Referral Patterns for Endocrine Surgical Disease

ObjectiveReferrals between physician specialties are common practice, and clear patterns develop. The increasing availability of high-volume endocrine surgery subspecialists with better outcomes may change these patterns. This study aimed to determine what factors influence endocrinologists’ referral patterns for the surgical treatment of endocrine disease.MethodsA national, cross-sectional, voluntary survey of members of the American Association of Clinical Endocrinologists examined physician demographics, physician’s opinions on referral to endocrine surgery, preferred surgeon specialty, knowledge about surgeon characteristics, and how these factors influenced which surgeons they referred patients, as well as what changes in these factors would alter their referral patterns.ResultsThe survey response rate was 15% (73/500), and 97% were endocrinologists. On average, 0 to 5 patients/ week were referred for surgery. Most respondents (91.8%) felt that endocrinologists should decide which surgeon to refer. General surgery was the preferred surgeon specialty (43.7%), and endocrine surgery was the preferred subspecialty (70.8%). The factors most often cited as very important in referral to a surgeon included surgeon outcome/ complications (71%), familiarity with surgeon (65%), surgeon’s communication with referring physician (61%), and surgeon volume (59%). The factors most often cited as likely to change physician referral patterns included patient satisfaction (62%), complication rates (57%), surgeon outcomes (54%), and surgeon volume (50%). The factors most often cited as unlikely to change referral patterns included new surgeon availability (70%) and hospital/surgeon advertising (58%).ConclusionReferring physicians want experienced endocrine surgeons with high operative volumes and good outcomes whom they are familiar with. The promotion of referral to high-volume surgeons requires communication, good outcomes, and satisfied patients. (Endocr Pract. 2014;20:571-575)     

Assessment of whether in-hospital mortality for lobectomy is a useful standard for the quality of lung cancer surgery: retrospective study

Objectives To calculate in-hospital mortality after lobectomy for primary lung cancer in the United Kingdom; to explore the validity of using such data to assess the quality of UK thoracic surgeons; and to investigate the relation between in-hospital mortality and the number of procedures performed by surgeons.Design Retrospective study.Setting 36 departments dealing with thoracic surgery in UK hospitals.Participants 4028 patients who had undergone lobectomy for primary lung cancer by one of 102 surgeons.Main outcome measures In-hospital mortality in relation to individual surgeons, among all patients, and among each of five groups of patients defined by the number of operations performed by the surgeon.Results 103 patients (2.6%, 95% confidence interval 2.1% to 3.1%) died after surgery during the same hospital admission. No significant difference was found for in-hospital mortality between the five groups.Conclusions The number of procedures performed by a thoracic surgeon is not related to in-hospital mortality. Reporting data on in-hospital mortality after lobectomy for primary lung cancer is a poor tool for measuring a surgeon''s performance.     

The surgical treatment of brachial plexus injuries in adults

Posttraumatic brachial plexus palsy is a severe injury primarily affecting young individuals at the prime of their life. The devastating neurological dysfunction inflicted in those patients is usually lifelong and creates significant socioeconomic issues. During the past 30 years, the surgical repair of these injuries has become increasingly feasible. At many centers around the world, leading surgeons have introduced new microsurgical techniques and reported a variety of different philosophies for the reconstruction of the plexus. Microneurolysis, nerve grafting, recruitment of intraplexus and extraplexus donors, and local and free-muscle transfers are used to achieve optimal outcomes. However, there is yet no consensus on the priorities and final goals of reconstruction among the various centers.     

