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At least 235 records · Page 13Linked to original sources
PubMed1997

Neural correlates of a spatial sensory-to-motor transformation in primary motor cortex.

Primary motor cortex (MC) has been strongly implicated in motor processing, but there have been relatively few attempts to determine whether MC may also play a role in either sensory or context-dependent processing. In the present study, neuronal activity in MC was characterized in relation to the planning and execution of visually instructed limb movements whose trajectories were dissociated from their spatial targets. This design permitted the dissociation of neuronal activity related to motor processing from activity related to sensory or context-dependent processing. Two macaque monkeys were trained to perform a visually instructed, delayed reaching paradigm with indirect visual feedback. Subjects used the right forelimb to capture targets presented on a video display by moving a two-dimensional joystick whose position was reflected by a cursor. The target to be capture on each trial was indicated by a visual instruction stimulus (IS), which was separated from a movement-triggering stimulus (TS) by a variable delay. The direction of forelimb movement was dissociated from the location of the target by varying the spatial mappings between joystick and cursor across two conditions, unrotated (0 degrees offset between cursor and limb direction) and rotated (90 degrees offset). Task-related activity was recorded from a total of 180 MC neurons. The focus of this study was on directionally tuned neuronal activity that included phasic, stimulus-related activity following the IS; tonic, set-related activity between IS and TS; and phasic, movement-related activity following the TS. Of the entire sample of MC neurons with directionally tuned activity, 119 cells were tested both under rotation conditions, permitting dissociation of directional responses that depended on target locations from those that depended on limb trajectory. Task-related neuronal activity was classified as target dependent if it covaried exclusively with target location across both conditions, and as limb dependent if it covaried exclusively with limb trajectory. Directional activity that did not fulfill criteria for either target or limb dependence, because of changes across rotation conditions, was classified as complex. Approximately one quarter of MC neurons showed weak, but consistent, stimulus-related activity that was directionally tuned (24%, 29 of 119). Nearly all of the directionally classifiable stimulus-related activity was target dependent (94%, 15 of 16 responses), with the exception of a single limb-dependent response (6%, 1 of 16). A majority of MC neurons showed set-related activity that was directionally tuned (61%, 72 of 119). Of the directionally classifiable set-related activity, there were comparable numbers of target-dependent (37%, 16 of 43) and limb-dependent responses (35%, 15 of 43), with the remainder being complex (27%, 12 of 43). Movement-related activity following the TS was considered to be early or late, depending on whether it preceded or followed the onset of movement. The large majority of MC neurons showed early movement-related activity that was directionally tuned (86%, 102 of 119): among those whose neurons early activity was directionally classifiable, there were only one third as many target-dependent responses (14%, 11 of 79) as limb-dependent responses (43%, 34 of 79), with the remainder being complex (43%, 34 of 79). There was also a large majority of MC neurons that showed late movement-related activity that was directionally tuned (84%, 100 of 119): among those whose late activity was directionally classifiable, there were only one ninth as many target-dependent responses (5%, 4 of 88) as there were limb-dependent responses (41%, 36 of 88), with the remainder being complex (55%, 48 of 88). The instructed delay task employed in this study required a sensory-to-motor transformation through which the instructed target location was associated with a limb movement of the appropriate direction. (ABSTRACT TRUNCATED)

Action Potentials↗
PubMed2005

Video gaming promotes concussion knowledge acquisition in youth hockey players.

While the positive uses for video games in an educational setting have also been established, the educational aim is usually made explicit. The goal of this research was to develop a video game wherein the educational aspect was implicitly embedded in the video game, such that the gaming activity remained interesting and relevant. Following a pilot study to confirm the usability of an in-house developed game, two studies were conducted with 11-17 year old hockey players (N(1)=130, N(2)=39). Results demonstrated that participants playing the experimental version of the video game scored significantly higher on a concussion symptoms questionnaire, in a significantly faster time, than participants playing the control version of the game. Most participants indicated that they enjoyed the game and would play it again. These results suggest that educational material can be conveyed successfully and in an appealing manner via video game play.

Adolescent↗
PubMed2006

Loading the limb during rhythmic leg movements lengthens the duration of both flexion and extension in human infants.

