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PubMed2006

When ambiguity hurts: social standards moderate self-appraisals in generalized social phobia.

Thirty-nine individuals with generalized social phobia (social anxiety disorder) and 39 nonclinical controls performed a public speech after receiving cues about social standards. Using a novel video manipulation paradigm, one third of participants received cues indicating that standards for performance were high, one third received cues that standards were low, and the remaining third were given no explicit information about expected standards (i.e., standards were ambiguous). Individuals with social phobia performed objectively worse than controls in all conditions, but rated their performance as being worse only in the high and ambiguous standards conditions. These results suggest that in social phobia, negative self-perception is context-dependent. Implications for the cognitive model and treatment are discussed.

Adolescent↗

PubMed1997

Videotaped interviewing of non-English speakers: training for medical students with volunteer clients.

In a multicultural society such as Australia, with over 20% of its population born overseas, interpreters are often required to facilitate medical interviews. However, where a patient has some proficiency in English, medical interviews are sometimes conducted across the boundaries of culture and language. This is a report of an educational innovation to teach interviewing skills to pre-clinical medical students with the assistance of volunteers of non-English-speaking backgrounds. Pre-clinical students interviewed community volunteers on topics of general life history in a sequence of 16 tutorials. Each student conducted two interviews. Teaching methods included feedback from the volunteers, tutorial discussion facilitated by playback of videotapes, and modelling of skills by the teachers. Evaluations by volunteers and students indicated high satisfaction with the teaching methods and outcomes. Students gained confidence in interviewing people from different cultures. Evaluation of students' pairs of videotapes by an independent rater achieved satisfactory reliabilities and indicated significant gains in inquiry skills and the communication of positive attitudes. Skills in communicating empathy and in using simple language did not improve measurably.

Adult↗

PubMed2003

Psychogenic nonepileptic seizures: acute change in event frequency after presentation of the diagnosis.

Seizure frequency during inpatient video EEG monitoring was examined before and after the diagnosis of psychogenic nonepileptic seizures (PNES) was presented to patients (N=22). A control group of 10 patients with epileptic seizures (ES) were also followed from pre- to postdiagnosis. The number of PNES or ES within the 24-hour period prior to diagnosis was compared with the number of events that occurred within the 24-hour period after presentation of the diagnosis. Findings indicate that patients with PNES had a significant decrease in the frequency of events after diagnosis, while those with ES showed no change in event frequency after diagnosis. Eighteen of twenty-two patients with PNES had no further events during an acute follow-up period. Results suggest that providing patients with a diagnosis of PNES appears to reduce the acute frequency of PNES and may be an important first step in the long-term remediation of PNES. Long-term follow-up is needed to determine if such feedback alters the course of the disorder.

Acute Disease↗

PubMed2004

Factors affecting feasibility and acceptability of a practice-based educational intervention to support evidence-based prescribing: a qualitative study.