Craniofacial distraction osteogenesis: a review of 3278 cases

The nascent field of craniofacial distraction osteogenesis has not yet been subjected to a rigorous evaluation of techniques and outcomes. Consequently, many of the standard approaches to distraction have been borrowed from the experience with long bones in orthopedic surgery. The ideal "latency period" of neutral fixation, rate and rhythm of distraction, and consolidation period have not yet been determined for the human facial skeleton. In addition, because the individual craniofacial surgeon's experience with distraction has generally been small, outcomes and meaningful complication rates have not yet been published.In this study, a four-page questionnaire was sent to 2476 craniofacial and oral/maxillofacial surgeons throughout the world, asking about their experiences with distraction osteogenesis. Information about the types of cases, indications for surgery, surgical techniques, postoperative management, outcomes, and complications were tabulated. Of 274 respondents (response rate, 11.4 percent), 148 indicated that they used distraction in their surgical practice. One hundred forty-five completed surveys were entered into a database that provided information about 3278 craniofacial distraction cases. Statistical analyses were performed comparing the rates of premature consolidation, fibrous nonunion, and nerve injury, on the basis of the use of a latency period and different rates and rhythms of distraction. In addition, the rates of all complications were determined and compared on the basis of the number of distraction cases performed per surgeon.The results of the study clearly show a wide variation in the surgical practice of craniofacial distraction osteogenesis. Although the cumulative complication rate was found to be 35.6 percent, there is a pronounced learning curve, with far fewer complications occurring among more experienced surgeons (p < 0.001). The presence of inferior alveolar nerve injury as a result of mandibular distraction was much lower for respondents whose distraction regimens consisted of no more than 1 mm of distraction per day (19.5 percent versus 2.4 percent; p < 0.001). No evidence was found to support the use of a latency period or to divide the daily distraction regimen into more than one session per day. Conclusions could not be drawn from this study regarding the length of the consolidation period. Overall, the surgeon-reported outcomes are comparable with those published for other craniofacial procedures, despite the higher incidence of complications.Although conclusions made on the basis of a subjective questionnaire need to be interpreted cautiously, this study has strength in the large numbers of cases reviewed. Because of the anonymity of responses, it has been assumed that surgeons who responded to the survey reported accurate numbers of complications and successful outcomes. Finally, additional clinical and animal studies that will be of benefit in advancing the field of craniofacial distraction osteogenesis are outlined.     

Instrumental responding remains under the control of the consequent outcome after extended training

The effect of extensive training on the contribution of response--outcome learning to instrumental performance in rats was re-examined in two experiments using a transfer test. In each experiment, two discriminative stimuli were established as signals for different response--outcome combinations (e.g. light: nose poke-pellets and noise: handle pull-sucrose). Then, two different responses (lever press and chain pull) were concurrently trained with those outcomes. In Experiment 1, these responses underwent extensive training, each with a different outcome (e.g. lever press-pellets and chain pull-sucrose). In Experiment 2, these responses were trained moderately with one outcome (e.g. lever press-pellets and chain pull-sucrose) and extensively with a different outcome (e.g. lever press-sucrose and chain pull-pellets). Finally, transfer tests were conducted in which the discriminative stimuli, noise and light, were tested periodically with the lever and chain. In Experiment 1, the stimuli consistently and preferentially elevated performance of the response trained with the same outcome relative to that trained with a different outcome. In Experiment 2, the stimuli elevated both responses nondifferentially. However, a drive manipulation (thirst) designed to increase the value of sucrose relative to pellets revealed a significant preference for the response that had been extensively trained with sucrose. Overall, the results of these experiments confirm previous findings that instrumental behaviors do not become increasingly independent of their consequent outcomes with extended training. However, the transfer results of Experiment 2 highlight a potential limitation of the transfer test for assessing variations in the strength of R--O associations.     

Volume of procedures and risk of recurrence after repair of groin hernia: national register study

Objective To determine whether the association between volume and outcome found in major surgery also holds true for a minor operation.Design Review of outcomes after hernia surgery in Sweden.Setting Surgical units registered with the Swedish hernia register, which in 2004 covered about 95% of all hernia operations in Sweden.Participants 86 409 patients over 15 years, who underwent 96 601 unilateral or bilateral groin hernia repairs (94 077 inguinal and 2524 femoral) in 1996-2004 at the participating surgical units.Main outcome measure Re-operation for recurrence.Results There was a significantly higher rate of re-operation in surgeons who carried out 1-5 repairs a year than in surgeons who carried out more repairs. There was no association between outcome and further increases in volume. Although about half of surgeons in Sweden who repair hernias are low volume operators, they performed only 8.4% of all repairs.Conclusions Sweden’s numerous low volume hernia surgeons perform such a small proportion of all operations that the impact of their inferior results on the nationwide re-operation rate is minimal. Volume indicates an approximate minimum value for the number of hernia repairs a surgeon should do each year but the outcome in surgeons who carry out more than that number disqualifies volume as an indicator of proficiency.     

