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PubMed2003

The Asymptomatic Carotid Stenosis and Risk of Stroke (ACSRS) study. Aims and results of quality control.

AIM: The results of the Asymptomatic Carotid Atherosclerosis Study (ACAS) study have provided the first scientific evidence that in patients with asymptomatic carotid stenosis greater than 60% carotid endarterectomy reduces the risk of stroke from 2% to 1% per year. The implications are that approximately 20 operations need to be performed in order to prevent 1 stroke in 5 years. The aims of the Asymptomatic Carotid Stenosis and Risk of Stroke (ACSRS) study are to identify a subgroup or subgroups at a risk for stroke higher than 4% and a group at a risk for stroke less than 1% per year using systemic and local risk factors (plaque characterization) in addition to the degree of stenosis. The aim of this paper is to present the protocol and the results of the quality control. METHODS: The ACSRS is a multicentre natural history study of patients with asymptomatic internal carotid diameter stenosis greater than 50% in relation to the bulb. The degree of stenosis is graded using multiple established ultrasonic duplex criteria. In addition, ultrasonic plaque characterization is performed and clinical risk factors and medications are recorded. Training is provided centrally. All carotid ultrasound examinations are recorded on video-tape which together with CT-brain scans and ECG are analysed at the coordinating centre with feedback information to partner centres. RESULTS: The video recordings and analysis of data centrally with feed back information have provided quality control with a significant improvement not only in the completion of data forms but also in the grading of internal carotid stenosis and plaque recordings using ultrasound. CONCLUSION: The high level of quality of data collected will add credibility to the results of the ACSRS study and may eventually promote the development of international standards of plaque imaging and characterization.

Carotid Artery, Internal↗

PubMed2005

Design and implementation of an end tidal CO2 simulator for the evaluation of clinical gas analysers.

This paper presents a new technique to determine the dynamic and frequency response of capnographs using a custom built 'EtCO2 simulator system'. Capnographs are devices that use CO2 from a patients' expired breath to monitor the cardiopulmonary status during anaesthesia and mechanical ventilation. Capnographs at present are routinely calibrated via a static calibration method only. The dynamic response of the capnographs is not accounted for. The frequency and time response are important as they determine if capnographs can be used in high frequency and pediatric ventilation schemes. Experiments performed using the method described in this paper proved that old capnographs usually do not satisfy the manufacturer quoted specifications for time and frequency response. Therefore, a routine check for capnographs is recommended. The method can also be used to verify manufacturer quoted specifications. The EtCO2 simulator system, designed and constructed simulates human respiration cycle. The gas sources used are 5% CO2 and room air that can be switched alternatively. Both supplies are pressure regulated and connected through non-return valves to electric valves. The valves are microprocessor controlled and the on/off time is user defined allowing a wide range of waveforms to be simulated. The output from the simulator is delivered to capnograph. Capnograms are captured by digital video recording. The captured video in 'avi' file format is then converted into individual frames. These frames are converted into digital data through image processing in Matlab. The data obtained is subjected to extensive analysis to determine the frequency and time response of the respective capnograph.

Calibration↗

PubMed1993

Pediatric fiberoptic video bronchoscopy: the use of computer interfacing.

Conventional video-recordings of pediatric bronchoscopic procedures are routinely performed in many centers. The limitations of conventional video-recordings include an inability to concurrently compare serially recorded images, lack of color fidelity of the displayed image, difficulty in image retrieval of archived video, and the inability to subject the image to mathematical analysis. We describe a computer interface which addresses each of these limitations.

Bronchoscopes↗

PubMed1983

Quantification of characteristic blood-flow parameters in the vessels of the retina with a picture analysis system for video-fluorescence angiograms: initial findings.

Fluorescence angiograms of the retina were performed on 12 healthy, adult subjects between the ages of 20 and 52 years with a 30 degrees fundus camera (C. Zeiss), a low-light TV camera and a video recorder. Characteristic blood-flow parameters for the retina were obtained from the video recording using the picture-analysis system (Mikrovideomat 3, C. Zeiss). These included: the arm-retina time (ART), the arteriovenous passage time (AVP) and the arterial contrast-medium velocity (ACMV). Normal values for these parameters were derived for the four retinal quadrants and then discussed. In addition, the filling characteristics of venules were measured and discussed.

Adult↗

PubMed1989

[Facial expression of the vertical dimension before and after orthognathic surgery].