BACKGROUND: Inappropriate and costly GP prescribing is a major problem facing Primary Care Trusts. Educational outreach into practices, alongside other measures, such as audit and feedback, have the potential to enable GP prescribing to become more evidence based. High GP prescribing costs are associated with GPs who see drug company representatives; tend to end consultations with prescriptions; and 'try out' new drugs on an 'ad hoc basis' and use this as evidence of the drug's effect. An educational intervention called 'reflective practice' was developed to meet these and other educational needs. The design of the intervention was informed by studies that have identified the pre-requisites of successful behaviour change in general practice. OBJECTIVES: The study investigated the following: (i) Is it feasible for GPs to attend the sessions included in the educational intervention? (ii) Is the intervention acceptable to the participants and the session facilitators? (iii) What are the barriers to the group educational processes, and how can these be overcome? METHODS: Four practices were recruited in South West England, all of them experiencing problems with prescribing appropriateness and cost. Reflective practice sessions (including a video-taped scenario) were run in each of these practices and qualitative methods were used to explore the complex attitudes and behaviour of the participants. A researcher observed and audio-taped sessions in each practice. At the end of the programme, a sample of doctors and all the facilitators were interviewed about their experiences. The recorded data were transcribed and analysed using standard qualitative methods. RESULTS: The doctors in the largest partnerships were those who had the greatest difficulty in attending the sessions. Elsewhere, doctors were also reluctant to become involved because of previous experience of top-down managerial initiatives about prescribing quality. Facilitators came from a broad range of professional backgrounds. While knowledge of prescribed drug management issues was important, the professional background of the facilitator was less important than group facilitation skills in creating a group process which participating GPs found satisfactory. The video-taped scenario was found to be useful to set the scene for the discussion. Preserving the anonymity of responses of the GPs in the initial stages of the sessions was important in ensuring honesty in the discussion. Reaching a consensus on management of common conditions was sometimes difficult, partly because the use of the term 'best buy' implies economic pressures, rather than benefits to patients, and partly because of the value with which GPs regard the concept of clinical autonomy. 'Reflective Practice' appeared to have the potential to make GPs aware of the link to be made between their clinical management decisions and the evidence provided by the British National Formulary and Clinical Evidence. CONCLUSION: The study indicates the importance of preparing the practice adequately, including providing protected time for all GPs to attend the educational intervention. Scenarios and the structure of the sessions need to make more explicit the links between everyday practice and published evidence of effectiveness. Emphasis on cost-effectiveness may be counterproductive and wider benefits need to be emphasized. We have also identified the skill profile of the facilitator role. Our study indicates a need for a clearer understanding of GPs' perception of clinical autonomy and how this conflicts with the goal of agreement on practice guidelines for treatment. The intervention is now ripe for further development, perhaps by integrating it with other interventions to change professional behaviour. The improved intervention should then be evaluated in a randomized controlled trial.

Attitude of Health Personnel↗

PubMed2006

Behavioral and electromyographic characterization of mice lacking EphA4 receptors.

EphA4 receptors play an important role in axon guidance during development. Disrupting the expression of these receptors in mice has been shown to modify neuronal connections in the spinal cord and results in the production of a characteristic hopping gait. The EphA4-null mouse has been used in numerous investigations aimed at establishing mechanisms responsible for patterning motor activity during walking. However, there have been no detailed behavioral or electrophysiological studies on adult EphA4-null mice. We used high-speed video recordings to determine the coordination of leg movements during locomotion in adult EphA4-null mice. Our data show that the hopping movements of the hind legs are not always associated with synchronous movements of forelegs. The coupling between the forelegs is weak, resulting in changes in their phase relationship from step to step. The synchronous coordination of the hind legs can switch to an alternating pattern for a short period of time during recovery from isoflurane anesthesia. Comparison of the kinematics of hind leg movements in EphA4-null mice and wild-type animals shows that besides the synchronous coordination in EphA4-null mice, the swing durations and the swing amplitude are shorter. Electromyographic recordings from a knee extensor muscle show double bursting in the EphA4-null animals but single bursts in wild types. This double burst changes to single-burst activity during swimming and when hind legs are stepping in alternation. These observations suggest an influence of sensory feedback in shaping the pattern of muscle activity during locomotion in the mutant animals. Our data give the first detailed description of the locomotor behavior of an adult mouse with genetically manipulated spinal networks.

Animals↗

PubMed2000

A picture is worth a thousand words: practical use of videotape in teaching.

Videotapes, through vividly displayed clinical images and teaching interactions, are valuable tools for both learners and teachers. Visual images in combination with verbal instruction have been shown to significantly increase recall and retention. Many clinicians and medical teachers are aware of videotape resources, but have not had a chance to develop their use in medical education. In this paper, we discuss creative applications of videotapes in three major categories: presenting information, triggering discussion, and as a tool for direct self-observation and feedback. Videotapes may be valuable for presenting information in settings of didactic instruction; for triggering discussion during teaching workshops; and for self-observation of patient-doctor interactions and learner-teacher encounters. The article presents learner-centered approaches to review a videotaped clinical encounter in order to enhance value and comfort for the learner and teacher. Sources of tapes include on-site videotaping, published educational tapes and commercial tapes shown in accordance with fair use guidelines, examples of which are referenced. Videotapes add another dimension to traditional sources of physician education.