Effect of the passage of time on the contribution of initial response-outcome associations to instrumental performance

The effect of the passage of time on the contribution of initial response-outcome associations to subsequent instrumental performance was explored in three experiments with rats using outcome devaluation. Experiments 1 and 2 showed that a response that had been trained first with one outcome and then given identical training with a second outcome was more sensitive to devaluation of the second outcome than the first if the two training episodes were separated in time. Experiment 3 showed that inserting a delay between training with the second outcome and testing after outcome devaluation appeared to mitigate this effect of temporally separating first and second outcome training. Inserting this delay also made a response slightly more sensitive to devaluation of the first outcome than the second when there was no delay between the two training episodes. These results suggest that the passage of time can shift the balance between the contributions of first and second trained outcomes to instrumental performance.     

Identification of surgeon–individual treatment profiles to support the provision of an optimum treatment service for cataract patients

One objective of ophthalmological departments is the optimization of patient treatment services. A strategy for optimization is the identification of individual potential for advanced training of surgeons based on their daily working results. The objective of this feasibility study was the presentation and evaluation of a strategy for the computation of surgeon–individual treatment profiles (SiTPs). We observed experienced surgeons during their standard daily performance of cataract procedures in the Ophthalmological Department of the University Medical Center Leipzig, Germany. One hundred five cases of cataract procedures were measured as Surgical Process Models (SPMs) with a detailed-to-the-second resolution. The procedures were performed by three different surgeons during their daily work. Subsequently, SiTPs were computed and analyzed from the SPMs as statistical ‘mean’ treatment strategies for each of the surgeons. The feasibility study demonstrated that it is possible to identify differences in surgeon–individual treatment profiles beyond the resolution of cut–suture times. Surgeon–individual workflows, activity frequencies and average performance durations of surgical activities during cataract procedures were analyzed. Highly significant (p < 0.001) workflow differences were found between the treatment profiles of the three surgeons. Conclusively, the generation of SiTPs is a convenient strategy to identify surgeon–individual training potentials in cataract surgery. Concrete recommendations for further education can be derived from the profiles.     

Total Hip Arthroplasty: Direct Anterior Approach Versus Posterior Approach in the First Year of Practice

BackgroundThe direct anterior approach (DAA) for total hip arthroplasty (THA) has been popularized as a less invasive technique, however outcomes within the first year of practice after fellowship have not been investigated. The primary aim was to determine differences in complications and outcomes between DAA and posterior approach (PA) in the first year of practice. The secondary aim was to determine if there was a learning curve factor in DAA and PA after fellowship training.MethodsTHA cases performed by two surgeons during their first year of practice were reviewed. Overall, 181 THAs (91 DAA, 90 PA) in 168 patients, were performed. Intraoperative differences (blood loss, operative time), hospital stay, complications, reoperations, and revisions were compared.ResultsOverall surgical complications were similar between DAA and PA (11% vs. 9%, p=0.64), but complication profiles were different: dislocation (1% vs. 4%, p=0.17), intraoperative femoral fracture (2% vs. 1%, p=0.32), postoperative periprosthetic fractures (2% vs. 3%, p=0.64). neuropraxia (3% vs. 0%, p=0.08). There was no difference in rate of reoperation (1% vs. 3%, p=0.31). There was a difference in rate of revision at final follow-up (0% vs. 6%, p=0.02). DAA consisted of longer operative time (111 vs. 99 minutes; p<0.001), however was only significant in the first 50 cases (p<0.001), while the subsequent cases were similar (p=0.31). There was no difference in the first 50 cases compared to the subsequent cases for either approach regarding blood loss, complications, reoperations, or revisions.ConclusionDAA and PA for THA performed within the first year of practice exhibit similarly low complication rates, but complication profiles are different. In our series, PA did demonstrate a higher risk of revision at final follow-up. A learning curve is not unique to the DAA. Both DAA and PA THA exhibited a learning curve in the first 50 cases performed at the start of a surgeon’s practice. Level of Evidence: III     

