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Effects of vagal stimulation on swimbladder blood flow in the european eel Anguilla anguilla.

The influence of the vagus nerve on swimbladder blood flow in the European eel (Anguilla anguilla) was characterized by recording the changes in blood flow rate and blood pressure following stimulation of the vagus nerve. After electrical stimulation, blood flow in the swimbladder artery increased from 0.9 ml min-1 to 2.1 ml min-1. Video recordings of small vessels on the caudal side of the rete mirabile revealed an increase in erythrocyte velocity combined with a small vasodilation. This effect could not be blocked by injection of the -adrenergic antagonist phentolamine, the ss-adrenergic antagonist propranolol or the muscarinic cholinoceptor antagonist atropine. In all preparations with a high initial flow rate (>1.9 ml min-1), vagotomy resulted in a marked decrease in blood flow (by approximately 80 %). This effect was not observed in preparations with a low initial swimbladder blood flow. Stimulation of the vagus nerve produced a decrease, and vagotomy produced an increase, in perfusion pressure in blood-perfused swimbladder preparations. Histological studies revealed the presence of a ganglion in the vagus nerve located on the anterior part of the resorbing section of the swimbladder close to the origin of the ductus pneumaticus, which is probably associated with swimbladder function. These results suggest that swimbladder blood flow, at least to some extent, is under vagal tonic control. The effects do not, however, appear to involve the classical - and ss-adrenergic or muscarinic cholinoceptor functions.

Air Sacs↗

Ambulatory accelerometry to quantify motor behaviour in patients after failed back surgery: a validation study.

In the treatment of patients with pain, measures related to (pain) behaviour are of major importance. Ambulatory activity monitoring can be used to obtain insight into actual behaviour. This study was designed to validate the Activity Monitor (AM), an instrument based on long-term ambulatory monitoring of accelerometer signals, to assess several physical activities during normal daily life. Ten failed back surgery (FBS) patients performed a number of functional activities in and around their own houses. During the measurements, continuous ambulatory registrations of accelerometer signals were made, based on four body-mounted accelerometers (one on each upper leg, two on the trunk). Video recordings made simultaneously with the measurements were used as a reference. The continuous output of the AM (postures, transitions, dynamic activities) was compared with visual analysis of the videotapes. The overall results showed an agreement between AM output and video analysis of 87% (inter subject range: 83-88%). The maximal error in the determination of the duration of activities was 0.3%. The overall number of dynamic periods was determined well (AM: 359; video: 368), while the number of transitions was slightly overestimated (AM: 228; video: 205). The results when using the three-sensor version of the AM were somewhat less accurate (overall agreement from 87% to 82%). The AM appeared to be a valid instrument to quantify aspects of behaviour of FPS patients, such as duration of activities and number of transitions. This new technique of ambulatory measurement of mobility activities seems to be a relevant and promising extension of the techniques currently used in the evaluation of pain treatment.

Acceleration↗

Validation of rule-based inference of selected independent activities of daily living.

This paper explores the validity of a rule-based inference method of selected independent activities of daily living (ADLs). An inexpensive ADL monitoring system was installed in the community for 37 days to monitor a middle-aged, healthy individual living alone. The subject was given a personal digital assistant (PDA), running custom activity diary software, and asked to record activities in real-time. Rule-based activity inference algorithms were refined on data from 17 days, and data from the remaining 20 days were used for validation. The chisquare statistic was computed for 2 x 2 contingency tables comparing activities detected by the algorithms to user-logged activities. The phi (r()) and Cohen's kappa (kappa) coefficients were computed as measures of correlation. After correcting for subject noncompliance in logging activities, the kappa correlation between the meal detection algorithm and the PDA record was 0.84, with 91% sensitivity, and 100% specificity. Similarly, the kappa correlation between the shower detection algorithm and the PDA record is 0.69, with 67% sensitivity and 100% specificity. The detection algorithms and the sensory data did not miss any main meals or showering activities recorded on the PDA. The results suggest that rule-based algorithms can successfully detect meal preparation and showering activities using simple low-cost detectors. The sensors and detection algorithms reported events not recorded by the occupant on the PDA attributed to reporting noncompliance. Overall, the PDA activity journal was a compromise between paper diaries, which are more time consuming to keep, and may result in higher noncompliance errors, and video recording, which is considered intrusive.