The dynamic analysis of faces of the patients asking for a restoration for an aesthetic injury with a combined orthodontical-surgical treatment requires, besides a static morphological study: with photographs an cephalometric tracings; the study of their facial expression. In order to find out a method of classification of the units of expressive facial behavior, the mobility of the face is studied through the coding of the facial activity by P. EKMAN and W. FRIESEN i.e. the F.A.C.S.: Facial Action Coding System: From the video-recordings of faces and their photographic versions obtained after a pause on the video recorder, these authors have improvised a technic based on the visual observation of the anatomical basis of the movement in connection with facial expression and their description through minimal anatomical action units or A.U. These minimal units of behaviour combine to form mimics. Thanks to the F.A.C.S., the facial mimic of 18 patients before and after orthognatic surgery, and of six samples without dentofacial deformations has been studied. 18,844 AU have been observed, among 6,278 mimics made all together, with 604 different types. A classification of the mimics made by everyone and repeated in time has enabled us to establish a king of "norm" related to expression, allowing us some comparisons with expression of deformed patients. On one hand, for all of the patients examined, we have observed the mimics of the patients after surgery were more identical to the mimics of the samples. On the other hand, some differences have been distinguished concerning the changes of expressivity after surgery depending on the type of morphology before surgery: thus, rather a normal activity of the shrinking of the orbicularis oris has been observed, as well as the buccinator, among the open bites that had been operated on; and the activity of the uppe lip deriving from the "levator Labu Superious Caput infra orbitalis" has become more normal, and rather a normal activity of the lower lip deriving from mentalis, among the operated deep-bites. These results are akin to the clinical observations and suggest that the F.A.C.S. will be able to provide a coding for the study of facial expression.

Emotions↗

PubMedDate not supplied

[A pilot study on training and information of workers exposed to biomechanical overload of the upper limb].

Health education (HE) is very important in the prevention of occupational diseases, particularly when exposure to risk factors can be reduced through working procedures and hygienic behaviours. This pilot study refers to a HE program for prevention of work related muscle-skeletal disorders of upper limbs, carried out in two groups of 15 and 12 workers, respectively employed in trimming and assembling of plastic and metal parts. The first phase of the program consisted of worksite inspections and video recording of working procedures, characteristics of tools and machinery. This was followed by an informative meeting with the workers, which began with the administration of a multiple choice questionnaire, designed to evaluate the baseline knowledge about risk factors, work related muscle-skeletal disorders of upper limbs, working specific procedures and preventive actions. Questionnaires and video recording were repeated after two months in the second phase of the program, as subjective and objective methods of evaluation of HE effectiveness. In both groups, the questionnaire score was significantly increased after the program and a clear improvement was shown in the correct working procedures. This HE program contributed to increase the level of knowledge of the workers and fostered the adoption of working behaviours suitable to reduce the strain for the upper limbs.

Adult↗

PubMed2002

A new method for digital video documentation in surgical procedures and minimally invasive surgery.

BACKGROUND: Documentation of surgical procedures is limited to the accuracy of description, which depends on the vocabulary and the descriptive prowess of the surgeon. Even analog video recording could not solve the problem of documentation satisfactorily due to the abundance of recorded material. By capturing the video digitally, most problems are solved in the circumstances described in this article. METHODS: We developed a cheap and useful digital video capturing system that consists of conventional computer components. Video images and clips can be captured intraoperatively and are immediately available. The system is a commercial personal computer specially configured for digital video capturing and is connected by wire to the video tower. Filming was done with a conventional endoscopic video camera. A total of 65 open and endoscopic procedures were documented in an orthopedic and a thoracic surgery unit. The median number of clips per surgical procedure was 6 (range, 1-17), and the median storage volume was 49 MB (range, 3-360 MB) in compressed form. The median duration of a video clip was 4 min 25 s (range, 45 s to 21 min). Median time for editing a video clip was 12 min for an advanced user (including cutting, title for the movie, and compression). The quality of the clips renders them suitable for presentations. CONCLUSION: This digital video documentation system allows easy capturing of intraoperative video sequences in high quality. All possibilities of documentation can be performed. With the use of an endoscopic video camera, no compromises with respect to sterility and surgical elbowroom are necessary. The cost is much lower than commercially available systems, and setting changes can be performed easily without trained specialists.

Documentation↗

PubMed2006

Interobserver variability of the 5-minute Apgar score.