Sensory input is critical for adapting motor outputs to meet environmental conditions. A ubiquitous force on all terrestrial animals is gravity. It is possible that when performing rhythmic movements, animals respond to load-related feedback in the same way by prolonging the muscle activity resisting the load. We hypothesized that for rhythmic leg movements, the period (extension or flexion) experiencing the higher load will be longer and vary more strongly with cycle period. Six rhythmic movements were studied in human infants (aged 3-10 mo), each providing different degrees of load-related feedback to the legs during flexion and extension of the limb. Kicking in supine provided similar loads (inertial) during flexion and extension. Stepping on a treadmill, kicking in supine against a foot-plate, and kicking in sitting loaded the legs during extension more than flexion, whereas air-stepping and air-stepping with ankle weights did the opposite. Video, electrogoniometry, surface electromyography, and contact forces were recorded. We showed that load-related feedback could make either the duration of flexion or extension longer. Within the tasks of stepping and kicking against a plate, infants who exerted lower forces showed shorter extensor durations than those who exerted higher forces. Because older babies tend to step with greater force, we wished to rule out the contribution of age. Eight babies (>8 mo old) were studied during stepping, in which we manipulated the amount of weight-bearing. The same effect of load was seen. Hence, the degree of loading directly affects the duration of extension in an incremental way.

Aging↗
PubMed2005

Rapamycin induces tumor-specific thrombosis via tissue factor in the presence of VEGF.

Therapeutic strategies that target and disrupt the already-formed vessel networks of growing tumors are actively pursued. The goal of these approaches is to induce a rapid shutdown of the vascular function of the tumor so that blood flow is arrested and tumor cell death occurs. Here we show that the mammalian target of rapamycin (mTOR) inhibitor rapamycin, when administered to tumor-bearing mice, selectively induced extensive local microthrombosis of the tumor microvasculature. Importantly, rapamycin administration had no detectable effect on the peritumoral or normal tissue. Intravital microscopy analysis of tumors implanted into skinfold chambers revealed that rapamycin led to a specific shutdown of initially patent tumor vessels. In human umbilical vein endothelial cells vascular endothelial growth factor (VEGF)-induced tissue factor expression was strongly enhanced by rapamycin. We further show by Western blot analysis that rapamycin interferes with a negative feedback mechanism controlling this pathologic VEGF-mediated tissue factor expression. This thrombogenic alteration of the endothelial cells was confirmed in a one-step coagulation assay. The circumstance that VEGF is up-regulated in most tumors may explain the remarkable selectivity of tumor vessel thrombosis under rapamycin therapy. Taken together, these data suggest that rapamycin, besides its known antiangiogenic properties, has a strong tumor-specific, antivascular effect in tumors.

Angiogenesis Inhibitors↗
PubMed2006

A comprehensive e-education engine for a virtual diabetes centre.

It seems likely that the development of effective diabetes education for patients, carers and staff would prove highly cost-effective. Diabetes-e is an electronic diabetes encyclopaedia designed to provide comprehensive education to patients, carers (e.g. family, schools, care homes) and health professionals (specialist and non-specialist). In addition, educational media such as information leaflets (that can be printed during a consultation), streaming educational video and slide resource packs are available. Self-assessment questionnaires with feedback guide further education and facilitate targeted continuing professional development (CPD) for health professionals. The prototype has been developed with a particular emphasis on patient input. It is anticipated that Diabetes-e will be implemented across Central Nottinghamshire, including training of key personnel, by the end of 2005. The project has already gone live for insulin commencement.

Caregivers↗
PubMed1997

Influence of lift moment in determining MAWL.

An experiment was performed to determine whether maximum acceptable weight of lift (MAWL) estimates were consistent with previously reported values when the MAWL was determined without visual feedback during the weight adjustment period. Twelve healthy male students performed four lifting tasks similar to those often performed in previous psychophysical studies: floor to knuckle at 1 lift per min, floor to knuckle at 4.3 lifts per min, knuckle to shoulder at 1 lift per min, and knuckle to shoulder at 4.3 lifts per min. When compared with the previous studies with similar box dimensions, similar trends between the conditions were present, but a slight reduction in weight was usually chosen by the participant in this study. However, the results of this study agreed with previous psychophysical studies when the distance of the load from the spine (moment arm) was taken into consideration by either comparing the MAWLs with those of a large box or by comparing load moments. Hence this study shows that eliminating visual feedback during the adjustment periods did not significantly alter the MAWLs from previous studies. It also indicates that one must use caution when applying the MAWL in the workplace because the MAWL is very sensitive to moment arm.

Analysis of Variance↗
PubMed1993

Velopharyngeal sphincter physiology in deaf individuals.

