PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Video Recording”

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

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

At least 469 records · Page 26Linked to original sources
PubMed2000

Amphetamine-induced activation of forebrain EEG is prevented by noradrenergic beta-receptor blockade in the halothane-anesthetized rat.

RATIONALE: Amphetamine (AMPH)-like stimulants represent an intensively studied class of psychoactive drugs. Despite the well-known and potent arousal-enhancing effects of these drugs, the neurobiological substrates of AMPH-induced arousal have rarely been examined explicitly. Activity of the locus coeruleus-noradrenergic system is causally and positively related to behavioral and electroencephalographic (EEG) indices of arousal. For example, activation of locus coeruleus neurons or stimulation of medial basal forebrain noradrenergic beta-receptors elicits activation of forebrain EEG in the anesthetized rat. Further, stimulation of noradrenergic beta-receptors within the medial basal forebrain elicits a substantial increase in alert, active waking. These and other observations suggest that at least some of the arousal-enhancing actions of AMPH-like stimulants derive from AMPH-induced increases in noradrenergic neurotransmission at beta-receptors. The current study examines the extent to which AMPH-induced activation of cortical EEG is dependent on actions of central beta-receptors. METHODS: The effects of intracerebroventricular (ICV; 2 microl) pretreatment with either vehicle (artificial extracellular fluid) or the beta-antagonist, timolol (25, 50 or 100 microg), on the cortical EEG activating effects of intravenous AMPH (0.15 mg/kg) were examined in the halothane-anesthetized rat. EEG was recorded on polygraph and video recording tape and later analyzed using power spectral analyses (PSA). AMPH-induced alteration in cortical EEG activity was measured using PSA in vehicle- and timolol-pretreated animals. RESULTS: Neither vehicle nor timolol ICV infusions altered cortical EEG activity patterns. In vehicle-pretreated animals, AMPH elicited a robust activation of cortical EEG, characterized by the substantial decrease in large-amplitude, slow-wave activity. Timolol pretreatment dose-dependently prevented AMPH-induced cortical EEG activation. This effect of timolol was statistically significant at the 50 microg and 100 microg dose. CONCLUSIONS: These observations indicate that, under these experimental conditions, AMPH-induced activation of the forebrain is dependent on actions of noradrenergic beta-receptors. Combined with previous observations, these observations support the hypothesis that AMPH-induced increases in arousal involve noradrenergic neurotransmission at beta-receptors.

Amphetamine↗
PubMed1990

Coordination of deglutitive glottic closure with oropharyngeal swallowing.

The goals of this study were to quantify the temporal relationship between swallow-induced glottic closure and (a) signals of swallow initiation, such as hyoid bone movement, tongue base movement, and mylohyoid electrical activity; (b) pharyngeal peristalsis; (c) laryngeal elevation; (d) vestibular closure; and (e) oropharyngeal barium bolus transit. Eight normal subjects (age 20-30 yr) were studied by concurrent transnasal video laryngoscopy, pharyngeal intraluminal manometry, and submental surface electromyography. The manometric, electromyographic, and both video recordings were synchronized with one another using a specially designed event marker. Dry, 5-ml water, and 5-ml barium swallows were recorded. Frame-by-frame analysis of the video endoscopic recordings showed that deglutitive laryngeal kinetics consisted of vocal cord adduction associated with transverse approximation of the arytenoids followed by vertical approximation of arytenoids to the base of the epiglottis followed by laryngeal ascent and epiglottic descent. Onset of swallow-induced vocal cord adduction preceded the onset of hyoid bone movement, base of the tongue movement, and submental surface myoelectric activity by 0.33 +/- 0.04 (SE) s, 0.31 +/- 0.04 s, and 0.38 +/- 0.04 s, respectively. Onset of vocal cord adduction also preceded the initiation of peristalsis in the nasopharynx and its propagation to oropharynx and upper esophageal sphincter by 0.64 +/- 0.05 s, 0.82 +/- 0.05 s, and 1.08 +/- 0.04 s, respectively. The time between the onset of vocal cord adduction and their return to full opening was 2.2 +/- 0.09 s. It was concluded that (a) among events evaluated, vocal cord adduction is the initial event during the swallowing sequence; (b) laryngeal kinetics during deglutition have distinctive features, and their close coordination with other swallowing events suggests that they are an essential feature of the swallowing program; and (c) abnormal laryngeal kinetics or lack of coordination between the glottic closure mechanism and oropharyngeal bolus transport may have an important role in swallow-induced aspiration.

Adult↗
PubMed2006

Temporal window of integration in auditory-visual speech perception.

Forty-three normal hearing participants were tested in two experiments, which focused on temporal coincidence in auditory visual (AV) speech perception. In these experiments, audio recordings of/pa/and/ba/were dubbed onto video recordings of /ba/or/ga/, respectively (ApVk, AbVg), to produce the illusory "fusion" percepts /ta/, or /da/ [McGurk, H., & McDonald, J. (1976). Hearing lips and seeing voices. Nature, 264, 746-747]. In Experiment 1, an identification task using McGurk pairs with asynchronies ranging from -467 ms (auditory lead) to +467 ms was conducted. Fusion responses were prevalent over temporal asynchronies from -30 ms to +170 ms and more robust for audio lags. In Experiment 2, simultaneity judgments for incongruent and congruent audiovisual tokens (AdVd, AtVt) were collected. McGurk pairs were more readily judged as asynchronous than congruent pairs. Characteristics of the temporal window over which simultaneity and fusion responses were maximal were quite similar, suggesting the existence of a 200 ms duration asymmetric bimodal temporal integration window.

Acoustic Stimulation↗
PubMed2004

Skill acquisition and retention in automated external defibrillator (AED) use and CPR by lay responders: a prospective study.