Machine learning algorithms based on signals from a single wearable inertial sensor can detect surface- and age-related differences in walking

The aim of this study was to investigate if a machine learning algorithm utilizing triaxial accelerometer, gyroscope, and magnetometer data from an inertial motion unit (IMU) could detect surface- and age-related differences in walking. Seventeen older (71.5 ± 4.2 years) and eighteen young (27.0 ± 4.7 years) healthy adults walked over flat and uneven brick surfaces wearing an inertial measurement unit (IMU) over the L5 vertebra. IMU data were binned into smaller data segments using 4-s sliding windows with 1-s step lengths. Ninety percent of the data were used as training inputs and the remaining ten percent were saved for testing. A deep learning network with long short-term memory units was used for training (fully supervised), prediction, and implementation. Four models were trained using the following inputs: all nine channels from every sensor in the IMU (fully trained model), accelerometer signals alone, gyroscope signals alone, and magnetometer signals alone. The fully trained models for surface and age outperformed all other models (area under the receiver operator curve, AUC = 0.97 and 0.96, respectively; p ≤ .045). The fully trained models for surface and age had high accuracy (96.3, 94.7%), precision (96.4, 95.2%), recall (96.3, 94.7%), and f1-score (96.3, 94.6%). These results demonstrate that processing the signals of a single IMU device with machine-learning algorithms enables the detection of surface conditions and age-group status from an individual’s walking behavior which, with further learning, may be utilized to facilitate identifying and intervening on fall risk.     

Touchscreen-Based Cognitive Tasks Reveal Age-Related Impairment in a Primate Aging Model,the Grey Mouse Lemur (Microcebus murinus)

Mouse lemurs are suggested to represent promising novel non-human primate models for aging research. However, standardized and cross-taxa cognitive testing methods are still lacking. Touchscreen-based testing procedures have proven high stimulus control and reliability in humans and rodents. The aim of this study was to adapt these procedures to mouse lemurs, thereby exploring the effect of age. We measured appetitive learning and cognitive flexibility of two age groups by applying pairwise visual discrimination (PD) and reversal learning (PDR) tasks. On average, mouse lemurs needed 24 days of training before starting with the PD task. Individual performances in PD and PDR tasks correlate significantly, suggesting that individual learning performance is unrelated to the respective task. Compared to the young, aged mouse lemurs showed impairments in both PD and PDR tasks. They needed significantly more trials to reach the task criteria. A much higher inter-individual variation in old than in young adults was revealed. Furthermore, in the PDR task, we found a significantly higher perseverance in aged compared to young adults, indicating an age-related deficit in cognitive flexibility. This study presents the first touchscreen-based data on the cognitive skills and age-related dysfunction in mouse lemurs and provides a unique basis to study mechanisms of inter-individual variation. It furthermore opens exciting perspectives for comparative approaches in aging, personality, and evolutionary research.     

Clinical Efficacy of Simulated Vitreoretinal Surgery to Prepare Surgeons for the Upcoming Intervention in the Operating Room

Purpose

To evaluate the efficacy of the virtual reality training simulator Eyesi to prepare surgeons for performing pars plana vitrectomies and its potential to predict the surgeons’ performance.

Methods

In a preparation phase, four participating vitreoretinal surgeons performed repeated simulator training with predefined tasks. If a surgeon was assigned to perform a vitrectomy for the management of complex retinal detachment after a surgical break of at least 60 hours it was randomly decided whether a warmup training on the simulator was required (n = 9) or not (n = 12). Performance at the simulator was measured using the built-in scoring metrics. The surgical performance was determined by two blinded observers who analyzed the video-recorded interventions. One of them repeated the analysis to check for intra-observer consistency. The surgical performance of the interventions with and without simulator training was compared. In addition, for the surgeries with simulator training, the simulator performance was compared to the performance in the operating room.