Activities of Daily Living↗

Computer use by general practitioners in Scotland.

BACKGROUND: Despite the widespread adoption by general practitioners (GPs) of desktop computers, there has been very little evaluation of the way in which the computer is actually used during consultations and the way in which it affects patient satisfaction. AIM: To ascertain the extent to which the computer is used in the consultation and to investigate the possible relationship between computer use and patient satisfaction. METHOD: Six GPs completed a short questionnaire about the extent to which they use the computer during surgeries. Eighty-four consultations from the surgeries of these GPs were video recorded. Patient satisfaction data on these 84 patients were collected at the time of the surgery using the previously validated Consultation Satisfaction Questionnaire. RESULTS: All six GPs stated that they usually used the computer during consultations. However, video observation revealed that the computer was used in just 51% of surgeries. The proportion of time that the computer was used for varied from 0.03 to 0.4, with a mean value of 0.12. The commonest function for which the computer was used was prescribing. The consultations in which the computer was used (CU) were on average 148 seconds longer than the non-computerized consultations (NCU). There was no difference in patient satisfaction between the two groups. CONCLUSION: Despite this group of GPs having a self-declared interest in the use of computers, the extent to which the computer was used was much lower than expected from the GPs' self-reported use. This may be partly explained by the fact that using the computer takes up valuable time within the consultation and does not appear to contribute to patient satisfaction. If desktop computers are to be used to their full potential in general practice, more work is required to evaluate their impact on the consultation process itself.

Adolescent↗

Postural, epidemiological and biomechanical analysis of luggage handling in an aircraft luggage compartment.

Loading and unloading of luggage in an aircraft luggage compartment is carried out manually in uncomfortable working position. In this study, the loading work was analysed by surveying musculoskeletal symptoms, by recording the working postures and techniques at work, and by simulating the loading work in a mock-up of a DC-9 aircraft compartment. Low back, knees and shoulders were exposed to mechanical load in luggage handling. Video recordings were used to analyse posture and work technique. In the simulated luggage compartment in the laboratory, ground reaction forces, intra-abdominal pressure (IAP) and electromyography (EMG) signals from back and shoulder muscles were recorded simultaneously. Loading in sitting, squatting and kneeling were the postures that were used the most often. Unloading was generally less stressful than loading, involving less static work. Handling time was shortest when kneeling but knee symptoms were dominant. Lateral ground reaction forces and EMG activity from trapezius were highest when sitting, and IAP peaks were greatest when squatting. Thus each posture had major, though differing, disadvantages and a radical redesign of the DC-9 luggage compartment was clearly indicated.

Journal Article↗

Cisapride decreases gastroesophageal reflux in preterm infants.