Fifty-three deaf subjects with a history of prelingual profound bilateral sensorineural hearing loss, similar language habilitation with hearing aids, and normal velopharyngeal structures underwent a study protocol including speech evaluation, behavioral pure-tone audiometry, videonasopharyngoscopy, multiview videofluoroscopy, and electromyography of the velopharyngeal muscles. Subjects were divided into two groups: the first group included 13 subjects with normal nasal resonance or mild hypernasality (four normals and nine with mild hypernasality); the second group had subjects with severe hypernasality and severe articulation deficits. Pure-tone thresholds, velopharyngeal closure patterns, and electromyographic activity of velopharyngeal muscles were similar for both groups of subjects. However, in subjects with severe hypernasality, despite normal muscle activity as observed by electromyography, velopharyngeal valving activity lacked rhythm and strength during speech. It is concluded that deaf subjects may present a functional disorder of the velopharyngeal sphincter related to absence of auditory regulation during phonation. Visual biofeedback using videonasopharyngoscopy may be useful for treating this disorder.

Adolescent↗
PubMed2002

Working with interpreters: an interactive Web-based learning module.

OBJECTIVE: Medical students are presented with unique challenges when they care for patients with limited English proficiency. Students must learn a complex set of skills needed to care for patients across cultural and language barriers and to understand the impact of their own attitudes and beliefs about caring for these patients. We developed and piloted a multimedia interactive Web-based module aimed at teaching students effective strategies for working with interpreters and diverse patient populations, and at raising their awareness of important legal, ethical, and cultural issues. DESCRIPTION: First the learner completes a 37-multiple-choice-question (MCQ) pre-test that assesses attitudes, factual knowledge, and ability to analyze written clinical scenarios relevant to the module's content. Learners are then shown a series of professionally produced video vignettes, which reflect diverse patient populations, interpreters, and effectiveness of interpretation strategies (e.g., a Russian-speaking woman with chest pain whose daughter interprets, a medical student interpreting for a Chinese-speaking man using herbal medication, a Haitian woman told of an abnormal mammogram through a trained simultaneous interpreter). In each case, learners submit short answers to on-screen questions analyzing the effectiveness of the interpretation strategies demonstrated. Immediate feedback is given comparing student responses with those of experts. At any time during the module, the learners may view video commentary by legal, ethics, and cultural experts, or access a glossary and Web site links. Students conclude the module by again taking the MCQ test. A final screen compares their pre- and post-MCQ test responses and shows best answers, allowing them to assess their learning. The learners also complete a survey, providing personal cultural information and feedback on the module. DISCUSSION: All 160 first-year medical students completed the module and evaluated its effectiveness this year. On average, students improved by 20% on the MCQ post-test and 86% of the students were satisfied with the learning experience and acquired new knowledge. As a result of their participation in the module, students examined their own cultural and linguistic backgrounds and made the following comments: "I am interested in exploring the way my own culture and cultural biases could impact my working with patients from other cultures"; "This module has opened my eyes to the fears and concerns of immigrants who do not speak English." Therefore, this pilot of the module effectively imparted guidelines for, and raised awareness of, medical interpreting. The most common critique of the module was that as a result of technical difficulties, it was time-consuming. A more rigorous evaluation is planned for the next academic year. We are also working to enrich and enhance the module for more experienced clinicians (GME and CME). As a complementary educational tool, the Internet has the advantages of allowing students to work at their own paces, view engaging video clips, and participate in interactive learning with immediate feedback and self-assessment.

Communication Barriers↗
PubMed1992

Pattern generator system as a versatile visual stimulator.

We have designed and implemented a Motorola 68000 microprocessor-based pattern generator system (PGS) that uses a color video display terminal (VDT) to provide light stimuli to the intact vertebrate retina. This communication is intended for those who are considering acquisition of a commercial retinal stimulator or those who are custom designing their own pattern generator system. The discussion surveys the features to be included as well as design factors which must be considered in such a device. The memory organization of the PGS allows as stimuli multiple, complex patterns consisting of one or more disks, annuli, bars or gratings to flash or modulate in intensity according to a pre-defined function. In addition, patterns can move smoothly in any direction at selectable, uniform speeds without the re-drawing of video memory. The presence of a 12-bit A/D converter internal to the PGS allows a dynamic change in stimulus position, speed or pattern based upon physiological feedback. A physically realistic image size (0.9 cm2) and resolution (20 mu/pixel) in the retinal plane are achieved with simple intervening optics. The video field rate of 60 Hz is above the flicker fusion frequency for most vertebrate animals and does not induce artifacts in cellular responses. The PGS operating in a PC-based environment meets the requirements of a versatile optical stimulator for investigations in retinal electrophysiology.

Ambystoma↗
PubMed2004

Effects of postidentification feedback on eyewitness identification and nonidentification confidence.