Results

Comparing each surgeon’s performance with and without warmup trainingshowed a significant effect of warmup training onto the final outcome in the operating room. For the surgeries that were preceeded by the warmup procedure, the performance at the simulator was compared with the operating room performance. We found that there is a significant relation. The governing factor of low scores in the simulator were iatrogenic retinal holes, bleedings and lens damage. Surgeons who caused minor damage in the simulation also performed well in the operating room.

Conclusions

Despite the large variation of conditions, the effect of a warmup training as well as a relation between the performance at the simulator and in the operating room was found with statistical significance. Simulator training is able to serve as a warmup to increase the average performance.     

毒性多结节性甲状腺肿的手术术式探讨

目的:探讨毒性多结节性甲状腺肿的手术切除范围,为临床手术治疗毒性多结节性甲状腺肿提供理论依据。方法:收集2006年12月至2011年12月哈尔滨医科大学附属第一临床医学院普外科确诊且进行手术的52例双侧毒性多结节性甲状腺肿患者的临床资料,并按照术式分为次全切除组(24例)和近全/全切除组(28例)。术后通过病理检查观察其合并甲状腺癌的情况,临床观察其是否出现声音嘶哑(喉返神经损伤)和低钙血症(甲状旁腺损伤)情况,并随访患者甲状腺结节和(或)甲状腺功能亢进的复发情况。结果:次全切除组甲状腺癌的检出率为4.2%(1/24),近全/全切除组检出率为7.1%(2/28),两者比较差异无统计学意义(x2=0.02,P0.05);两组患者术后暂时性声音嘶哑发生率分别为4.2%(1/24)、3.6%(1/28),差异无统计学意义(x2=0.37,P0.05),术后暂时性低钙血症发生率分别为4.2%(1/24)、7.1%(2/28),差异亦无统计学意义(x2=0.02,P0.05)。近全/全切除组患者术后无甲状腺结节和(或)甲状腺功能亢进复发,次全切除组患者有5例复发,复发率为20.8%(5/24),两组比较差异有统计学意义(x2=4.28,P0.05)。结论:甲状腺近全/全切除术比次全切除术更能减少毒性多结节性甲状腺肿的复发。     

Variation in management of small invasive breast cancers detected on screening in the former south east Thames region: observational study.

OBJECTIVE: To examine the variation in surgical and adjuvant treatment of breast cancer of known histology and detected on screening in a large cohort of patients treated by the surgeons of a health region. DESIGN: Part prospective, part retrospective observational study using the databases of a region''s breast screening programme and of the cancer registry. SETTING: The former South East Thames region. SUBJECTS: 600 women aged 49-79 who presented during 1991-2 with invasive breast cancer up to 20 mm in diameter that had been detected on screening. These patients were treated by 35 surgeons. MAIN OUTCOME MEASURES: Mastectomy rate by surgeon and the use of adjuvant treatment (radiotherapy, tamoxifen, and chemotherapy) were compared with risk factors, tumour grade, resection margins, and axillary node status. RESULTS: The mastectomy rate varied between nil and 80%, although the numbers at these extremes were small (0/13 v 8/10). Surgeons operating on more than 20 such cases had a lower mastectomy rate (15%) than surgeons treating fewer cases (23%), but this difference was confounded by variation in casemix. There were also wide variations in mastectomy rates and in axillary sampling rates that were independent of casemix or caseload. There was broad agreement on the use of adjuvant tamoxifen (94%), but few patients received chemotherapy (2.5%). 78 patients (19%) did not receive radiotherapy, including 51 out of 317 patients with unfavourable tumours, and 26 patients did not receive tamoxifen. Whether the patient received adjuvant treatment was more dependent on referral by the surgeon than the risk factors for local recurrence and was independent of caseload. CONCLUSION: Mastectomy rates for similar tumours vary widely by surgeon independently of casemix or caseload, but surgeons with a higher caseload tend to have a lower mastectomy rate. Omission of postoperative radiotherapy or tamoxifen after conservative treatment is not related to risk factors for local recurrence or caseload. Confidential feedback of treatment profiles to individual surgeons has been used, but when benefit has been established treatment should be guided by evidence based protocol.     

