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PubMed1996

Performance of healthy subjects and patients with resection from the anterior temporal lobe on matched tests of verbal and visuoperceptual learning.

We examined the equivalence of three matched forms of the Rey Auditory Verbal Learning Test (RAVLT) and three parallel forms of a new nonverbal analog, the Aggie Figures Learning Test (AFLT). One hundred and fourteen healthy subjects, primarily college students, were administered corresponding forms of the two tasks. For both tasks the three forms proved to be well-matched; as well, overall performance on the RAVLT was comparable to that on the AFLT. The two tasks were also administered to 23 patients with anterior resection from the left or right temporal lobe (ATL). Findings showed that right ATL patients were significantly impaired on the learning trials of the AFLT as compared to their learning on the RAVLT; they showed little forgetting of figures or words over a 20-min delay interval. By contrast, left ATL patients showed severe forgetting of words as compared to figures, but their learning curve for the RAVLT did not differ from that on the AFLT.

Adolescent↗
PubMed2003

Laparoscopic and robotic surgical training in urology.

The most important change in urology during the past decade was the development of minimally invasive surgery, particularly laparoscopy. However, the main drawback of laparoscopy is a steep learning curve, which results from the significant changes in the surgical environment. Although laparoscopy can provide important advantages for the patient, including decreased length of hospitalization, decreased analgesic requirement, and a shortened postoperative convalescence, one concern has been whether laparoscopic techniques should be learned solely in the operating room. For example, sports, music, and aviation are practiced before an actual performance is ever undertaken. In this review, the advantages and limitations of all available training modalities in minimally invasive surgery are described. Testing basic laparoscopic skills on inanimate models, becoming familiar with the principles of dissection and hemostasis on living animals, and studying surgical anatomy on cadavers should be considered as indispensable and complementary elements for laparoscopic training in the future. In addition, telementoring with the help of modern image processing and virtual reality eventually may become the basis of tomorrow's surgical instruction.

Clinical Competence↗
PubMed1995

Effects of reward and response costs on inhibition in ADHD children.

This study examined effects of reward and response costs on the ability of 19 attention-deficit hyperactivity disorder (ADHD) and 17 control children to inhibit responding. Children were tested under 4 reinforcement conditions on a go/no-go learning task developed by J. P. Newman, C. S. Widom, and S. Nathan (1985). Two conditions involved both reward and response costs. 1 response costs only, and 1 reward only. ADHD children made more commission errors than controls across the 4 conditions. Analyses of learning curves indicated that group differences became larger on later trials. Thus, impaired inhibition was more generalized in ADHD children than in the psychopaths and extraverts studied by Newman and colleagues, and it became most evident when the children were required to improve learning across trials.

Attention Deficit Disorder with Hyperactivity↗
PubMed2006

A meta-analysis of the training effectiveness of virtual reality surgical simulators.

The increasing use of virtual reality (VR) simulators in surgical training makes it imperative that definitive studies be performed to assess their training effectiveness. Indeed, in this paper we report the meta-analysis of the efficacy of virtual reality simulators in: 1) the transference of skills from the simulator training environment to the operating room, and 2) their ability to discriminate between the experience levels of their users. The task completion time and the error score were the two study outcomes collated and analyzed in this meta-analysis. Sixteen studies were identified from a computer-based literature search (1996-2004). The meta-analysis of the random effects model (because of the heterogeneity of the data) revealed that training on virtual reality simulators did lessen the time taken to complete a given surgical task as well as clearly differentiate between the experienced and the novice trainees. Meta-analytic studies such as the one reported here would be very helpful in the planning and setting up of surgical training programs and for the establishment of reference 'learning curves' for a specific simulator and surgical task. If any such programs already exist, they can then indicate the improvements to be made in the simulator used, such as providing for more variety in their case scenarios based on the state and/or rate of learning of the trainee.

Computer Simulation↗
PubMed1995

Indirect learning of event sequences: the effects of divided attention and stimulus continuity.

In a serial reaction time (SRT) task, the learning curve is sleeper when the stimuli are presented in a repeating sequential manner rather than in random order (Nissen & Bullemer, 1987). This is true even when subjects report being unaware of the presence of the repeating sequence. The present study examines the nature of this learning under conditions designed to reduce attentional resources and to disrupt the continuity of stimuli. In the first three experiments, subjects were trained in the SRT task, with or without the addition of a secondary tone counting task, and with repeating or non-repeating sequences. The results suggest that some sequence learning occurred despite the presence of a secondary task. Experiment 4 examined the extent of sequence learning when the inter-stimulus interval was varied between trials. The overall results suggest that despite reduced attentional allocation and discontinuous stimulus presentation, some sequence learning occurs. This result supports other work suggesting a dissociation between learning when measured explicitly, and when assessed through performance indicators.

