between the rest of the movements were not statistically significant. Spearman rank order correlation reached statistical significance (P<0.05) in isolated eye blinking, smiling, grimacing, hand to head, hand to mouth, hand to eye, hand to face, and in hand to ear movement, whereas the differences between the rest of the facial expressions were not statistically significant. CONCLUSION: Fetal behavioral patterns directly reflect the developmental and maturational processes of the central nervous system. 4D observation of fetal and early neonatal period may add to better understanding of the neurological development of the fetus.
Echocardiography, Four-Dimensional↗
Motor patterns and kinematics during backward walking in the pacific giant salamander: evidence for novel motor output.
Kinematic and motor patterns during forward and backward walking in the salamander Dicamptodon tenebrosus were compared to determine whether the differences seen in mammals also apply to a lower vertebrate with sprawling posture and to measure the flexibility of motor output by tetrapod central pattern generators. During treadmill locomotion, electromyograms (EMGs) were recorded from hindlimb muscles of Dicamptodon while simultaneous high-speed video records documented movement of the body, thigh, and crus and allowed EMGs to be synchronized to limb movements. In forward locomotion, the trunk was lifted above the treadmill surface. The pelvic girdle and trunk underwent smooth side-to-side oscillations throughout the stride. At the beginning of the stance phase, the femur was protracted and the knee joint extended. The knee joint initially flexed in early stance and then extended as the foot pushed off in late stance, reaching maximum extension just before foot lift-off. The femur retracted steadily throughout the stance. In the swing phase, the femur rapidly protracted, and the leg was brought forward in an "overhand crawl" motion. In backward walking, the body frequently remained in contact with the treadmill surface. The pelvic girdle, trunk, and femur remained relatively still during stance phase, and most motion occurred at the knee joint. The knee joint extended throughout most of stance, as the body moved back, away from the stationary foot. The knee flexed during swing. Four of five angles showed significantly smaller ranges in backward than in forward walking. EMGs of forward walking showed that ventral muscles were coactive, beginning activity just before foot touchdown and ceasing during the middle of stance phase. Dorsal muscles were active primarily during swing. Backward locomotion showed a different pattern; all muscles except one showed primary activity during the swing phase. This pattern of muscle synergy in backward walking never was seen in forward locomotion. Also, several muscles demonstrated lower burst rectified integrated areas (RIA) or durations during backward locomotion. Multivariate statistical analysis of EMG onset and RIA completely separated forward and backward walking along the first principal component, based on higher RIAs, longer durations of muscle activity, and greater synergy between ventral muscles during early stance in forward walking. Backward walking in Dicamptodon uses a novel motor pattern not seen during forward walking in salamanders or during any other locomotor activity in previously studied tetrapods. The central neuronal mechanisms mediating locomotion in this primitive tetrapod are thus capable of considerable plasticity.
Analysis of Variance↗
Pupillary examination with infrared consumer videocamera.
BACKGROUND: Pupillary observation in the dark is always a problem in a general ophthalmological practice or an outpatient clinic without specialized equipment. We present two methods for observation of the pupils in darkness: 1) illumination of the pupils with the skiascope as a routine examination and 2) infrared observation of the pupils with a consumer digital video camera. METHODS: (1) Pupillary reactions are observed with the skiascope/retinoscope, the observation beam of the device focused to infinity and documented with a video camera. (2) Infrared observation of the pupils was performed with a digital consumer video camera, allowing observation of the pupillary reaction in darkness. After recording, video sequences of interest were transferred to a personal computer and the still images of interest extracted. RESULTS: In everyday clinical routine, observation of the pupillary reaction with the skiascope/retinoscope proves as a reliable tool with a large bandwidth of illumination and a high contrast between pupil and surrounding area. The infrared video camera allows an excellent visualization of the pupillary reflex in darkness. The transfer of the video sequences to a personal computer proved to be simple and single images can easily be chosen. CONCLUSION: Observation of the pupillary reflex with the skiascope proved a useful tool that is available in practically every ophthalmological office. Use of the infrared digital consumer video camera (available at low prices) is a highly sophisticated tool for observation and documentation of pupillary reflex in darkness.
Dark Adaptation↗
Morphologic demonstration of adrenergic influences on the glomerulus.