Clinical Competence↗

PubMed1997

Visual perception modifies goal-directed movement control: supporting evidence from a visual perturbation paradigm.

It is well known that dynamic visual information influences movement control, whereas the role played by background visual information is still largely unknown. Evidence coming mainly from eye movement and manual tracking studies indicates that background visual information modifies motion perception and might influence movement control. The goal of the present study was to test this hypothesis. Subjects had to apply pressure on a strain gauge to displace in a single action a cursor shown on a video display and to immobilize it on a target shown on the same display. In some instances, the visual background against which the cursor moved was unexpectedly perturbed in a direction opposite to (Experiment 1), or in the same direction as (Experiment 2) the cursor controlled by the subject. The results of both experiments indicated that the introduction of a visual perturbation significantly affected aiming accuracy. These results suggest that background visual information is used to evaluate the velocity of the aiming cursor, and that this perceived velocity is fed back to the control system, which uses it for on-line corrections.

Adult↗

PubMed1997

Endoscopically guided percutaneous repair of inguinal hernia through a 2-cm incision. Minihernia repair.

BACKGROUND: The laparoscopic repair of inguinal hernia is still controversial. Transabdominal preperitoneal repair violates the peritoneal cavity and may result in visceral injuries or intestinal obstruction. The laparoscopic extraperitoneal approach has the disadvantage of being technically demanding and requires extensive extraperitoneal mobilization. The Lichtenstein repair gives good long-term results, is easy to learn, can be performed under local anesthesia, but requires a larger incision. METHODS: We describe a novel percutaneous tension-free prosthetic mesh repair performed through a 2-cm groin incision. The inguinal canal is traversed with the aid of a 5-mm video-endoscope and the canal is widened using specially designed balloons. Spermatic cord mobilization, identification and excision of the indirect sac, and posterior wall repair are carried out under endoscopic guidance. RESULTS: Between October 1993 and July 1995, 85 primary inguinal hernia repairs (48 indirect and 33 direct) were performed on 81 patients (80 men, one woman) by the author (A.D.). The mean age was 41 years (range 17-83 years). Six repairs were performed under local anesthetic. Mean operative time was 42 min (range 25-74). Mean hospital stay was 1.2 days (0-3 days). The mean return to normal activity was 8 days (2-10 days). Eight complications have occurred: a serous wound discharge, two scrotal hematomas, a scrotal swelling that resolved spontaneously, wound pain lasting 2 weeks, an episode of urinary retention, and two recurrences early in the series (follow-up 1-22 months). CONCLUSION: The endoscopically guided percutaneous hernia repair avoids the disadvantages of laparoscopy (i.e., lack of stereoscopic vision, reduced tactile feedback, unfamiliar anatomical approach, risk of visceral injury), yet the use of endoscopic instrumentation allows operation through a 2-cm incision. The minihernia repair thus combines the virtues of an open tension-free repair with minimal access trauma.

Adolescent↗

PubMed1997

Sensory modulation and behavioral choice during feeding in the Australian frog, Cyclorana novaehollandiae.

This study investigates how visual and tactile sensory information, as well as biomechanical effects due to differences in physical characteristics of the prey, influence feeding behavior in the frog Cyclorana novaehollandiae. Video motion analysis was used to quantify movement patterns produced when feeding on five prey types (termites, waxworms, crickets, mice and earthworms). Twelve kinematic variables differed significantly among prey types, and twelve variables were correlated with prey characteristics (including mass, length, height and velocity of movement). Results indicate that C. novaehollandiae uses a different strategy to capture each prey type. Visual assessment of prey characteristics appeared to be more important in modulating feeding behavior that tactile cues or biomechanical effects. We propose a hierarchical hypothesis of behavioral choice, in which decisions are based primarily on visual analysis of prey characteristics. In this model, the frogs first choose between jaw prehension and tongue prehension based on prey size. If they have chosen jaw prehension, they next choose between upward or downward head rotation based on length and height of the prey. If they have chosen tongue prehension, they next choose between behavior for fast and slow prey. Final decisions may be the result of behavioral fine tuning based on tactile feedback.