OBJECTIVE: Gastrointestinal prokinetic agents, such as cisapride, are commonly used in pediatric practice to improve gastric emptying, to decrease emesis, to improve lower esophageal sphincter tone, and to improve irritability and feeding aversion associated with gastroesophageal reflux (GER). Although cisapride seems to be effective in infants from 2 months to 14 years old, data for younger and preterm infants are not available. Whether reflux is a significant cause of reflex apnea or feeding intolerance in the preterm infant is controversial. The objective of this 1-year prospective study, started in 1998, was to determine the efficacy of cisapride for treatment of reflux and reflux-associated apnea (RAAP) in preterm infants. Before this study, the diagnosis of reflux was often made clinically and the effect of therapy on reflux or the decision to increase the dose of cisapride was made empirically. The clinical bias was that persistent apnea, not responding to caffeine, was caused by GER. We reasoned that a systematic approach to the diagnosis and treatment of reflux would improve the care of preterm infants and reduce the risk of toxicity, especially if an increased dose of cisapride showed no improvement in reflux or apnea. STUDY DESIGN: Twenty-four preterm infants (24-36 weeks' gestational age) had clinical apnea/pH studies when they were referred by the attending neonatologist for suspected GER. These infants were born at 28.8 +/- 3.1 weeks with birth weight of 1169 +/- 387 g (range: 631-2263 g). Each infant was studied before and 8 days after starting cisapride treatment. Cisapride dose was 0.09 to 0.25 mg/kg every 6 hours enterally. Treatment decisions regarding dose of cisapride were the responsibility of the attending neonatologist. The pH was recorded continuously for 24 hours at 0.25 Hz and was analyzed using EsopHogram software. A single sensor pH catheter was inserted to ~2 cm above the esophageal gastric junction. GER was defined as a drop in esophageal pH below 4.0 for a least 5 seconds, or pathologic GER was defined as a reflux index (RI) >2 standard deviation (SD) from the mean based on published norms for term infants. The following parameters were calculated from the pH recording: number of reflux events per 24 hours, duration of the longest episode, number of episodes >5 minutes per 24 hours, and RI, ie, percentage of time with pH <4.0. Each study had a combined time-lapse video recording and multichannel digital recording. Recorded parameters were: continuous pulse oximetry, electrocardiogram, respiratory effort (piezo sensor), and airflow (temperature sensor at nostrils and mouth). The recording was scored for central apneas of 10 to 14 seconds and >/=15 seconds (prolonged) and >/=10 seconds for obstructive and mixed apneas. RAAP was scored when an apnea (irrespective of the type) occurred within 1 minute of a GER event. Baseline, after cisapride, and follow-up electrocardiograms were performed because of concern about prolonged QTc and cardiac arrhythmias. The infants were 35.6 +/- 4.5 weeks postconceptional age when first studied. Twelve infants (mean birth weight: 1821 +/- 749 g; gestational age: 32 +/- 2 weeks; postconceptional age: 35.6 +/- 2.6 weeks) were identified retrospectively as controls because their baseline GER parameters were within the normal range using Vandenplas' criteria. RESULTS: Overall, cisapride treatment significantly improved the RI from 16.6 +/- 15.2 to 9.1 +/- 8.4 SD. The number of reflux episodes >/=5 minutes was reduced from 7.1 +/- 5.8 to 4.3 +/- 4.4 SD. No significant effect was seen on the total number of refluxes (/24 hours). Eight infants (33%) had no decrease in the RI after a week of treatment. Three of these infants improved after cisapride dose was increased from 0.09 to 0.25 mg/kg/dose every 6 hours. Although 0.09 mg/kg/day is the minimum effective dose, 67% of our infants did respond to this low dose. Cisapride was discontinued in 3 infants because of prolonged QTc >/=0.450 seconds (0.473 in 1 and 0.470 in 2). More data about the effect of cisapride on QTc interval are reported in Pediatrics in a separate article. Only 1 infant showed no improvement with increased dose. Caffeine treatment had no effect on the baseline or follow-up GER values. Although apnea indexes for central and obstructive apnea were similar before and after cisapride, mixed apnea was less during treatment. There was a significant decrease (0.32 +/- 0.40 to 0.12 +/- 0.17/hour) in RAAP when the one infant who had increased reflux on increased dose of cisapride was excluded as an outlier. The statistical difference, before and after cisapride, for the group is significant with the outlier omitted. The clinical significance is unclear because ~50% of the infants had minimal changes in their apnea indexes. Furthermore, ~40% of infants did not have RAAP. (ABSTRACT TRUNCATED)

Cisapride↗

Mechanisms of head injuries in elite football.

OBJECTIVES: The aim of this study was to describe, using video analysis, the mechanisms of head injuries and of incidents with a high risk of head injury in elite football. METHODS: Videotapes and injury information were collected prospectively for 313 of the 409 matches played in the Norwegian (2000 season) and Icelandic (1999 and 2000 season) professional leagues. Video recordings of incidents where a player appeared to be hit in the head and the match was consequently interrupted by the referee were analysed and cross referenced with reports of acute time loss injuries from the team medical staff. RESULTS: The video analysis revealed 192 incidents (18.8 per 1000 player hours). Of the 297 acute injuries reported, 17 (6%) were head injuries, which corresponds to an incidence of 1.7 per 1000 player hours (concussion incidence 0.5 per 1000 player hours). The most common playing action was a heading duel with 112 cases (58%). The body part that hit the injured player's head was the elbow/arm/hand in 79 cases (41%), the head in 62 cases (32%), and the foot in 25 cases (13%). In 67 of the elbow/arm/hand impacts, the upper arm of the player causing the incident was at or above shoulder level, and the arm use was considered to be active in 61 incidents (77%) and intentional in 16 incidents (20%). CONCLUSIONS: This study suggests that video analysis provides detailed information about the mechanisms for head injuries in football. The most frequent injury mechanism was elbow to head contact, followed by head to head contact in heading duels. In the majority of the elbow to head incidents, the elbow was used actively at or above shoulder level, and stricter rule enforcement or even changes in the laws of the game concerning elbow use should perhaps be considered, in order to reduce the risk of head injury.