OBJECTIVES: To assess interobserver variability of Apgar scores assigned with video recordings of neonatal resuscitation (AS(video)) and compare the scores assigned by observers of videos to the Apgar score given by staff attending the delivery (AS(del)). STUDY DESIGN: Ten-second clips of 30 newborns taken at 5 minutes were shown to observers. Infants were 23 to 40 weeks' gestation, received varying degrees of resuscitation, and were monitored with pulse oximetry. Forty-two observers (neonatal/obstetric medical/nursing staff) scored infants' respiratory effort, muscle tone, reflex irritability, and color. The value for heart rate was assigned from the oximeter, which was masked in all clips. All 42 AS(video) and the AS(del) were represented graphically for each infant. Interobserver reliability was assessed by use of a variance components model. RESULTS: AS(video) varied widely between observers. Variability was large for all 4 elements of the score observers assigned and was seen irrespective of the infant's level of illness. AS(del) was greater than AS(video) in most cases, on average by 2.4 points. There was no evidence that the level of discrepancy was substantially different between groupings of staff. CONCLUSION: The Apgar score has poor interobserver reliability. More objective and precise measures of newborns' condition are required.

Apgar Score↗

PubMed2001

The effect of partial removal of the nucleus pulposus from the intervertebral disc on the response of the human annulus fibrosus to compression.

OBJECTIVE: To determine how partial removal of the nucleus changes the response of the annulus to compression. DESIGN: The deformation of the annulus in the mid-sagittal plane, during compression, was determined from digital video images. BACKGROUND: Several studies have shown that removal of the nucleus changes the external behaviour of the intervertebral disc, but few studies have investigated changes to internal behaviour. METHODS: Six frozen human lumbar discs were bisected in the sagittal plane to produce 12 specimens. The cut surfaces were marked with seven dots of Alcian blue stain. The specimens were sealed, enabling their internal structure to be viewed directly by a digital video recording system, and thawed. The video system recorded the response of each specimen as it was compressed by up to 1.8 mm at a rate of 0.2 mm s(-1). The displacements of the Alcian blue marks were measured using an image analysis program. Magnetic resonance imaging was used to investigate the validity of this technique. RESULTS: Partial removal of the nucleus changed the way that the disc deformed under compression. A highly significant change in direction of movement was seen in the inner posterior region of the annulus. CONCLUSIONS: Partial removal of the nucleus changes the response of the annulus to compression. RELEVANCE: Partial denucleation of the human intervertebral disc is shown to change the direction of bulging of the inner annulus when the disc is compressed. Increases in shear stress, arising from these changes, may lead to further disc degeneration in the form of circumferential tears.

Biomechanical Phenomena↗

PubMed2001

A videographic analysis of laryngeal exposure comparing the articulating laryngoscope and external laryngeal manipulation.

Activation of the articulating laryngoscope and external laryngeal manipulation (ELM) improve laryngeal exposure during direct laryngoscopy. We used a head-mounted direct laryngoscopy imaging system and a previously validated scoring system for assessing laryngeal view (the percentage of glottic opening or POGO score) on 33 adult patients undergoing laryngoscopy. On each patient, we videotaped the initial laryngeal exposure (blade not activated), the view with activation of the blade, and the view with operator-directed external laryngeal manipulation. The video recordings were reviewed and the laryngeal view assessed with POGO scores. POGO scores improved with blade activation in 9/33 (27%) of patients vs 28/33 (85%) of patients with ELM. In nearly half of patients studied (16/33, 48%) POGO scores decreased with blade activation. We conclude that ELM is superior to articulating laryngoscope blade activation in improving POGO scores during laryngoscopy on adult patients in standard sniffing position. Using recordings from a direct laryngoscopy video system, we compared laryngeal views in 33 patients with a special articulating laryngoscope blade to views achieved by external laryngeal manipulation (pressing on the patient's neck). Laryngeal exposure, which is important for placement of tracheal tubes, was better with external laryngeal manipulation.

Adult↗

PubMed1995

Cognitive computer-based video analysis: its application in assessing the usability of medical systems.

This paper describes a methodology, based on cognitive research, for assessing the usability of medical computing systems. The issue of developing appropriate evaluation tools, both for use in the design process and for analysis of end products, is beginning to be recognized as being of great importance. In this paper, the use of video recording for collecting empirical data on system usability is detailed. The techniques described allow for the collection of an integrated data set consisting of the transcripts of physicians as they "think aloud" in interacting with a medical system, along with video records of user-computer interaction. The use of coding methodologies and a computer-based annotation system for the analysis of video data are described. Our preliminary experience indicates that this methodology offers a powerful way for assessing physicians' informational needs. Implications for the development and evaluation of medical information systems are discussed.