Adult↗
PubMed2005

Origins of group coordination: nonlinear dynamics and the role of verbalization.

Coordination occurs when two or more people do the same or complimentary tasks simultaneously; its explanation game theory, nonlinear dynamics, and implicit learning theory. In the experiment, 12 four-person groups were allowed to discuss the coordination (card game) task while performing it; 12 other groups worked nonverbally. One to three group members were replaced during the game. Split-plot ANOVA showed that verbalizing groups performed better than nonverbalizing groups overall and showed more acute coordination learning curves, but verbalization did not compensate for the replacement of personnel. Groups that changed one or two players showed positive coordination transfer, but groups that changed three players did not. Nonlinear regression for temporal dynamics within verbalizing and nonverbalizing groups showed asymptotic stability for initial coordination learning and transfer to a difficult rule, a chaotic function when replacements were introduced, and asymptotic stability again when the team with replacements switched to the difficult rule.

Cooperative Behavior↗
PubMed2000

HIV/AIDS managed care program.

Approximately one-half of all patients with HIV infection who are under care have Medicaid as the third party payor. Unlike Medicare, Medicaid is a state-specific program that has huge variations in reimbursement strategies. Multiple studies have shown that care for persons with AIDS is about $20,000/year, but reimbursement through various state Medicaid programs varies about $100/m/m to $2800/m/m despite the fact that expectations for care are identical. Hopkins has a major commitment to persons with HIV infection with a program that now includes 30 faculty members and a support staff of 170. With the introduction of mandatory managed care for Medicaid recipients in July, 1997, we were confronted with the issue of substantial downsizing with abandonment of over half of our patients, or learning the transition to managed care. This has been a steep learning curve involving negotiations with the state Medicaid office, reorganization of our clinic, careful scrutiny of our database regarding resource utilization and cost, education of providers, and longitudinal collection of new information and integration of the rapid changes in the field. In the process of this transition, we learned that there are precious few resources to provide guidance and that there is a perceived need for assistance by HIV providers throughout the country. Consequently, we have now established the "HIV Managed Care Network" with substantial funding from diverse sources to support education, data collection, and public policy review. It is premature to evaluate performance since most of these activities have just begun, but we expect that this Network will serve as a demonstration model for methods to deal with chronic diseases under managed care.

Acquired Immunodeficiency Syndrome↗
PubMed2006

Biomechanical assessment and treatment in lower extremity prosthetics and orthotics: a clinical perspective.

Biomechanical treatment is like a jigsaw puzzle with two complex counterparts having many pieces. The physical and mechanical components are equally important and cannot be separated from each other. The patient with a prosthesis or an orthosis represents a biomechanical system; total treatment is essential. All of the pieces to the puzzle must be used to complete the picture. Given the present structure of the educational system, there is a separation of disciplines necessary to provide one truly biomechanical treatment. Physical therapists are educated in the bio aspect of treatment, whereas prosthetists/orthotists are educated in the mechanical aspect. Biomechanical treatment requires the direct interaction and integration of the two disciplines. Physical therapists and prosthetists/orthotists need each other. One without the other can provide only half of the treatment necessary for optimal outcomes. The patient needs both. Physical therapists need to become more familiar with mechanical treatment and learn how to integrate this into their physical treatment program. Prosthetists/orthotists must become more familiar with the importance of physical treatment and the internal corrective forces necessary for efficient ambulation. The traditional label of orthotics and prosthetics and related technology as products must be replaced with biomechanical treatment that includes orthotics and prosthetics services. Professionals working with each other is a positive step, but they need to be working together as a team toward a common goal. They need to be in the same place at the same time and work together consistently to provide total treatment. This is more than a multidisciplinary approach. It is one treatment. In this way, each benefits the other as they teach and learn simultaneously. At present, this teaching and learning can be done only on an individual basis. It is the author's hope that experienced prosthetists/orthotists and physical therapists reading this article will see the need to combine their efforts to provide truly biomechanical treatment. By working together, they can expand their present knowledge and skills. In this way, treatment and outcomes can improve and serve as the guiding force for a new generation of rehabilitation specialists. This process can be expedited through the educational system by offering advanced clinical degrees specializing in biomechanical treatment specifically designed for clinical practice rather than research, administrative, or academic positions. For this idea to become reality, educational institutions representing the physical and mechanical aspects of biomechanical treatment also must work together; this would expedite the learning curve so that it would not take so long to put the pieces of the puzzle together.