Arm↗

Measuring daily behavior using ambulatory accelerometry: the Activity Monitor.

Advanced ambulatory systems that measure aspects of overt human behavior during normal daily life have become feasible, owing to developments in data recording and sensor technology. One such instrument is the Activity Monitor (AM). This paper provides a technical description of the AM and information about its validity and current applications. The AM is based on ambulatory accelerometry, the aim of which is to assess postures and motions for long-term (> 24-h) measurement periods during normal daily life. Accelerometers are attached to the thighs, trunk, and lower arms, and signals are continuously stored in a digital portable recorder. In the postmeasurement analysis, postures and motions are detected by means of custom-made software programs. Validity studies performed on different populations showed high agreement scores between the computerized and automatic AM output and the visually analyzed video recordings. The AM has so far been applied in rehabilitation, psychophysiology, and cardiology but has many possibilities in behavioral research.

Activities of Daily Living↗

The value of sonography in the detection of bone erosions in patients with rheumatoid arthritis: a comparison with conventional radiography.

OBJECTIVE: The ability to make an early, accurate diagnosis of rheumatoid arthritis (RA) has become increasingly important with the availability of new, expensive, and targeted therapies. However, plain radiography, the traditional method of detecting the characteristic bone erosions and an important adjunct in establishing a diagnosis of RA, is known to be insensitive. This study compared sonography, a modern imaging technique, with conventional radiography for the detection of erosions in the metacarpophalangeal (MCP) joints of patients with RA. METHODS: One hundred RA patients (including 40 with early disease) underwent posteroanterior radiography and sonography of the MCP joints of the dominant hand. Twenty asymptomatic control subjects also underwent sonography. Erosion sites were recorded and subsequently compared using each modality. Magnetic resonance imaging (MRI) was performed on the second MCP joint in 25 patients with early RA to confirm the pathologic specificity of sonographic erosions. Intraobserver reliability of sonography readings was assessed using video recordings of 55 MCP joint scans of RA patients, and interobserver reliability was assessed by comparing 160 MCP joint scans performed sequentially by 2 independent observers. RESULTS: Sonography detected 127 definite erosions in 56 of 100 RA patients, compared with radiographic detection of 32 erosions (26 [81%] of which coincided with sonographic erosions) in 17 of 100 patients (P < 0.0001). In early disease, sonography detected 6.5-fold more erosions than did radiography, in 7.5-fold the number of patients. In late disease, these differences were 3.4-fold and 2.7-fold, respectively. On MRI, all sonographic erosions not visible on radiography (n = 12) corresponded by site to MRI abnormalities. The Cohen-kappa values for intra- and interobserver reliability of sonography were 0.75 and 0.76, respectively. CONCLUSION: Sonography is a reliable technique that detects more erosions than radiography, especially in early RA. Sonographic erosions not seen on radiography corresponded to MRI bone abnormalities. This technology has potential in the management of patients with early RA/inflammatory arthritis and is likely to have major implications for the future practice of rheumatology.

Adult↗

Surgical outcome of epilepsy patients evaluated with a noninvasive protocol.

