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At least 163 records · Page 9Linked to original sources

High level of dexterity: differential contributions of frontal and parietal areas.

In the present functional magnetic resonance imaging experiment, study participants performed a dynamic tracking task in a precision grip configuration. The precision level of the force control was varied while the mean force level of 5 N was kept constant. Contrasts cancelling error rate differences between the conditions showed activation of nonprimary motor areas and other frontal structures in response to increasing precision constraints when the precision of force control could still be increased, and of right primary and associative parietal areas when the precision of the produced force control reached its maximum. These results suggest that the network of frontal and parietal areas, usually working together in fine control of dexterity tasks, can be differentially involved when environmental constraints become very high.

Brain Mapping↗

Surgical dexterity after a 'night out on the town'.

BACKGROUND: This study examines the effect of alcohol intake on surgical dexterity immediately after and the morning after alcohol intake and minimal sleep deprivation by simulating a typical night out on the town. METHODS: Five surgeons (all men, aged 31-40 years) were trained on a laparoscopic surgical simulator (minimally invasive surgical trainer-virtual reality) to reach a desired standard of performance. Three experimental settings were used: (i) a control night with no alcohol and full night's sleep; (ii) a sham night out (sleep deprived) without alcohol; and (iii) a night out with alcohol ad libitum. The parameters recorded were the average time taken to carry out a task, error rate, average diathermy time and diathermy (damage) time to main object. Comparisons between baseline readings, those in the middle of the night and those of the following morning were made by applying ANOVA methods after logarithmic transformation of the data. RESULTS: The candidates consumed, on average, 10.33 units (range, 6-15 units) of alcohol and had 0.86% (range, 0.71-1.1%) of breath alcohol levels and an average of 3.75 h (range, 3-5 h) of sleep after a typical night out. The morning-after breath alcohol levels were 0%. There was significant deterioration in performance, as measured by all indicators, immediately after alcohol consumption. The adverse effects on time taken to complete the task and total diathermy time were still apparent the morning after. The sham night out appeared to affect only 'time parameters'. No significant changes in performance were seen in the control setting. CONCLUSION: Both alcohol consumption and sleep deprivation adversely affect the ability to carry out surgical procedures. Our simulation study suggests that the adverse effects of alcohol intake persist the following morning.

Alcohol Drinking↗

The maturation of motor dexterity: or why Johnny can't go any faster.

The speed of alternating movements at the ankle, metacarpophalangeal and wrist joints in 11 healthy children and 13 adults doubled between age 3 and 11 years, despite a 32-fold increase in limb-segment inertia produced by the doubling in limb length over the same period. The data for the children showed little or no practice effect. The speeds for the adults, though faster than those for the children, were more widely dispersed, indicating the possibility that training might increase the speed of the slowest adult. The findings are consistent with a previous report demonstrating a parallel increase in the speed of calf muscles over the first 10 years of life and it is inferred that the increase in dexterity at the wrist and metacarpophalangeal joints also depends on an increase in muscle speed with age. Muscle maturation may impose a rate-limiting envelope for all motor tasks which is particularly evident in rapidly alternating movements. These findings have implications for training in sport and music and for the understanding of motor delay, clumsiness and speech difficulties.

Adult↗

Effect of tutorial input in addition to augmented feedback on manual dexterity training and its retention.

Virtual reality (VR) simulators can be used as tools in manual dexterity training. The visual feedback guides the subject towards proper performance but creates, at the same time, some dependency on this feedback. To overcome this drawback, the effect of adjunct tutorial input on motor learning behaviour was examined. Novice dental students were randomly assigned to one of two training groups or to a non-training control group, given the task of preparing a geometrical class 1 cavity in phantom teeth. The feedback (FB) group trained under augmented visual feedback conditions, provided by the VR system (DentSim). The feedback-plus (FB+) group received, in addition, standardised expert input to enrich the augmented feedback information. The control group, consisting of same year students, did not participate in any training programme. All preparations were evaluated by the VR scoring system. Performance analyses revealed an overall trend towards significant improvement with practice for the training groups. Performance of the FB+ group was most accurate across training. After 1 day and 3 weeks of no practice, both training groups outperformed the control group. After 4 months, however, only the FB+ condition was significantly more accurate than the control group. The same tendency was noted for the transfer tests. Consequently, cavity preparation experience on a VR system under the condition of frequently provided feedback supplemented with expert input was most beneficial to long time learning.

Computer Simulation↗

Management of cor triatriatum dexter by balloon dilatation in three dogs.

Two dogs, one immature and one adult, were presented with a history of progressive ascites. In a third, immature dog, increasing exercise intolerance had been noted. Echocardiography demonstrated a partition in the right atrium (cor triatriatum dexter) and echocontrast studies documented normal flow from the cranial vena cava into the right atrium and ventricle. A saphenous vein contrast study demonstrated flow from the caudal vena cava into an accessory right atrial chamber (sinus venarum). The sinus venarum communicated with the true right atrium via a small defect in the atrial membrane in one dog, and additionally with the left atrium via a right-to-left shunting foramen ovale in the other dogs. All defects were visualised on angiographic studies by selective catheterisation of the caudal vena cava via the femoral vein. Balloon dilatation of the defect was then performed using a small followed by a larger balloon angioplasty catheter to enlarge the defect in the atrial membrane. Clinical signs improved within days and were sustained in the long-term in all cases.