Two experiments investigated new dimensions of the effect of confirming feedback on eyewitness identification confidence using target-absent and target-present lineups and (previously unused) unbiased witness instructions (i.e., "offender not present" option highlighted). In Experiment 1, participants viewed a crime video and were later asked to try to identify the thief from an 8-person target-absent photo array. Feedback inflated witness confidence for both mistaken identifications and correct lineup rejections. With target-present lineups in Experiment 2, feedback inflated confidence for correct and mistaken identifications and lineup rejections. Although feedback had no influence on the confidence-accuracy correlation, it produced clear overconfidence. Confidence inflation varied with the confidence measure reference point (i.e., retrospective vs. current confidence) and identification response latency.

Adolescent↗
PubMed2006

Development of the transtibial prosthesis controlled pneumatically and electrically by microcomputer system.

This report represents the development of the prototype transtibial prosthesis to assist a smooth and comfortable walking for an unilateral amputee. This prosthesis is composed of two air cylinders, solenoid valves, portable and small air tank for compressed air storage, a multiple sensor system and a microprocessor. Two air cylinders are located around the rods to act as antagonistic and agonistic muscles. The system causes flexion and extension of the foot plate jointed at the ankle with compressed air, injected -or discharged via a solenoid or electromagnetic valves. The valves or solenoids are controlled with a microprocessor (Microchip Technology Inc., PIC16F876), the microprocessor generates control signals to the interface circuits for valve opening and closing consistent with the foot position during the walking phase. The control patterns generated in the microprocessor are modified with feedback from the touch sensor, ankle joint angle sensor and the two dimensional acceleration sensor. The primary walking pattern for an individual amputee should be developed through the gait analysis with video.

Amputation, Surgical↗
PubMed1989

Mirror feedback and judgments of body size.

Body size perception was measured in 44 obese and normal weight subjects using a video TV methodology. Subjects performed a task whereby they manipulated the size of their body image on a TV screen. Subjects viewed their images in the presence and absence of a full length mirror. Subjects were more accurate judging body size with the mirror present. Subjects also responded more slowly and made more adjustments of their body image when the mirror was present. No differences between obese and normal weight subjects were found. Ramifications of the findings for individuals who diet are discussed.

Body Constitution↗
PubMed1992

Self-regulation of slow cortical potentials in psychiatric patients: depression.

Findings on depressive patients indicate that depressives have electrophysiological characteristics similar to those of schizophrenics, in that they exhibit reduced Contingent Negative Variation (CNV) amplitudes and more distinct Postimperative Negative Variations (PINVs) than normal controls. In a biofeedback experiment, 8 medicated male inpatients with the DSM III-R diagnosis of "Bipolar Disorder, Depressive," and "Major Depression" demonstrated no impairment in the self-regulation of Slow Cortical Potentials (SCP) in comparison to schizophrenics in terms of increasing and suppressing negativity. Continuous visual SCP feedback is presented to the patient as a horizontally moving rocket in a video game format. The direction changes of the rocket represented SCP changes at each point in time, recorded by the central EEG (based on the pretrial baseline). Depressives demonstrated SCP self-regulation across 20 sessions, although with many between-and-within variations. The 8 male controls were unable to regulate their SCPs across 5 sessions. This result contradicts other findings of our laboratory on normal controls. Motivational factors and insufficient operant reinforcement (financial reward) may have facilitated this effect.

Adult↗
PubMed2004

Predicting baseline laparoscopic surgery skills.

BACKGROUND: Laparoscopic surgery requires specialized dexterity even beyond that required for open surgery. Decreased tactile feedback, different eye-hand coordination, and translation of a two-dimensional video image into a three-dimensional working area are just some of the obstacles in the performance of laparoscopic surgery. Possession of certain nonsurgical skills may help in overcoming some of these obstacles. Prediction of baseline laparoscopic surgery skills may help further to refine the education of basic laparoscopic surgery skills. This investigation explores whether nonsurgical skills and demographic data can predict baseline laparoscopic surgery tasks. METHODS: First- and second-year students were given a survey regarding nonsurgical dexterity skills. The survey inquired about typing skills, play with computer games, ability to sew, skill with music instruments, use of chopsticks, and experience operating tools. Demographic data were requested as well. All the students underwent four tasks: placing a piece of bowel in a retrieval bag, placing a stapler on the bowel, measuring a piece of bowel, and performing a liver biopsy in a porcine animal model. Both objective (time and error) and subjective evaluation were assessed for all the tasks. Statistical analysis using analysis of variances (ANOVA) Kruskal-Wallis test with post hoc tests, two-tailed unpaired t-tests/Mann-Whitney test, and Fischer's exact tests/chi-square tests was performed when appropriate. RESULTS: There were 68 students in this investigation. Gender, medical student year, ethnicity, desire to enter a surgical field, and age were not associated with increased performance in any of the tasks. Chopstick use was associated with statistically significantly better mean time in placing a piece of bowel in a retrieval bag and measuring a piece of bowel (p < 0.04). The other nonsurgical dexterity skills did not statistically increase performance, as indicated by time, errors, or subjective scores, for the four tasks. CONCLUSIONS: It is difficult to predict baseline laparoscopic surgery skills.