Surgery is now an accepted treatment for some medically intractable epilepsies. Presurgical evaluation is particularly important for the localization of the epileptogenic zone, which may necessitate sophisticated imaging techniques and intracranial electroencephalogram (EEG) recordings. If patients are carefully selected, however, successful results can be achieved with noninvasive evaluation methods. Seventy-seven patients were operated on for intractable seizures. All patients underwent EEG, neuropsychological, psychiatric, and magnetic resonance imaging investigations. Ictal EEG-video recording was performed in all nonlesional and in some lesional cases that had discordant data. Selective amygdalo-hippocampectomy was performed on patients with mesial temporal lobe epilepsy (MTLE), an extended or a limited lesionectomy was performed on patients with structural lesions, and a lesionectomy with deafferentation was performed on two patients with West syndrome. Electrocorticography was not used. Temporal lobe directed surgery was performed in 63.6% of the cases. The pathological examinations of all cases showed hippocampal sclerosis (HS) in 43%, tumor or tumor-like lesions in 36%, and cortical dysplasia in 5% of patients. After a mean follow-up of 17 months (range, 2-53), 75% of the patients were seizure-free with or without aura and 15% had a marked improvement, whereas 10% did not benefit from surgery. Neuropsychological outcome of patients with MTLE and HS also showed worthwhile results. Our patients, who were evaluated without pre- and perioperative intracranial recordings and other sophisticated techniques, had an outcome comparable to those in other series from more experienced centers. Our experience indicates that successful results, especially for patients with MTLE-HS and lesion-related epilepsies, can be obtained at centers with limited resources if the diagnoses and evaluation procedures are performed carefully.

Adolescent↗

Porcine transfer study: virtual reality simulator training compared with porcine training in endovascular novices.

PURPOSE: To compare the learning of endovascular interventional skills by training on pig models versus virtual reality simulators. METHODS: Twelve endovascular novices participated in a study consisting of a pig laboratory (P-Lab) and a virtual reality laboratory (VR-Lab). Subjects were stratified by experience and randomized into four training groups. Following 1 hr of didactic instruction, all attempted an iliac artery stenosis (IAS) revascularization in both laboratories. Onsite proctors evaluated performances using task-specific checklists and global rating scales, yielding a Total Score. Participants completed two training sessions of 3 hr each, using their group's assigned method (P-Lab x 2, P-Lab + VR-Lab, VR-Lab + P-Lab, or VR-Lab x 2) and were re-evaluated in both laboratories. A panel of two highly experienced interventional radiologists performed assessments from video recordings. ANCOVA analysis of Total Score against years of surgical, interventional radiology (IR) experience and cumulative number of P-Lab or VR-Lab sessions was conducted. Inter-rater reliability (IRR) was determined by comparing proctored scores with the video assessors in only the VR-Lab. RESULTS: VR-Lab sessions improved the VR-Lab Total Score (beta = 3.029, p = 0.0015) and P-Lab Total Score (beta = 1.814, p = 0.0452). P-Lab sessions increased the P-Lab Total Score (beta = 4.074, p < 0.0001) but had no effect on the VR-Lab Total Score. In the general statistical model, both P-Lab sessions (beta = 2.552, p = 0.0010) and VR-Lab sessions (beta = 2.435, p = 0.0032) significantly improved Total Score. Neither previous surgical experience nor IR experience predicted Total Score. VR-Lab scores were consistently higher than the P-Lab scores (Delta = 6.659, p < 0.0001). VR-Lab IRR was substantial (r = 0.649, p < 0.0008). CONCLUSIONS: Endovascular skills learned in the virtual environment may be transferable to the real catheterization laboratory as modeled in the P-Lab.

Adult↗

Dimensions of maternal behaviour characteristics in domestic and wildxdomestic crossbred sows.

We examined the maternal behaviour of seven domestic and seven wildxdomestic primiparous sows during 10 days post partum to investigate two questions: (1) Did maternal behaviour change during domestication? (2) Can the interindividual variability of maternal behaviour be subsumed into a few dimensions of maternal temperament? We recorded: (a) willingness to leave the nest for food on Day 2; (b) reaction to a playback of squeezed piglet distress vocalisation on Day 2; (c) spontaneous nursing behaviour and spontaneous lying-down behaviour on Day 5 (from an overnight video recording); (d) reactions to playbacks of various piglet distress vocalisations on Day 6 and (e) reactions to a human in the 'nest' with piglets on Day 9. Moreover, data on baseline cortisol saliva concentration and its increase during a brief transportation period and novel environment challenge at the age of 5 months were available. Crossbred sows did not differ from domestic ones in any aspect of maternal behaviour except for a higher tendency to terminate final massage during nursings and a higher frequency of changing posture from lying to standing and back during the night. Factor analysis (based on correlation matrix of 11 behaviour and cortisol variables calculated for all 14 sows after removing the effect of breed) indicated that 82% of the variability in the data could be explained by three factors: first, 'calmness' on which low night time frequency of major posture changes, carefulness of lying-down behaviour and high propensity to remain in nursing position after milk ejection loaded positively while cortisol concentrations during challenge loaded negatively; second, 'protectiveness' with high loadings of the reaction scores to the playbacks of piglet distress calls and the human presence near the piglets; and third, 'nursing activity' which was strongly positively associated with nursing frequency, and negatively with the proportion of nutritive nursings and baseline cortisol values. The results indicate that most aspects of pig maternal behaviour have not been significantly changed by domestication and that substantial variability in maternal behaviour exists between sows, perhaps in the form of several behaviour characteristics which encompass both behaviour and endocrine profiles of the sows.