Animals↗

Diagnosis and management of cor triatriatum dexter in a Pyrenean mountain dog and an Akita Inu.

Cor Triatriatum Dexter is a rare, congenital cardiac defect in which the right atrium is partitioned into two compartments, effectively creating a triatrial heart. The clinical signs exhibited by the patient usually relate to impeded venous return via the caudal vena cava. The two dogs in this report both displayed ascites from a young age and grew poorly. In both cases the diagnosis was made during echocardiographic examination and was confirmed by angiography. Both dogs were successfully treated by resection of the partitioning membrane within the right atrium, using hypothermia and inflow occlusion to achieve a clear surgical field. Both dogs recovered well, their clinical signs resolved and they have grown to normal adult size.

Animals↗

Regression analysis of dexterity tests and dental students' practical examination results.

The desirability of some means of assessing potential dental students' dexterity is discussed and three new practical tests are described. Regression analysis was performed on the results and the subsequent correlations are presented. Further regression analysis was performed on examiners' scores in dental technology showing the inconsistencies. Results were not conclusive and it seems that the tests could possibly be used in an advisory role but little more.

Aptitude Tests↗

Cor triatrium dexter.

A case of cor triatrium dexter is described in which the patient had been independently assessed in two cardiological centres as having a form of Ebstein's anomaly. The differential diognosis is discussed.

Adult↗

Cor triatriatum dexter with imperforate Ebstein's anomaly.

A case of cor triatriatum dexter is described in which the anomalous right atrial partition is identified as the right venous valve; there is an associated anomaly of the right atrioventricular valve which combines features of Ebstein's anomaly, and an atypical, imperforate, tricuspid atresia.

Abnormalities, Multiple↗

Doppler-ultrasonographic detection of retrograde pulsatile flow in the caudal vena cava of a puppy with cor triatriatum dexter.

A three-month-old puppy had ascites, but its heart was normal by auscultation. Abdominal ultrasonography revealed an enlarged liver, distended hepatic veins and a distended caudal vena cava. Doppler ultrasonography detected retrograde flow in the caudal vena cava and abnormally pulsatile flow in the hepatic veins and caudal vena cava. A non-selective venogram was used to detect the path of the blood from the caudal vena cava. A postmortem examination showed that the puppy had cor triatriatum dexter and a defect in the atrial septum.

Animals↗

Artificial ear: A training tool for grommet insertion and manual dexterity.

Under European Working Time Directives, surgical trainees now have to attempt to gain adequate operative experience within newly-restricted working hours. Surgical skills training must therefore increasingly occur outside theatre and away from real patients, in a simulated environment. In ENT, we suggest that instruction and practice of grommet insertion may be greatly facilitated through the use of an artificial ear model, which can be assembled cheaply and quickly. Our 'ear' may also be used for manual dexterity exercises, which have the potential to be developed into validated tests of core ENT surgical skills in the future.

Clinical Competence↗

[Box and block test of manual dexterity in normal subjects and in patients with multiple sclerosis].

Recently new disease-modifying treatments for multiple sclerosis (MS) were introduced which can change the natural course of the disease. In clinical trials with these new agents the Expanded Disability Status Scale (EDSS) is often used as a primary outcome instrument to measure neurological impairment and disability. A number of limitations have been identified when using the EDSS, some of wich are because the EDSS is an ordinal scale that is heavily biased to locomotor function. In this study we applied the box and block test of manual dexterity in normal subjects and relapsing-remitting MS patients. The results were that 64.8% of the female and 80.7% of the male patients had significant changes on this task compared with normal subjects, and as this test is easily applied and is sensitive in detecting upper extremity functional ability, we recommend its use in clinical trials to evaluate new drugs in MS patients.

Adolescent↗

Characterization of the adherent cells developed in Dexter-type long-term cultures from human umbilical cord blood.