Aging↗

PubMed2006

On algorithmic rate-coded AER generation.

This paper addresses the problem of converting a conventional video stream based on sequences of frames into the spike event-based representation known as the address-event-representation (AER). In this paper we concentrate on rate-coded AER. The problem is addressed as an algorithmic problem, in which different methods are proposed, implemented and tested through software algorithms. The proposed algorithms are comparatively evaluated according to different criteria. Emphasis is put on the potential of such algorithms for a) doing the frame-based to event-based representation in real time, and b) that the resulting event streams ressemble as much as possible those generated naturally by rate-coded address-event VLSI chips, such as silicon AER retinae. It is found that simple and straightforward algorithms tend to have high potential for real time but produce event distributions that differ considerably from those obtained in AER VLSI chips. On the other hand, sophisticated algorithms that yield better event distributions are not efficient for real time operations. The methods based on linear-feedback-shift-register (LFSR) pseudorandom number generation is a good compromise, which is feasible for real time and yield reasonably well distributed events in time. Our software experiments, on a 1.6-GHz Pentium IV, show that at 50% AER bus load the proposed algorithms require between 0.011 and 1.14 ms per 8 bit-pixel per frame. One of the proposed LFSR methods is implemented in real time hardware using a prototyping board that includes a VirtexE 300 FPGA. The demonstration hardware is capable of transforming frames of 64 x 64 pixels of 8-bit depth at a frame rate of 25 frames per second, producing spike events at a peak rate of 10(7) events per second.

Algorithms↗

PubMed2004

Stratum oriens horizontal interneurone diversity and hippocampal network dynamics.

In this last decade, the combination of differential interference contrast infrared video technology and patch-clamp techniques applied to slices in vitro has allowed the routine electrophysiological recording of visually identified central neurones. This has opened the way to the possibility of preselecting GABAergic interneurones of the hippocampus on the basis of some peculiar morphological characteristics. In particular, stratum oriens 'horizontal' interneurones are easily recognizable in living hippocampal slices because of their location and bipolar/bitufted appearance. Thus, this class of cells has rapidly risen as one of the most studied in the entire hippocampus. In this review, I will try to assemble the vast electrophysiological knowledge on these interneurones into a more focused picture, which is relevant for network activity in vitro and in vivo.

Animals↗

PubMed2004

Modulation of mechanosensory responses by motoneurons that regulate skin surface topology in the leech.

Central regulation of somatosensory signals has been extensively studied, but little is known about their regulation in the periphery. Given the widespread exposure of the skin sensory terminals to the environment, it is of interest to explore how somatosensory sensitivity is affected by changes in properties of the skin. In the leech, the annuli that subdivide the skin can be erected under the control of the annulus erector (AE) motoneurons. To analyze whether this surface change influences mechanosensory sensitivity, we studied the responses of low threshold mechanosensory T cells to mechanical stimulation of the skin as AE motoneurons were activated. In segments of the body wall connected to the corresponding ganglion and submerged in an aqueous environment, T cells responded to localized bubbling on the skin and to water flow parallel to its surface. Excitation of AE motoneurons diminished these responses in a way that depended on the motoneuron firing frequency. Video recordings established that the range of AE firing frequencies that produced effective annulus erection coincided with that influencing T cell responses. In isolated ganglia, AE firing had no effect on T cell excitability, suggesting that annulus erection diminished T cell responsiveness to mechanical input. Counteracting this effect, mechanosensory inputs inhibited AE motoneurons. However, because depolarization of AE cells caused a decrease in their input resistance, the more active the motoneuron, the less sensitive it became to inhibitory signals. Thus when brought to fire, AE motoneurons would stay "committed" to a high activity level, and this would limit sensory responsiveness to incoming mechanical signals.

Animals↗

PubMed2006

Neurophysiology of prehension. II. Response diversity in primary somatosensory (S-I) and motor (M-I) cortices.