Journal Article↗

Use of videotape to assess mobility in a controlled randomized crossover trial of physiotherapy in chronic multiple sclerosis.

OBJECTIVES: To determine to what degree assessment of mobility based on comparison of videotape recordings before and after courses of physiotherapy in patients with chronic multiple sclerosis (MS) is reliable, correlates with 'live' assessments and indicates benefit. DESIGN: Prospective data collection within a randomized crossover controlled trial of physiotherapy at home, as an outpatient, or 'no therapy' in 40 patients. SETTING: Hospital outpatients: outpatient and home physiotherapy. OUTCOMES: Mobility change based on a comparison of short video recordings before and after each treatment period was scored independently by two physiotherapists blinded to therapy type and other measures of outcome. Scores were compared with changes in the Rivermead Mobility Index (RMI) and other indices assessed by a physiotherapist in the patient's home. RESULTS: The two video observers agreed substantially on patient outcome. Changes in walking based on video correlated with RMI for home treatment (r = 0.41, p = 0.008) but not for hospital or no treatment periods (r = 0.14 and 0.15): video changes correlated with the 'live' assessor's global change score inconsistently ('no therapy' r = 0.48, p = 0.002, hospital r = 0.30, p = 0.06 and home r = 0.17, p = 0.30 treatment periods). Based on video data alone, improved mobility was evident following home therapy for only one observer but not for the other or the averaged scores of both. CONCLUSION: There was substantial agreement between two observers deciding on change in mobility based on independent blinded evaluation of short video sequences. However the correlations of these with 'live' assessments were variable. Physiotherapy had a less clear benefit on mobility based on video analysis alone compared with 'live' assessments. The study highlights the need for more objective measures of habitual mobility over longer periods.

Adult↗

Reliability and validity of the Observational Gait Scale in children with spastic diplegia.

The aim of this study was to establish the reliability and validity of visual gait assessment in children with spastic diplegia, who were community or household ambulators, using a modified version of the Physicians Rating Scale, known as the Observational Gait Scale (OGS). Two clinicians viewed edited split-screen video recordings of 20 children/adolescents (11 males, 9 females; mean age 12 years, range 6 to 21 years) made at the time of three-dimensional gait analysis (3-DGA). Walking ability in each child was scored at initial assessment and reassessed from the same videos three months later using the first seven sections of the OGS. Validity of the OGS score was determined by comparison with 3-DGA. The OGS was found to have acceptable interrater and intrarater reliability for knee and foot position in mid-stance, initial foot contact, and heel rise with weighted kappas (wk) ranging from 0.53 to 0.91 (intrarater) and 0.43 to 0.86 (interrater). Comparison with 3-DGA suggests that these sections might also have high validity(wk range 0.38-0.94). Base of support and hind foot position had lower interrater and intrarater reliabilities (wk 0.29 to 0.71 and wk 0.30 to 0.78 respectively) and were not easily validated by 3-DGA.

Adolescent↗

Electroencephalographic (EEG) video monitoring.