Principles of Rodent Surgery for the New Surgeon

For both scientific and animal welfare reasons, training in basic surgical concepts and techniques should be undertaken before ever seeking to perform surgery on a rodent. Students, post-doctoral scholars, and others interested in performing surgery on rodents as part of a research protocol may not have had formal surgical training as part of their required coursework. Surgery itself is a technical skill, and one that will improve with practice. The principles of aseptic technique, however, often remain unexplained or untaught. For most new surgeons, this vital information is presented in piecemeal fashion or learned on the job, neither of which is ideal. It may also make learning how to perform a particular surgery difficult, as the new surgeon is learning both a surgical technique and the principles of asepsis at the same time. This article summarizes and makes recommendations for basic surgical skills and techniques necessary for successful rodent surgery. This article is designed to supplement hands-on training by the user''s institution.     

The aetiologies of unilateral oculomotor nerve palsy: a clinical analysis on 121 patients

Background and purpose: To strengthen the understanding, increase the early diagnostic rate, and improve the outcome of unilateral oculomotor nerve palsy through the analysis of the 121 patients suffering from this disease in our hospital.

Methods: A retrospective study was performed on the 121 patients with unilateral oculomotor nerve palsy diagnosed at the Affiliated Hospital of Xuzhou Medical University from October 2014 to October 2015. The clinical data, such as gender, age, aetiology, clinical features, laboratory tests, and six months follow up reports were analyzed.

Results: The main causes identified in the 121 patients with unilateral oculomotor nerve palsy were intracranial aneurysm (29.8%), diabetic peripheral neuropathy (26.5%), painful ophthalmoplegia (9.9%), and other causes (33.9%). The results from the six month follow up showed that in all the patients, 53.7% were fully recovered, 38.0% improved, and 8.3% had no significant change in symptoms. The results also indicated that the patients with diabetic peripheral neuropathy had the best outcome with 71.9% full recovery rate, which was significantly higher than that in the patients with intracranial aneurysm (36.1%, p?<?.05), and idiopathic causes (44.5%, p?<?.05).

Conclusions: Our data indicates that intracranial aneurysm is the leading cause of unilateral oculomotor nerve palsy, and that diabetic peripheral neuropathy has better outcome. Understanding the common causes and clinical features of unilateral oculomotor nerve paralysis is helpful for its early diagnosis and treatment.     

Evaluating the accuracy and calibration of expert predictions under uncertainty: predicting the outcomes of ecological research

Aim Expert knowledge routinely informs ecological research and decision‐making. Its reliability is often questioned, but is rarely subject to empirical testing and validation. We investigate the ability of experts to make quantitative predictions of variables for which the answers are known. Location Global. Methods Experts in four ecological subfields were asked to make predictions about the outcomes of scientific studies, in the form of unpublished (in press) journal articles, based on information in the article introduction and methods sections. Estimates from students were elicited for one case study for comparison. For each variable, participants assessed a lower and upper bound, best guess and level of confidence that the observed value will lie within their ascribed interval. Responses were assessed for (1) accuracy: the degree to which predictions corresponded with observed experimental results, (2) informativeness: precision of the uncertainty bounds, and (3) calibration: degree to which the uncertainty bounds contained the truth as often as specified. Results Expert responses were found to be overconfident, specifying 80% confidence intervals that captured the truth only 49–65% of the time. In contrast, student 80% intervals captured the truth 76% of the time, displaying close to perfect calibration. Best estimates from experts were on average more accurate than those from students. The best students outperformed the worst experts. No consistent relationships were observed between performance and years of experience, publication record or self‐assessment of expertise. Main conclusions Experts possess valuable knowledge but may require training to communicate this knowledge accurately. Expert status is a poor guide to good performance. In the absence of training and information on past performance, simple averages of expert responses provide a robust counter to individual variation in performance.     