Prehension responses of 76 neurons in primary somatosensory (S-I) and motor (M-I) cortices were analyzed in three macaques during performance of a grasp and lift task. Digital video recordings of hand kinematics synchronized to neuronal spike trains were compared with responses in posterior parietal areas 5 and AIP/7b (PPC) of the same monkeys during seven task stages: 1) approach, 2) contact, 3) grasp, 4) lift, 5) hold, 6) lower, and 7) relax. S-I and M-I firing patterns signaled particular hand actions, rather than overall task goals. S-I responses were more diverse than those in PPC, occurred later in time, and focused primarily on grasping. Sixty-three percent of S-I neurons fired at peak rates during contact and/or grasping. Lift, hold, and lowering excited fewer S-I cells. Only 8% of S-I cells fired at peak rates before contact, compared with 27% in PPC. M-I responses were also diverse, forming functional groups for hand preshaping, object acquisition, and grip force application. M-I activity began < or =500 ms before contact, coinciding with the earliest activity in PPC. Activation of specific muscle groups in the hand was paralleled by matching patterns of somatosensory feedback from S-I needed for efficient performance. These findings support hypotheses that predictive and planning components of prehension are represented in PPC and premotor cortex, whereas performance and feedback circuits dominate activity in M-I and S-I. Somatosensory feedback from the hand to S-I enables real-time adjustments of grasping by connections to M-I and updates future prehension plans through projections to PPC.

Animals↗

PubMed1989

The use of videonasopharyngoscopy for biofeedback therapy in adults after pharyngeal flap surgery.

Nasopharyngoscopy with videorecording was used as a visual feedback therapy tool to establish and promote consistent closure of the velopharyngeal ports during connected speech after pharyngeal flap surgery. Of the three adults in this report, two achieved consistent closure during connected discourse and have been discharged from therapy; the third demonstrated improved velopharyngeal closure but elected not to continue therapy. These outcomes demonstrate that nasopharyngoscopy biofeedback therapy is useful in helping the motivated adult to achieve better velopharyngeal closure during connected speech after pharyngeal flap surgery or revision. This type of therapy may also prove beneficial with children.

Adult↗

PubMed1992

Cell-to-cell spread of calcium signals mediated by ATP receptors in mast cells.

Rat basophilic leukaemia cells, like mast cells from which they are derived, have surface Fc epsilon receptors that trigger secretion of inflammatory mediators when crosslinked. Both GTP-binding proteins and a rise in cytosolic calcium concentration ([Ca2+]i) are implicated in the secretory mechanism. Here we use a video-imaging technique to report that transient rises in [Ca2+]i initiated in an individual cell can spread from cell to cell in a wave-like pattern by means of a secreted intermediate, in the absence of gap-junctional communication. We find that the leukaemia cells, peritoneal mast cells and mucosal mast cells have cell-surface P2-type purinergic receptors that can trigger similar [Ca2+]i transients. We provide evidence that ATP is rapidly released, and that it can amplify [Ca2+]i signals and initial secretory responses during antigen-stimulation of rat basophilic leukaemia cells.

Animals↗

PubMed2003

Causes and prevention of laparoscopic bile duct injuries: analysis of 252 cases from a human factors and cognitive psychology perspective.