This prospective study evaluated the acquisition and retention of skills in cardio-pulmonary resuscitation (CPR) and the use of the automated external defibrillator (AED) by lay volunteers involved in the Department of Health, England National Defibrillator Programme. One hundred and twelve trainees were tested immediately before and after and initial 4-h class; 76 were similarly reassessed at refresher training 6 months later. A standardised test scenario that required assessment of the casualty, CPR and the use of on AED was evaluated using recording manikin data and video recordings. Before training only 44% of subjects delivered a shock. Afterwards, all did so and the average delay to first shock was reduced by 57 s. All trainees placed the defibrillator electrodes in an "acceptable" position after training, but very few did so in the recommended "ideal" position. After refresher training 80% of subjects used the correct sequence for CPR and shock delivery, yet a third failed to perform adequate safety checks before all shocks. The trainees self-assessed AED competence score was 86 (scale 0-100) after the initial class and their confidence that they would act in a real emergency was rated at a similar level. Initial training improved performance of all CPR skills, although all except compression rate had deteriorated after 6 months. The proportion of subjects able to correctly perform most CPR skill was higher following refresher training that after the initial class. Although this course was judged to be effective in teaching delivery of counter-shocks, the need was identified for more emphasis on positioning of electrodes, pre-shock safety checks, airway opening, ventilation volume, checking for signs of a circulation, hand positioning, and depth and rate of chest compressions.

Adult↗
PubMed1993

Intraoperative transesophageal echocardiography for the detection of cardiac preload changes induced by transfusion and phlebotomy in pediatric patients.

BACKGROUND: Intraoperative blood volume changes are difficult to monitor in pediatric patients. The authors tested the hypothesis that transesophageal echocardiography would identify changes in cardiac filling resulting from manipulations of blood volume. METHODS: Eleven patients (3-15 kg) were studied following sternal closure after repair of congenital heart lesions. Transesophageal echocardiography of the midpapillary left ventricular short axis view and hemodynamics were recorded at baseline (T1), during withdrawal of blood until the systolic blood pressure decreased by 5 mmHg (T2) and 10 mmHg (T3), and after reinfusion of the blood (T4). The identical cycle of blood withdrawal and reinfusion was repeated after administration of calcium chloride (10 mg/kg; T5-T8). RESULTS: Manually traced transesophageal echocardiography images of the left ventricular end-diastolic area decreased from 4.64 +/- 1.50 cm2 at T1 to 4.03 +/- 1.25 cm2 at T2 to 3.78 +/- 1.35 cm2 at T3, and increased to 4.42 +/- 1.75 cm2 at T4. Nearly identical results were obtained at T5-T8. End-systolic areas significantly decreased from 1.96 +/- 0.86 cm2 at T1 to 1.52 +/- 0.73 cm2 at T2 to 1.41 +/- 0.62 cm2 at T3, and increased to 1.87 +/- 0.88 cm2 at T4. An experienced anesthesiologist-echocardiographer blinded to study events was able to identify mild reductions in blood volume (T2, T3, T6, T7) from recorded cine-loop video recordings with high sensitivity (80-95%) and specificity (80%). CONCLUSIONS: Transesophageal echocardiography is a potentially useful monitor of cardiac filling changes in pediatric patients.

Blood Transfusion↗
PubMed1986

Radiology of the nutcracker esophagus.

We prospectively evaluated 22 patients with manometrically proven "nutcracker esophagus" (high amplitude peristaltic contractions). All patients were symptomatic with angina-like chest pain, dysphagia, or both. Patients underwent barium esophagram with video-recording of the images. Video tapes were reviewed independently by a gastrointestinal radiologist who was unaware of the patients' manometric diagnoses. The video-esophagram was normal in 12 of 22 (55%) patients. Eight of 22 (36%) had dysmotility: either diffuse spasm (9%) or tertiary contractions (27%) (Fig. 2). A hiatal hernia was the only abnormality in two patients. Although the presence of diffuse spasm or tertiary contractions may suggest the presence of the underlying motor disorder in patients with nutcracker esophagus, we conclude that the "barium swallow" lacks sufficient sensitivity to screen adequately for this disorder in patients with atypical angina or dysphagia.

Adult↗
PubMedDate not supplied

Effects of 10 min tilt and visual directional information on ocular counterrolling.

The effects of 10 min of static tilt on ocular counterrolling (OCR) were investigated. Seven healthy volunteers were tilted 45 degrees around the naso-occipital axis, fixed at that position for 10 min, and the pre- and post-tilt OCRs were recorded. OCR was video-recorded using an infrared CCD camera and subjected to computer image analysis. The subjects were directed to fixate on an imagined target in the dark (experiment 1), or viewed an earth vertical, striped pattern placed in front of his/her eyes to enhance the recognition of extent of body tilt (experiment 2). In experiment 1, the average OCRs recorded before and after 10 min of tilt showed no significant changes. However, in experiment 2, OCR decreased significantly after 10 min of tilt. These results suggest that visual perception of spatial verticality can produce time-dependent adaptation of OCR.

Adaptation, Ocular↗
PubMed1996

Validating the process of taking lateral foot x-rays.

This study validates the concept that a standard (static) weightbearing lateral x-ray, taken with an orthoposer device, in the patient's angle and base of gait is clinically similar to findings seen during ambulatory (dynamic) gait. Sixty female subjects requiring diagnostic x-rays underwent videofluoroscopy of their walking gait. Using a single-frame, shuttle-advance video recorder, the appropriate fluoroscopic video frame was identified. The calcaneal pitch angle was measured using a digitized program. A high repeatability of the measuring process and high correlation between x-ray and fluoroscopic results suggest the value of taking weightbearing angle and base of gait lateral x-rays.

Adolescent↗