We have previously shown that when human umbilical cord blood (UCB) cells are cultured in standard Dexter-type long-term cultures (D-LTC), adherent cells develop forming a discrete net on the bottom of the culture flask. The identity of such cells, however, has not been defined. Accordingly, the major goal of the present study was to characterize the adherent cells developed in standard UCB D-LTC. Cultures were established from 14 UCB samples and from nine bone marrow (BM) samples, as controls. Both UCB and BM cultures were initiated with the same number of mononuclear cells (MNC) (2.5 x 10(6) MNC/ml). After three weeks in culture, adherent cell numbers in UCB D-LTC were 24%-30% of the numbers found in BM cultures. More than 90% of the adherent cells in UCB D-LTC expressed the acid phosphatase enzyme, whereas no alkaline phosphatase-positive cells were observed. This was in contrast to BM D-LTC, in which alkaline and acid phosphatase were expressed by 60%-75% and 20%-45% of the adherent cells, respectively. Immunochemical analysis showed that CD61 (osteoclast marker) and Factor VIII (endothelial cell marker) were not expressed by the adherent cells developed in UCB cultures. Interestingly, the majority of such cells expressed CD1a (dendritic cell marker), CD14, CD68 and CD115 (antigens mainly expressed by macrophagic cells). When the cultures were supplemented with the recombinant cytokines epidermal growth factor, basic fibroblast growth factor, platelet-derived growth factor or granulocyte-macrophage colony-stimulating factor (GM-CSF), only GM-CSF had a significant positive effect on adherent cell number. In order to test for some functional properties of the adherent cells developed in culture, production of stem cell factor (SCF), interleukin 6 (IL-6) and tumor necrosis factor-alpha (TNF-alpha) was assessed. IL-6 and TNF-alpha showed elevated levels in UCB D-LTC, whereas SCF levels were always below detection. Finally, analysis of fibroblast progenitors (fibroblast colony-forming units [CFU-F]) showed that these cells were present in BM samples (6 CFU-F/10(5) MNC) and were totally absent in UCB samples. Taken together, the results of the present study indicate that the vast majority of the adherent cells developed in standard UCB D-LTC belong to the macrophage lineage and that fibroblasts seem to be absent. Interestingly, the high proportion of CD1a+ cells suggests that dendritic cells are also present in these cultures.

Cell Adhesion↗

Adult norms for the Box and Block Test of manual dexterity.

The Box and Block Test, a test of manual dexterity, has been used by occupational therapists and others to evaluate physically handicapped individuals. Because the test lacked normative data for adults, the results of the test have been interpreted subjectively. The purpose of this study was to develop normative data for adults. Test subjects were 628 Normal adults (310 males and 318 females) from the seven-county Milwaukee area. Data on males and females 20 to 94 years old were divided into 12 age groups. Means, standard deviations, standard error, and low and high scores are reported for each five-year age group. These data will enable clinicians to objectively compare a patient's score to a normal population parameter.

Adult↗

Muscle power, dexterity skill and visual perception in community home girls trained in yoga or sports and in regular school girls.

The present study was conducted to compare critical flicker fusion frequency (CFF), degree of optical illusion ("di"), dexterity scores, and grip strength in three groups of subjects, viz community home girls who had learned yoga for 6 months (CHY), age-matched community home girls who had physical activity training for 6 months (CHP), and girls who were attending a regular school (SCH). There were equal numbers in each group for each of the 4 assessment (range 11 to 30 subjects) and age range was 12 to 16 years of age. The CHP group had significantly lower CFF and "di" was significantly higher (one factor ANOVA, t test for unpaired data) in the CHP group, both compared to CHY and SCH groups. Right hand grip strength was also significantly less in the CHP group compared to SCH. The results were explained by previous reports of high levels of anxiety and aggression in community-home groups, which is known to influence the four parameters described here. The better performance of the CHY group compared to CHP, suggested that yoga practice has a beneficial effect in these subjects.

Adolescent↗

Effects of visual acuity and visual motor speed and dexterity on cognitive test performance.

This study examined the hypothesis that near visual acuity and visual motor speed and dexterity contribute significantly to performance on cognitive tests that place a premium on these functions. Near visual acuity for both eyes, Finger Tapping Test - average taps with dominant hand, and Grooved Pegboard Test - dominant hand time, served as the independent variables. The dependent variables were Trail Making Test-Part B and the Performance subtests of the Wechsler Adult Intelligence Scale. Results indicated that while visual acuity was significantly correlated with all six test variables, it did not contribute to the regression model as well as Pegboard time or Tapping speed. Pegboard time and Tapping speed contributed to the regression model, but in different ways depending upon which test was examined.

Journal Article↗

The utility of Canadian DAT Perceptual Ability and Carving Dexterity scores as predictors of psychomotor performance in first-year operative dentistry.

This study sought to determine if Canadian Dental Aptitude Test Perceptual Ability (PA) and Carving Dexterity (CD) scores have any practical utility as predictors of psychomotor performance. Simple linear regression and multiple regression analyses were performed and prediction intervals plotted. Efforts were made to expand the range of the predictor and dependent variables and to improve the accuracy and consistency and prevent contamination of the dependent variables. Results for both PA and CD varied markedly across years. Weak, but statistically extremely significant, correlations were observed for both PA and CD with specific technique grades and the year-overall pooled data. PA correlations loaded on exams at the start, and CD correlations loaded on exams at the end of the year. Manual average scores exhibited the strongest correlation with year-overall technique grades, but could explain no more than 7.2 percent of observed variance. Prediction intervals for year-end grades spanned at least 38 percentage grade points for both PA and CD. Within the context of the present study, PA and CD scores demonstrated no practical utility as predictors of psychomotor performance.

Aptitude Tests↗