Amputation, Surgical↗
PubMed1989

Neurotrophic and behavioral effects of occipital cortex transplants in newborn rats.

Cell suspensions of embryonic occipital cortex were transplanted into newborn rats with large unilateral visual cortex lesions. When the animals were adults, they were tested on a difficult visual discrimination, and subsequently their brains were analyzed for possible neurotrophic effects of the transplants on nonvisual cortical areas which normally form connections with the occipital cortex. Behaviorally, animals with lesions and transplants learn to discriminate between columns and rows of squares at a rate which is identical to normal rats while animals with lesions and no transplants are impaired. Volume and cell-density measures show that the transplants also rescue neurons in cortical area 8 that would normally degenerate following the cortical lesion. No such neurotrophic effect of the transplants is found in cortical area 24 or area 17 contralateral to the lesion. In rats with lesions and no transplants, there is a significant correlation between the amount of area 8 remaining after the lesion and trials to criterion on the columns-rows discrimination, a relationship that does not exist in transplant animals because of their normal learning curve and the consistent sparing of area 8. Injections of HRP into the visual cortex contralateral to the lesion result in variable numbers of labeled cells within the transplant. However, there is no consistent relationship between the number of transplant cells which project to the opposite hemisphere and learning of the discrimination. It is suggested that the learning deficit following the lesion is largely attentional and that the sparing of cortical area 8 (which in rats may include the analog of the frontal eye fields present in the primate cortex) contributes to the sparing of function.

Animals↗
PubMed2005

On adaptation, maximization, and reinforcement learning among cognitive strategies.

Analysis of binary choice behavior in iterated tasks with immediate feedback reveals robust deviations from maximization that can be described as indications of 3 effects: (a) a payoff variability effect, in which high payoff variability seems to move choice behavior toward random choice; (b) underweighting of rare events, in which alternatives that yield the best payoffs most of the time are attractive even when they are associated with a lower expected return; and (c) loss aversion, in which alternatives that minimize the probability of losses can be more attractive than those that maximize expected payoffs. The results are closer to probability matching than to maximization. Best approximation is provided with a model of reinforcement learning among cognitive strategies (RELACS). This model captures the 3 deviations, the learning curves, and the effect of information on uncertainty avoidance. It outperforms other models in fitting the data and in predicting behavior in other experiments.

Adaptation, Psychological↗
PubMed2000

Ablation centration after active eye-tracker-assisted photorefractive keratectomy and laser in situ keratomileusis.

PURPOSE: To evaluate the ablation centration after active eye-tracker-assisted photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) and to investigate the effect of surgery, patient, and surgeon on the centration. SETTING: Department of Ophthalmology, China Medical College Hospital, Taichung, Taiwan, Republic of China. METHODS: This retrospective study comprised 177 eyes of 101 patients: 16 eyes had PRK and 161, LASIK. All laser treatments were performed with the aid of an eye tracker. The amount of decentration was analyzed by corneal topography. The factors influencing centration were divided into surgery related (PRK/LASIK), patient related (low/high myopia and effect of learning), and surgeon related (learning curve). RESULTS: The mean decentration was 0.33 mm in PRK eyes and 0.35 mm in LASIK eyes. For the surgery-related factor, there was no significant difference between the PRK and LASIK eyes. For the patient-related factors, centration was better in the second eye (effect of learning) and decentration was more severe in eyes with high myopia (low/high myopia). For the surgeon-related factor, there was no significant difference between eyes that had the first 50 LASIK procedures and those that had the last 50 procedures. CONCLUSIONS: An eye tracker, which makes the laser beam follow the eye's movements, helps to avoid severe decentration. This study showed, however, that an active eye-tracking system alone cannot ensure good centration. Patient cooperation and fixation are important.

Cornea↗
PubMedDate not supplied

Analysis of methods to assess frontal sinus extent in osteoplastic flap surgery: transillumination versus 6-ft Caldwell versus image guidance.