Previous micropuncture studies found that increasing the adrenergic nerve activity to the kidneys elevates the pre- and postglomerular arteriolar resistances and decreases the glomerular capillary ultrafiltration coefficient (product of the filtration surface area and the hydraulic conductivity to water). To define the morphologic expression of this adrenergic effect on the glomerular capillaries the authors compared the microscopic vascular casts of entire glomeruli from right and left kidneys that were simultaneously perfusion-fixed during selective stimulation of only the left renal nerves. The maximum cross-sectional diameter of ten randomly chosen glomeruli from each stimulated and contralateral kidneys of eight rats averaged 123.7 +/- 4.1 mu in stimulated kidneys compared with a maximum diameter of 136.3 +/- 6.4 in the contralateral kidneys (P less than 0.001). The average perpendicular diameter of 100.4 +/- 1.5 mu in the stimulated kidneys was also significantly smaller than the average diameter of 110.7 +/- 1.9 mu in the contralateral kidneys (P less than 0.005). To examine if morphologic changes analogous to those found in whole glomeruli can be demonstrated at the single cell level, the authors assessed the size of mesangial cells in vitro before, during, and after exposure to the adrenergic neurotransmitter, norepinephrine. First passage mesangial cells approximately 4 weeks after explantation were studied by phase-contrast microscopy and recorded on time-lapse video recorder. The planar surface area of individual mesangial cells was measured by electronic planimeter from photographs of the video images. In response to norepinephrine (1 microM), the surface area decreased significantly on average, from 3.58 +/- 0.28 X 10(-6) sq mm to 3.38 +/- 0.27 (P less than 0.005). Washout of norepinephrine and replacement with hormone-free media in other cells led an increase in the surface area (from 2.47 +/- 0.43 X 10(-6) sq mm to 2.61 +/- 0.40, P less than 0.005). No changes were observed in cells initially bathed in hormone-free media. Thus, the morphologic equivalent of the adrenergic nerve-induced reduction in the ultrafiltration coefficient is a contraction of the glomerular corpuscle. By regulating the configuration of mesangial cells that anchor the glomerular capillary network to the vascular pole, the adrenergic nerve may concurrently determine the number of capillary channels available for filtration as well as the glomerular corpuscular volume.
Adrenergic Fibers↗
[A method for long-term electroencephalographic monitoring in the diagnosis of pseudoseizures].
Fifty-eight patients with psychogenic attacks were studied using continuous monitoring for 3-24 hours. A total of 81 attacks lasting from 5 to 30 min were recorded. The diagnostic value of long-distance, outpatient cassette EEG and video recorder monitoring is undoubted, since it creates the opportunity of simultaneous registration of electroclinical manifestations of paroxysmal and interparoxysmal conditions. The data obtained have shown that the differential diagnosis should be based on the complex of all clinical and electrographic manifestations.
Adolescent↗
Age-related differences in 100-m sprint performance in male and female master runners.
PURPOSE: This study was undertaken to investigate age-related differences in the velocity and selected stride parameters in male and female master sprinters and to determine which stride characteristics were related to the overall decline in the performance of the 100 m with age. METHODS: The performances of 70 finalists (males 40-88 yr, females 35-87 yr) at the European Veterans Athletics Championships were recorded using two high-speed cameras (200 Hz) with a panning video technique and distance markers at 10-m intervals. Velocity, stride length (SL), stride rate (SR), ground contact time (CT), and flight time (FT) during the acceleration, peak velocity, and deceleration phases of the 100-m race were determined from the video records with the aid of the Peak Performance analysis system. RESULTS: There was a general decline in sprint performances with age, the decrease becoming more evident around 65-70 yr of age. The velocity during the different phases of the run declined on average from 5 to 6% per decade in males and from 5 to 7% per decade in females. Similarly, SL showed clear reductions with increasing age, whereas SR remained unchanged until the oldest age groups in both genders. Furthermore, the CT, which correlated with velocity, was significantly longer, and FT, which correlated with both velocity and SL, was shorter in older age groups. CONCLUSION: Our findings indicated that age-associated differences in velocity in elite master sprinters were similar in each phase of the 100-m run. The deterioration of the overall performance with age was primarily related to reduction in SL and increase in CT.
Acceleration↗
Objective assessment of technical skills in cardiac surgery.
OBJECTIVE: Reduced training time combined with no rigorous assessment for technical skills makes it difficult for trainees to monitor their competence. We have developed an objective bench-top assessment of technical skills at a level commensurate with a junior registrar in cardiac surgery. METHODS: Forty cardiothoracic surgeons were recruited for the study, consisting of 12 junior trainees (year 1-3), 15 senior trainees (year 4-6) and 13 consultants. The assessment consisted of four key tasks on standardised bench-top models: aortic root cannulation, vein-graft to aorta anastomosis, vein-graft to Left Anterior Descending (LAD) anastomosis and femoral triangle dissection. An expert surgeon was present at each station to provide passive assistance and rate performance on a validated global rating scale giving rise to a total possible score of 40. Three expert surgeons repeated the ratings retrospectively, using blinded video recordings. Data analysis employed non-parametric tests. RESULTS: Both live and video scores differentiated significantly between performances of all groups of surgeons for all four stations (P < 0.01) (median live and video score for LAD; Junior 19,17; Senior 29,22; Consultant 36,28). Correlations between live and blinded rating were high (r = 0.67-0.84; P < 0.001) as was inter-rater reliability between the three expert video raters (alpha = 0.81). CONCLUSIONS: The use of bench-top tasks to differentiate between cardiac surgeons of differing technical abilities has been validated for the first time. Furthermore, it is unnecessary to perform post-hoc video rating to obtain objective data. These measures can provide formative feedback for surgeons-in-training and lead to the development of a competency-based technical skills curriculum.
Cardiac Surgical Procedures↗