Computer Systems↗

PubMed1987

Retinal axons with and without their somata, growing to and arborizing in the tectum of Xenopus embryos: a time-lapse video study of single fibres in vivo.

Time-lapse video recordings were made of individual retinal ganglion cell fibres growing to and terminating in the optic tectum of Xenopus embryos. The fibres were stained by inserting a crystal of the lipophilic fluorescent dye, DiI, into the developing retina. Growth cones were observed in the optic tract and tectum using 20 ms flashes of light to induce fluorescence approximately once every minute. Fluorescent images were captured with a SIT camera, processed and saved on a time-lapse video recorder. The main conclusions from observing normal growing fibres are as follows. (1) Axons in the optic tract grow at a steady rate directly toward their targets without retracting or branching. (2) As axons approach the tectum they slow down and their growth cones become more complex. (3) Most terminal branches in the tectum are formed by back branching rather than by bifurcation of leading growth cones. In a second experiment, labelled growing axons were separated from their cell bodies by removing the retina. Such isolated axons continued to grow for up to 3 h in vivo and were capable of recognizing the tectum and arborizing there. This result shows that growth cones must contain the machinery needed to sense and respond to their specific pathways and targets.

Animals↗

PubMed1997

Correlation of the endoscopic and radiological anatomy of congenital obstruction of the posterior urethra and the external sphincter.

OBJECTIVE: To determine whether the external sphincter is distal to congenital occlusion of the posterior urethra in boys by correlating endoscopic video-recorded information with cysto-urethrographic observations and assessing the anatomy of the disease. PATIENTS AND METHODS: This study reviewed the endoscopic and radiographic findings in 42 boys (mean age 42 months, range newborn to 14 years), using material from a videotape library, and correlated these with the pre-operative cystogram. The nature of the obstructive lesion and its relationship to the verumontanum and the external sphincter was assessed. RESULTS: Of the 42 boys, 36 had the proximal extent of the external sphincter identified on the endoscopic video recording to be above the posterior urethral membrane; 22 of the membranes were obstructive. The proximal extent of the external sphincter was identified on the static cystogram images of only 31 of the 38 boys examined, but only ever above the posterior urethral membrane. CONCLUSION: The proximal extent of the external sphincter, i.e. that portion which is most prominent endoscopically, is proximal to the membrane in congenital obstruction of the posterior urethra.

Adolescent↗

PubMed2003

Distinct forelimb and hind limb stepping impairments in unilateral dopamine-depleted rats: use of the rotorod as a method for the qualitative analysis of skilled walking.

The rotorod test, in which animals walk on a rotating drum, is widely used to assess motor status in laboratory rodents. Performance is measured by the duration that an animal stays up on the drum as a function of drum speed. Here we report that the task provides a rich source of information about qualitative aspects of walking movements. Because movements are performed in a fixed location, they can readily be examined using high-speed video recording methods. The present study was undertaken to examine the potential of the rotorod to reveal qualitative changes in the walking movements of hemi-Parkinson analogue rats, produced by injection of 6-hydroxydopamine (6-OHDA) into the nigrostriatal bundle to deplete nigrostriatal dopamine (DA). Beginning on the day following surgery and then periodically over the next two months, the rats were filmed from frontal, lateral, and posterior views as they walked on the rotorod. Behavior was analyzed by frame-by-frame replay of the video records. Rating scales of stepping behavior indicated that the hemi-Parkinson rats were chronically impaired in their posture and in the use of the limbs contralateral to the DA-depletion. The contralateral limbs not only displayed postural and movement abnormalities, they participated less in initiating and sustaining propulsion than did the ipsilateral limbs. These findings not only reveal new deficits secondary to unilateral DA-depletion, but also show that the rotorod can provide a robust tool for the qualitative analysis of movement.

Animals↗

PubMed2003

Tarsal movements in flies during leg attachment and detachment on a smooth substrate.

In order to understand the attachment mechanism of flies, it is important to clarify the question of how the adhesive pad (pulvillus) builds and breaks the contact with the substrate. By using normal and high-speed video recordings, the present study revealed that pulvilli are positioned on the surface in a particular way. The pulvilli are apparently loaded or pressed upon the substrate after leg contact, as evidenced by splaying of the claws. Detachment of pulvilli from the substrate may be achieved in four different modes depending on the leg (fore-, mid- or hindleg): pulling, shifting, twisting, and lifting. Lifting is the only detachment mode depending on the claws' action. Kinematics of the tarsal chain is studied in leg preparations, in which the tendon of the claw flexor muscle was pulled by tweezers and video recorded. The morphological background of tarsal movements during attachment and detachment is studied by scanning electron microscopy, fluorescent microscopy, and bright field light microscopy followed by serial semithin sectioning of pretarsal structures. Several resilin-bearing springs are involved in the recoil of the tarsal segments to their initial position, when the tendon is released after pull.