BACKGROUND: The aim of this study was to compare three common methods (transillumination, plain radiographs, and computerized tomography [CT] image guidance) for estimating the position and extent of pneumatization of the frontal sinus in osteoplastic flap surgery. METHODS: Axial CT scans and 6-ft Caldwell radiographs were performed on 10 cadaver heads. For each head, soft tissue overlying the frontal bone was raised and the anticipated position and extent of the frontal sinus at four points was marked using three common methods. The silhouette of the frontal sinus from the Caldwell plain radiograph was excised and placed in position. Four points at the periphery also were made using information obtained from a passive optically guided image-guided surgery device, and transillumination via a frontal trephination also was used to estimate sinus extent. The true sinus size was measured at each point and compared with experimental values. RESULTS: The use of CT image guidance generated the least difference between measured and actual values (mean = 1.91 mm; SEM = 0.29); this method was found statistically superior to Caldwell (p = 0.040) and transillumination (p = 0.007). Image guidance did not overestimate the size of the sinus (0/36) and was quicker than the Caldwell approach (8.5 versus 11.5 minutes). There was no learning curve appreciated with image guidance. CONCLUSION: Accurate and precise estimation of the position and extent of the frontal sinus is crucial when performing osteoplastic flap surgery. Use of CT image guidance was statistically superior to Caldwell and transillumination methods and proved to be safe, reproducible, economic, and easy to learn.

Cadaver↗
PubMed2005

Fluctuation-dissipation theorem and models of learning.

Advances in statistical learning theory have resulted in a multitude of different designs of learning machines. But which ones are implemented by brains and other biological information processors? We analyze how various abstract Bayesian learners perform on different data and argue that it is difficult to determine which learning-theoretic computation is performed by a particular organism using just its performance in learning a stationary target (learning curve). Based on the fluctuation-dissipation relation in statistical physics, we then discuss a different experimental setup that might be able to solve the problem.

Animals↗
PubMed2005

Aging and longitudinal change in perceptual-motor skill acquisition in healthy adults.

Knowledge about aging of perceptual-motor skills is based almost exclusively on cross-sectional studies. We examined age-related changes in the retention of mirror-tracing skills in healthy adults who practiced for 3 separate days at baseline and retrained 5 years later at follow-up. Overall, the speed and accuracy of an acquired skill were partially retained after a 5-year interim, although the same asymptote was reached. Analyses with individual learning curves indicated that the effects of age on mirror-tracing speed were greater at longitudinal follow-up than at baseline, with older adults requiring more training to reach asymptote. Thus, although the long-term retention of acquired skills declines with age, older adults still retain the ability to learn the skill. Moreover, those who maintained a processing speed comparable with that of the younger participants evidenced no age-related performance decrements on the mirror-drawing task.

Adult↗
PubMed2004

Finding the way: a model for educational system analysis.

Administrators new to an academic setting experience a steep learning curve in finding their way around the organization. Leadership strategies that have proven effective in a previous setting or in another role may not be appropriate to or effective in the new setting. Disruptive effects of such leadership transitions can be minimized if newly employed administrators take a systematic approach to learning about the organization. The educational systems analysis model (ESAM) described here provides direction for new academic administrators in rapid analysis of a nursing education program. ESAM is comprised of both external and internal elements that influence system operation and the role of the administrator within the system. External elements include environmental factors that influence the program as well as the community of interest. Internal elements include the mission and goals, culture, relationships, structure, programs and services, resources, and outcomes of the program. Each of the internal elements is considered from both content and process perspectives. Relationships among the elements in the model are dynamic and reciprocal.

Administrative Personnel↗
PubMed2006

Sex determines the neurofunctional predictors of visual word learning.

This study used functional MRI and an artificial language training paradigm to explore sex differences in the processing of a new writing system and how sex determines the optimal neural resource recruitment for visual word learning. Results indicated that males and females achieved equal learning outcome, and their learning curve followed a similar power function. They also showed similar overall activation in the fusiform cortex, a region that has been associated with visual word processing. Despite the absence of sex differences in averaged behavioral performance and neural activation, males and females were found to have different neural predictors of visual word learning. As predicted, left-lateralized fusiform activation predicted visual word learning for males, but not for females, whereas bilateral fusiform activation predicted visual word learning for females, but not males. These results suggest that male and female brains operate differently to achieve the best performance in visual word learning. The individual-differences approach adopted in the present study provides a new and useful perspective to sex differences.

Adult↗
PubMed1968

Successive reversals of a classically conditioned heart-rate discrimination.

Rats were trained to criterion in successive reversals of a classically conditioned heart-rate discrimination. Criterion was attained more rapidly in the later reversals in the series than in the early reversals and the inter-problem learning curve was of the same general form as that found with successive instrumental discrimination reversal in the same species.

Animals↗