OBJECTIVE: To apply human performance concepts in an attempt to understand the causes of and prevent laparoscopic bile duct injury. SUMMARY BACKGROUND DATA: Powerful conceptual advances have been made in understanding the nature and limits of human performance. Applying these findings in high-risk activities, such as commercial aviation, has allowed the work environment to be restructured to substantially reduce human error. METHODS: The authors analyzed 252 laparoscopic bile duct injuries according to the principles of the cognitive science of visual perception, judgment, and human error. The injury distribution was class I, 7%; class II, 22%; class III, 61%; and class IV, 10%. The data included operative radiographs, clinical records, and 22 videotapes of original operations. RESULTS: The primary cause of error in 97% of cases was a visual perceptual illusion. Faults in technical skill were present in only 3% of injuries. Knowledge and judgment errors were contributory but not primary. Sixty-four injuries (25%) were recognized at the index operation; the surgeon identified the problem early enough to limit the injury in only 15 (6%). In class III injuries the common duct, erroneously believed to be the cystic duct, was deliberately cut. This stemmed from an illusion of object form due to a specific uncommon configuration of the structures and the heuristic nature (unconscious assumptions) of human visual perception. The videotapes showed the persuasiveness of the illusion, and many operative reports described the operation as routine. Class II injuries resulted from a dissection too close to the common hepatic duct. Fundamentally an illusion, it was contributed to in some instances by working too deep in the triangle of Calot. CONCLUSIONS: These data show that errors leading to laparoscopic bile duct injuries stem principally from misperception, not errors of skill, knowledge, or judgment. The misperception was so compelling that in most cases the surgeon did not recognize a problem. Even when irregularities were identified, corrective feedback did not occur, which is characteristic of human thinking under firmly held assumptions. These findings illustrate the complexity of human error in surgery while simultaneously providing insights. They demonstrate that automatically attributing technical complications to behavioral factors that rely on the assumption of control is likely to be wrong. Finally, this study shows that there are only a few points within laparoscopic cholecystectomy where the complication-causing errors occur, which suggests that focused training to heighten vigilance might be able to decrease the incidence of bile duct injury.

Adult↗

PubMed2003

Electromyographic activity of the lip muscle as a measure of puffing on a cigarette.

The electromyographic activity (EMG) of the upper lip muscle (m. orbicularis oris) during sucking on a cigarette was examined as a potential new measure of smoking behaviour. This parameter was examined under conditions of actual smoking, sham smoking and sucking on a straw. We applied psychophysical procedures (methods of magnitude production), normal and paced smoking, two conventional means to confirm puffing (video recording and changes in air pressure in a cigarette holder) on different groups of smokers (heavy and light). The data revealed that lip-EMG is a valid and reliable means to quantify sucking on a cigarette in a variety of situations common to the study of smoking. It was concluded that lip-EMG may be a sensitive and selective measure of motor activity associated with smoking. The lip-EMG may also be applied together with hand activity and breathing to identify individual puffing, particularly in heavy smokers and during actual smoking. Discussed were several applications of this method to the study of smoking and other motivated behaviour such as consumption of water and palatable fluids.

Adult↗

PubMed1997

An instrumented glove for grasp specification in virtual-reality-based point-and-direct telerobotics.

Hand posture and force, which define aspects of the way an object is grasped, are features of robotic manipulation. A means for specifying these grasping "flavors" has been developed that uses an instrumented glove equipped with joint and force sensors. The new grasp specification system will be used at the Pennsylvania State University (Penn State) in a Virtual Reality based Point-and-Direct (VR-PAD) robotics implementation. Here, an operator gives directives to a robot in the same natural way that human may direct another. Phrases such as "put that there" cause the robot to define a grasping strategy and motion strategy to complete the task on its own. In the VR-PAD concept, pointing is done using virtual tools such that an operator can appear to graphically grasp real items in live video. Rather than requiring full duplication of forces and kinesthetic movement throughout a task as is required in manual telemanipulation, hand posture and force are now specified only once. The grasp parameters then become object flavors. The robot maintains the specified force and hand posture flavors for an object throughout the task in handling the real workpiece or item of interest. In the Computer integrated Manufacturing (CIM) Laboratory at Penn State, hand posture and force data were collected for manipulating bricks and other items that require varying amounts of force at multiple pressure points. The feasibility of measuring desired grasp characteristics was demonstrated for a modified Cyberglove impregnated with Force-Sensitive Resistor (FSR) (pressure sensors in the fingertips. A joint/force model relating the parameters of finger articulation and pressure to various lifting tasks was validated for the instrumented "wired" glove. Operators using such a modified glove may ultimately be able to configure robot grasping tasks in environments involving hazardous waste remediation, flexible manufacturing, space operations and other flexible robotics applications. In each case, the VR-PAD approach will finesse the computational and delay problems of real-time multiple-degree-of-freedom force feedback telemanipulation.

Biomechanical Phenomena↗