Learning new gait patterns is enhanced by specificity of training rather than progression of task difficulty

The use of motor learning strategies may enhance rehabilitation outcomes of individuals with neurological injuries (e.g., stroke or cerebral palsy). A common strategy to facilitate learning of challenging tasks is to use sequential progression – i.e., initially reduce task difficulty and slowly increase task difficulty until the desired difficulty level is reached. However, the evidence related to the use of such sequential progressions to improve learning is mixed for functional skill learning tasks, especially considering situations where practice duration is limited. Here, we studied the benefits of sequential progression using a functional motor learning task that has been previously used in gait rehabilitation. Three groups of participants (N = 43) learned a novel motor task during treadmill walking using different learning strategies. Participants in the specific group (n = 21) practiced only the criterion task (i.e., matching a target template that was scaled-up by 30%) throughout the training. Participants in the sequential group (n = 11) gradually progressed to the criterion task (from 3% to 30% in increments of 3%), whereas participants in the random group (n = 11) started at 3% and progressed in random increments (involving both increases and decreases in task difficulty) to the criterion task. At the end of training, kinematic tracking performance on the criterion task was evaluated in all participants both with and without visual feedback. Results indicated that the tracking error was significantly lower in the specific group, and no differences were observed between the sequential and the random progression groups. The findings indicate that the amount of practice in the criterion task is more critical than the difficulty and variations of task practice when learning new gait patterns during treadmill walking.     

Prolonged maturation of auditory perception and learning in gerbils

In humans, auditory perception reaches maturity over a broad age range, extending through adolescence. Despite this slow maturation, children are considered to be outstanding learners, suggesting that immature perceptual skills might actually be advantageous to improvement on an acoustic task as a result of training (perceptual learning). Previous non‐human studies have not employed an identical task when comparing perceptual performance of young and mature subjects, making it difficult to assess learning. Here, we used an identical procedure on juvenile and adult gerbils to examine the perception of amplitude modulation (AM), a stimulus feature that is an important component of most natural sounds. On average, Adult animals could detect smaller fluctuations in amplitude (i.e., smaller modulation depths) than Juveniles, indicating immature perceptual skills in Juveniles. However, the population variance was much greater for Juveniles, a few animals displaying adult‐like AM detection. To determine whether immature perceptual skills facilitated learning, we compared naïve performance on the AM detection task with the amount of improvement following additional training. The amount of improvement in Adults correlated with naïve performance: those with the poorest naïve performance improved the most. In contrast, the naïve performance of Juveniles did not predict the amount of learning. Those Juveniles with immature AM detection thresholds did not display greater learning than Adults. Furthermore, for several of the Juveniles with adult‐like thresholds, AM detection deteriorated with repeated testing. Thus, immature perceptual skills in young animals were not associated with greater learning. © 2010 Wiley Periodicals, Inc. Develop Neurobiol 70: 636–648, 2010     

Effects of suture material on incision healing, growth and survival of juvenile largemouth bass implanted with miniature radio transmitters: case study of a novice and experienced fish surgeon

Juvenile largemouth bass Micropterus salmoides , intraperitoneally implanted with microradio transmitters exhibited short-term (5 days) inflammation around the incision and suture insertion points for both non-absorbable braided silk and non-absorbable polypropylene monofilament, but in the longer term (20 days) almost all sutures were shed and the incisions were completely healed. Cumulative mortality was higher for fish with braided silk sutures, however, post-mortem analysis revealed that violations to the gastro-intestinal tract from the surgical procedure were the usual cause of the mortality. Mortality was generally low in control fish. The two surgeons who performed the implantations differed substantially in experience. Despite receiving basic training, the novice surgeon took longer to complete the surgeries, had reduced suture precision and experienced more fish mortality relative to the experienced surgeon. For both surgeons, it took longer to complete suturing with polypropylene than with braided silk. During the surgery day, the experienced surgeon exhibited consistently rapid surgery times, whereas the novice surgeon exhibited significantly improved speed as the number of surgeries completed increased. This study suggests that microtransmitters can be successfully implanted in juvenile largemouth bass but some mortality can be expected. This mortality seems to be independent of suture material, but dependent upon the experience of the surgeon.