Electroencephalographic (EEG) video monitoring is the simultaneous documentation of the clinical and electroencephalographic manifestations of seizures. The video recording permits repeated viewing of the clinical sequence and enables comparisons with recordings of known seizures. Epilepsy is a clinical diagnosis in which most cases can be characterized with the standard clinical history, examination, and EEG. Studies of the treatment of intractable seizures (unsatisfactory control of seizure) indicate that more complex cases may require the data obtained with EEG video monitoring. For patients with intractable seizures, EEG video monitoring may help to confirm or support a diagnosis of epilepsy or confirm or support a differential diagnosis of physiologic or psychogenic seizures (nonepileptic attacks) from epilepsy. Monitoring also may provide a more accurate classification of the epileptic seizures and, for patients evaluated for surgical treatment, establish clinical focality. Estimates of the percentage of epilepsy patients requiring EEG video monitoring range from 5 to 30 percent. The average length of monitoring is approximately 10 to 16 days. In some cases outpatient monitoring in conjunction with activation procedures provides patient evaluation in only 6 to 8 hours.

Attitude of Health Personnel↗

Sources of noise in digital subtraction radiography.

In 17 patients, three identical radiographic examinations were performed for the lower premolar-molar region, by two examiners at one visit and by one examiner again approximately 3 months later. Recordings were performed with a newly developed device. The radiographs were converted to digital images in the following way: (1) video camera recording of the radiograph obtained at first visit by the first examiner (A), (2) copying of the numeric image of this radiograph (B), (3) repeated video recording of this radiograph (C), (4) video recording of the radiograph obtained at first visit by the second examiner (D), and (5) video recording of the radiograph obtained after 3 months (E). Subtractions were performed between the images: B - A, C - A, D - A, and E - A. The standard deviation of the histogram for the distribution of gray shades in the subtraction images was used to evaluate noise in the image. The standard deviation was 1.3 between B - A, 2.8 between C - A, 4.0 between D - A, and 4.1 between E - A. Physical noise originating from the video camera and the analog-to-digital conversion process thus constituted the major part of noise seen in subtraction images performed between radiographs recorded with a time interval. This indicates that reproducible recordings could be performed with the present device, which, in combination with a subtraction program able to correct for some geometry and density differences, may aid the use of subtraction radiography in clinical trials.

Adolescent↗

Motor disturbances in mice with deficiency of the sodium channel gene Scn8a show features of human dystonia.

The med(J) mouse with twisting movements related to deficiency of the sodium channel Scn8a has been proposed as a model of kinesiogenic dystonia. This prompted us to examine the phenotype of these mice in more detail. By cortical electroencephalographic (EEG) recordings, we could not detect any changes, demonstrating that the motor disturbances are not epileptic in nature, an important similarity to human dystonia. The significantly decreased body weight of med(J) mice was related to reduced food intake. Observations in the open field and by video recordings revealed that the mice exhibit sustained abnormal postures and movements of limbs, trunk and tail not only during locomotor activity but also at rest. With the exception of the head tremor, the other motor impairments were persistent rather than paroxysmal. When several neurological reflexes were tested, alterations were restricted to the posture and righting reflexes. Results of the wire hang test confirmed the greatly reduced muscle strength in the med(J) mouse. In agreement with different types of human dystonia, biperiden, haloperidol and diazepam moderately reduced the severity of motor disturbances in med(J) mice. In view of the sodium channel deficiency in med(J) mice, the beneficial effects of the sodium channel blocker phenytoin was an unexpected finding. By immunohistochemical examinations, the density of nigral dopaminergic neurons was found to be unaltered, substantiating the absence of pathomorphological abnormalities within the brain of med(J) mice shown by previous studies. With the exception of muscle weakness, many of the features of the med(J) mouse are similar to human idiopathic dystonia.

Animals↗

[Cap image--a new kind of computer-assisted video image analysis system for dynamic capillary microscopy].

We describe a newly developed multi-function video image analysis system for the computer-aided evaluation of capillaroscopic findings in microcirculation research. The Cap image analysis system comprises an IBM-compatible PC with a Matrox image processing card and real-time video tape digitalization. The video recorder is driven by a personal computer to which it is connected via an RS-232 interface. In contrast to currently available systems, the program presented here makes it possible to select any of several integrated image analysis functions, depending on the quality of the video image. Some examples of the analysis functions available are measurements of erythrocyte flow velocity using the line shift diagram method, the spatial correlation method, and the auto flying spot method. The standard features of the new program include a number of special functions and automatic movement correction. The system thus makes it possible not only to measure numerous morphological parameters such as capillary diameter, length, torquation index and capillary density, but also to perform video densitometric analysis, for example using fluorescent dyes.

Blood Flow Velocity↗