Adult↗
PubMed1985

Digital coronary roadmapping as an aid for performing coronary angioplasty.

In an attempt to improve visualization of the position of the guidewire and dilatation balloon during coronary angioplasty, a method was developed called digital coronary roadmapping. With this method a digitally acquired coronary angiogram is interlaced with the live fluoroscopic image of the guidewire and balloon catheter. The digital coronary angiogram is superimposed at the same magnification and radiologic projection as the live fluoroscopic image onto the video monitor above the catheterization table. The digital roadmap image thus provides immediate feedback to the angiographer to assist in directing the guidewire into the appropriate coronary artery branch and to help in placement of the balloon so that it straddles the site of stenosis.

Adult↗
PubMed1988

Human arterial surface fluorescence: atherosclerotic plaque identification and effects of laser atheroma ablation.

In vivo plaque recognition may be important for safe and precise intra-arterial atheroma ablation during laser coronary angioplasty. This study examined the feasibility and sensitivity of utilizing quantitative fluorescence spectroscopy and video-enhanced fluorescence imaging for plaque identification in atherosclerotic human necropsy arterial wall before and after laser atheroma ablation. With wide-band (450 to 490 nm) blue light excitation, the 540 nm fluorescence intensity ratio of normal to diseased sites (n = 13) was 2.09 +/- 0.82 (p less than 0.001) and video fluorescence imaging provided enhanced delineation of atheroma surface characteristics. Continuous argon and pulsed excimer (308 nm) laser ablation of atheroma decreased fluorescence intensity ratios by 42 and 20% (p less than 0.001), respectively (that is, from abnormal to nearly normal). Low power 325 nm laser-excited fluorescence spectroscopy from normal (n = 115) and abnormal (n = 146) necropsy sites revealed an average 45% decrease in atheroma fluorescence intensity (p less than 0.0001) and changes in fluorescence spectra appearance that corresponded to plaque morphologic subtypes. Studies using a dual laser system combining 325 nm laser-excited fluorescence plaque recognition and a 480 nm pulsed dye laser for tissue ablation with common optical fibers demonstrated normalization of both fluorescence intensity and spectra appearance after laser atheroma ablation. Thus, in vitro analysis of surface arterial fluorescence by quantitative spectroscopy and video fluorescence imaging reliably differentiate plaque from normal tissue and may provide the feedback signal needed to activate a laser source for selective plaque removal.

Adult↗
PubMed2005

Doctor-patient communication and satisfaction with care in oncology.

PURPOSE OF REVIEW: This review summarises current knowledge on the impact on patient satisfaction of initiatives undertaken to enhance the communication between doctors and their patients in oncology. RECENT FINDINGS: Recent studies have assessed the effectiveness of different approaches aimed at improving doctor-patient communication in oncology. These have been assessed on outcomes related to the patient (e.g., anxiety, quality of life, medical knowledge, satisfaction) or to the doctor (e.g., communication behaviour, attitudes). Patient satisfaction has been recognised as a particularly relevant outcome, and a positive effect of recent initiatives to improve the interaction between cancer patients and their doctors on patient satisfaction has been suggested. SUMMARY: To better respond to cancer patients' health care needs, various strategies focusing on doctor-patient communication have been developed. Addressing patients' overall needs and sharing complex information in an emotionally charged context and under time constraints is a daily challenge for the oncology clinician, resulting often in cancer patients' dissatisfaction. Recent interventions elaborated to facilitate doctor-patient communication in oncology focus on patients, such as handing out of videos or written preparatory information; on doctors, such as patients' self-rating feedback to doctors or communication skills trainings; or on both, such as the audiotaping of the consultation or the provision of decision aids. Although these strategies offer promising results, further research should be implemented to assess their appropriateness across sociocultural contexts and their long-term effectiveness in clinical practice.

Clinical Competence↗