Perioperative Pain Management for Thoracic Surgery: A Multi-Layered Approach.

Cardiothoracic surgeries frequently pose unique challenges in the management of perioperative acute pain that require a multifaceted and personalized approach in order to optimize patient outcomes. This article discusses various analgesic strategies including regional anesthesia techniques such as thoracic epidurals, erector spinae plane blocks, and serratus anterior plane blocks and underscores the significance of perioperative multimodal medications, while providing nuanced recommendations for their use. This article further attempts to provide evidence for the efficacy of the different modalities and compares the effectiveness of the choice of analgesia. The roles of Acute Pain Services (APS) and Transitional Pain Services (TPS) in mitigating opioid dependence and chronic postsurgical pain are also discussed. Precision medicine is also presented as a potential way to offer a patient tailored analgesic strategy. Supported by various randomized controlled trials and meta-analyses, the article concludes that an integrated, patient-specific approach encompassing regional anesthesia and multimodal medications, while also utilizing the services of the Acute Pain Service can help to enhance pain management outcomes in cardiothoracic surgery.

Sport-Specific AMCaMP: New Modular Tools for Measuring Adolescent Self-Confidence In Sport-Specific Movement.

Background: Despite increasing interest in psychological factors that affect the impact of self-efficacy on readiness to return to play, few clinical tools are available to assess self-confidence in performing sports-specific movement patterns in the pediatric/adolescent population. Hypothesis/Purpose: The purpose of this study was to test the psychometric properties of sports-specific modules to supplement a general measure of movement self-efficacy, the Adolescent Measure of Confidence and Movement Performance (AMCaMP). Study Design: Quasi-experimental cross-sectional validation. Methods: After preliminary testing for readability and ease of administration, one of 12 sport-specific modules pertinent to the individual's sport (baseball, softball, basketball, football, gymnastics, cheerleading, soccer, ballet, swimming, lacrosse, tennis, and cross country) were administered to 14,744 patients, 11-18 years of age, drawn from 12 pediatric sports physical therapy facilities in a single health care system. Respondents completed the assigned sport-specific self-report questionnaire at initial visit and conclusion of the episode of care. Results: Based on sample sizes, Bartlett's Test of Sphericity, and Kaiser-Myer-Olkin measures, nine modules (baseball, softball, basketball, football, gymnastics, cheerleading, soccer, ballet, and swimming) were deemed suitable for factor analysis. Each module sample was divided into test validation samples. Exploratory factor analysis revealed an underlying structure ranging from one to three factors depending upon the module. Subsequent confirmatory factor analyses fully supported the hypothesized factor structures for each module except swimming. Additional analyses to determine coefficient alpha (range=0.8-0.976), Standard Error of Measurement (range=1.12-2.33), and Minimum Detectable Change (range=3.1-6.47) confirmed the reliability of each of these modules. Conclusion: AMCAMP sport-specific modules are reliable and valid self-report tools to capture self-confidence in performing sport-specific movements to supplement AMCAMP's evaluation of self-efficacy in performing the general movements of everyday life. The results of this study support using these modules as part of the overall clinical evaluation of psychological readiness to return to sport. Level of Evidence: Level 3b.

Li and Atick's theory of efficient binocular coding: A tutorial and mini-review.

Li and Atick (Network: Computation in Neural Systems 5 (1994) 157-174) presented a theory of efficient binocular encoding that explains a number of experimental findings. A binocular neuron is conventionally described in terms of two channels: the left and right eyes. Li and Atick's theory instead describes the neuron in terms of two alternative channels: the binocular sum and difference. The advantage of the latter description is that, unlike the left and right eye channels, the summation and differencing channels are usually uncorrelated; this means that each channel can be optimised independently of the other. The theory shows how to derive optimal receptive fields for the binocular summation and differencing channels; from these, it is easy to derive the neuron's optimal left and right eye receptive fields. The functional reality of the summation and differencing channels is demonstrated by a series of adaptation studies that confirm some counterintuitive predictions of the theory. Here we provide an accessible account of the theory, and review the evidence supporting it.

Lineup identification in young and older witnesses: does describing the criminal help or hinder?