Animals↗

PubMed2006

Use of concurrent and retrospective verbal protocols to investigate workers' thoughts during a manual-handling task.

A manual handling task (an order picking task in a distribution warehouse) was investigated using concurrent verbal protocols and retrospective verbal protocols (applied at three different times after completion of the task). The study aimed to collect workers' thoughts during the task and to determine what workers are comfortable with reporting. Video recordings of the task were used as a means of investigating the accuracy of the information which was reported. The concurrent and retrospective verbal protocol methods were compared and it was found that concurrent reports could be used to collect a range of task related thoughts, although they only contained a proportion of the workers' thoughts during the task. Additional information could be obtained from retrospective reports, although these appeared to be vulnerable to bias and re-ordering of reported information. The retrospective reports produced whilst watching a video recording of the task were particularly vulnerable to bias from retrospective reasoning or the rationalisation of thoughts. Only one specific reference to posture or handling technique was made by any of the workers in their reports. There were also few references to load characteristics. Workers frequently reported aspects of the task that were easier to verbalise, such as the counting or labelling of items. It is not known whether the workers were only aware of these limited details of their tasks or whether they were only able to report limited details of the tasks because of factors affecting verbal reporting. This was an exploratory study which has collected valuable information from a small sample of experienced workers in relation to a common task from industry, but further study is needed to investigate the effects of factors such as load weight, load position and task duration on awareness and reporting of thoughts.

Adult↗

PubMed2001

[Assessment of general movements at routine medical examination of one-month-old infants].

On routine medical examination of one-month-old infants, general movements (GMs) were video-recorded for about 5 minutes of 252 infants born at Kyoto City Hospital or other hospitals, including the infants discharged from the NICU. Their ages ranged from 39 postmenstrual to 8 post-term weeks. One of the experimenters assessed 181 infants among 252 available for assessment of their GMs twice at intervals of more than one month without being informed about their clinical histories. The subjects included 19 low-birthweight infants, and their average age was 3.5 post-term weeks. The assessment was carried out in comparison to the "gold standard" GMs depicted in a demonstration video produced by the GMs Trust. The Kappa value for intra-observer concordance was 0.85. Twenty (11.0%) out of the 181 infants were judged abnormal because of their poor repertoire of GMs in both the first and second assessment. Neither cramped synchronized GMs nor chaotic ones were observed. Meanwhile, 155 (85.6%) out of the 181 infants were found to be normal. The incidence of abnormal GMs was significantly higher among infants with history of asphyxia and/or respiratory distress than among low-risk infants. There of the experimenters independently assessed GMs of 50 infants among 181 which had been video-recorded between June and September 1998. The inter-observer concordance was higher among the low-birth weight infants than among full-term ones. In conclusion, qualitative assessment of GMs by an experienced observer at routine medical examination of one-month old infants is a useful method for the follow-up of high-risk infants.

Female↗

PubMed1993

Differential effects of brain lesions and systemic disease on the quality of general movements: a preliminary report.

Assessment of the quality of general movements in preterm infants by means of 1-h video recordings is a sensitive method for investigating the integrity of the central nervous system. In two preterm infants, who were followed weekly until term, an abnormal quality of general movements was found, presumably due to systemic disease (bacterial and fungal infections). Both children were neurologically normal at the age of 6 (case A) and 12 months (case B) corrected age. In contrast to abnormal general movements due to a brain lesion, the abnormal quality of general movements in systemic disease is not consistently observable, not even during the 1 h of video recording. The presence, in otherwise abnormal general movements, of remaining rotations, superimposed on flexion and extension of the limbs, appears to be a reliable indication for a favourable outcome. Another abnormality seen in one of the infants was a severe reduction in the number of general movements, but with a normal quality in the remaining few general movements. This indicates that a reduction in quantity of general movements is prognostically not a bad sign, at least not if the quality of the remaining movements is normal. Although the underlying pathophysiologic mechanisms remain unclear, these findings are important in clinical practice. It means that it is possible to discriminate between abnormal general movements due to a cerebral lesion, and abnormal general movements due to systemic disease (infection), provided that the observation period is sufficiently long and a longitudinal developmental trajectory is obtained.

Bacterial Infections↗