The world population is getting older and, as a result, the number of older victims of crime is expected to increase. It is therefore essential to understand how ageing affects eyewitness identification, so procedures can be developed that enable victims of crime of all ages to provide evidence as accurately and reliably as possible. In criminal investigations, witnesses often provide a description of the perpetrator of the crime before later making an identification. While describing the perpetrator prior to making a lineup identification can have a detrimental effect on identification in younger adults, referred to as verbal overshadowing, it is unclear whether older adults are affected in the same way. Our study compared lineup identification of a group of young adults and a group of older adults using the procedure that has consistently revealed verbal overshadowing in young adults. Participants watched a video of a mock crime. Following a 20-min filled delay, they either described the perpetrator or completed a control task. Immediately afterwards, they identified the perpetrator from a lineup, or indicated that the perpetrator was not present, and rated their confidence. We found that describing the perpetrator decreased subsequent correct identification of the perpetrator in both young and older adults. This effect of verbal overshadowing was not explained by a change in discrimination but was consistent with participants adopting a more conservative criterion. Confidence and response time were both found to predict identification accuracy for young and older groups, particularly in the control condition.

Regional anesthesia and the acute pain service: compliance and controversies.

PURPOSE OF REVIEW: The aims of this article are three-fold: first, to describe the necessary elements that result in accurate and compliant billing practice; second, to discuss billing in the context of new blocks and liposomal bupivacaine; and third, to gain a better understanding of compliance law. RECENT FINDINGS: Regional anesthesia techniques provide an appealing alternative to opioid medication for pain management. However, these techniques also increase the cost of care. As new peripheral and fascial plane blocks emerge, proper coding has become more complex. SUMMARY: Familiarity with documentation, billing, and compliance requirements can help maintain proper reimbursement rates, as well as limit potential downstream consequences. Most importantly this can help increase the viability and success of an acute pain service.

Stereoscopic depth adaptation from binocularly correlated versus anti-correlated noise: Test of an efficient coding theory of stereopsis.

Stereoscopic, or "3D" vision in humans is mediated by neurons sensitive to the disparities in the positions of objects in the two eyes' views. A disparity-sensitive neuron is typically characterized by its responses to left- and right-eye monocular signals, SL and SR, respectively. However, it can alternatively be characterized by sensitivity to the sum of the two eyes' inputs, S+ = SL + SR, and the difference, S- = SL - SR. Li and Atick's theory of efficient binocular encoding proposes that the S+ and S- signals can be separately weighted to maximize the efficiency with which binocular information is encoded. This adaptation changes each neuron's sensitivity and preferred binocular disparity, resulting in predicted effects on the perceived stereoscopic depth of objects. To test these predictions, we measured the apparent depth of a random-dot stereogram with an 'in-front' target following adaptation to binocularly correlated or anti-correlated horizontally-oriented grating stimuli, which reduce sensitivity to the S+ and S- signals, respectively, but which contain no conventional stereo-depth signals. The anti-correlated noise adaptation made the target appear relatively closer to the background than the correlated noise adaptation, with differences of up to 60%. We show how this finding can be accommodated by a standard model of binocular disparity processing, modified to incorporate the binocular adaptation suggested by Li and Atick's theory.

Face perception inherits low-level binocular adaptation.

In previous work (May & Zhaoping, 2016; May, Zhaoping, & Hibbard, 2012), we have provided evidence that the visual system efficiently encodes binocular information using separately adaptable binocular summation and differencing channels. In that work, binocular test stimuli delivered different grating patterns to the two binocular channels; selective adaptation of one of the binocular channels made participants more likely to see the other channel's grating pattern. In the current study, we extend this paradigm to face perception. Our test stimuli delivered different face images to the two binocular channels, and we found that selective adaptation of one binocular channel biased the observer to perceive the other channel's face image. We show that the perceived identity, gender, emotional expression, or direction of 3-D rotation of a facial test image can be influenced by pre-exposure to binocular random-noise patterns that contain no meaningful spatial structure. Our results provide compelling evidence that face-processing mechanisms can inherit adaptation from low-level sites. Our adaptation paradigm targets the low-level mechanisms in such a way that any response bias or inadvertent adaptation of high-level mechanisms selective for face categories would reduce, rather than produce, the measured effects of adaptation.

THE ADOLESCENT MEASURE OF CONFIDENCE AND MUSCULOSKELETAL PERFORMANCE (AMCAMP): DEVELOPMENT AND INITIAL VALIDATION.

BACKGROUND: Although the relationship of self-efficacy to sports performance is well established, little attention has been paid to self-efficacy in the movements or actions that are required to perform daily activities and prepare the individual to resume sports participation following an injury and associated period of rehabilitation. There are no instruments to measure self-confidence in movement validated in an adolescent population. PURPOSE: The purpose of this paper is to report on the development of the AMCaMP, a self-report measure of confidence in movement and provide some initial evidence to support its use as a measure of confidence in movement. METHODS: The AMCaMP was adapted from OPTIMAL, a self-report instrument that measures confidence in movement, which had been previously designed and validated in an adult population. Data were collected from 1,115 adolescent athletes from 12 outpatient physical therapy clinics in a single healthcare system. RESULTS: Exploratory factor analysis of the 22 items of the AMCaMP using a test sample revealed a three factor structure (trunk, lower body, upper body). Confirmatory factor analysis using a validation sample demonstrated a similar model fit with the data. Reliability of scores on each of three clusters of items identified by factor analysis was assessed with coefficient alpha (range = 0.82 to 0.94), Standard Error of Measurement (1.38 to 2.74), and Minimum Detectable Change (3.83 to 7.6). CONCLUSIONS: AMCaMP has acceptable psychometric properties for use in adolescents (ages 11 to 18) as a patient-centric outcome measure of confidence in movement abilities after rehabilitation. LEVEL OF EVIDENCE: IV.

Efficient Coding Theory Predicts a Tilt Aftereffect from Viewing Untilted Patterns.

The brain is bombarded with a continuous stream of sensory information, but biological limitations on the data-transmission rate require this information to be encoded very efficiently [1]. Li and Atick [2] proposed that the two eyes' signals are coded efficiently in the brain using mutually decorrelated binocular summation and differencing channels; when a channel is strongly stimulated by the visual input, such that sensory noise is negligible, the channel should undergo temporary desensitization (known as adaptation). To date, the evidence for this theory has been limited [3, 4], and the binocular differencing channel is missing from many models of binocular integration [5-10]. Li and Atick's theory makes the remarkable prediction that perceived direction of tilt (clockwise or counterclockwise) of a test pattern can be controlled by pre-exposing observers to visual adaptation patterns that are untilted or even have no orientation signal. Here, we confirm this prediction. Each test pattern consisted of different images presented to the two eyes such that the binocular summation and difference signals were tilted in opposite directions, to give ambiguous information about tilt; by selectively desensitizing one or other of the binocular channels using untilted or non-oriented binocular adaptation patterns, we controlled the perceived tilt of the test pattern. Our results provide compelling evidence that the brain contains binocular summation and differencing channels that adapt to the prevailing binocular statistics.

Inefficiency of orientation averaging: Evidence for hybrid serial/parallel temporal integration.

Intuition suggests that increased viewing time should allow for the accumulation of more visual information, but scant support for this idea has been found in studies of voluntary averaging, where observers are asked to make decisions based on perceived average size. In this paper we examine the dynamics of information accrual in an orientation-averaging task. With orientation (unlike intensive dimensions such as size), it is relatively safe to use an item's physical value as an approximation for its average perceived value. We displayed arrays containing eight iso-eccentric Gabor patterns, and asked six trained psychophysical observers to compare their average orientation with that of probe stimuli that were visible before, during, or only after the presentation of the Gabor array. From the relationship between orientation variance and human performance, we obtained estimates of effective set size, i.e., the number of items that an ideal observer would need to assess in order to estimate average orientation as well as our human observers did. We found that display duration had only a modest influence on effective set size. It rose from an average of ∼2 for 0.1-s displays to an average of ∼3 for 3.3-s displays. These results suggest that the visual computation is neither purely serial nor purely parallel. Computations of this nature can be made with a hybrid process that takes a series of subsamples of a few elements at a time.

Micheli Anterior Cruciate Ligament Reconstruction in Skeletally Immature Youths: A Retrospective Case Series With a Mean 3-Year Follow-up.

BACKGROUND: The management of anterior cruciate ligament (ACL) tears in the skeletally immature patient remains controversial. Outcomes on a physeal-sparing technique using the iliotibial band for combined intra-articular and extra-articular ACL reconstruction, called the Micheli technique, have been described and reported by the original authors. PURPOSE: To evaluate the clinical outcomes of a physeal-sparing technique using the iliotibial band for combined intra-articular and extra-articular ACL reconstruction. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 2005 and 2011, all patients who underwent Micheli ACL reconstruction performed by a single surgeon were identified. A minimum of 3 years' growth remaining was a prerequisite for Micheli reconstruction. Patients were excluded if postoperative follow-up was less than 1 year. Patients were evaluated for functional outcomes, satisfaction, graft survival, radiographic and clinical evidence of growth disturbance, and the need for additional procedures. RESULTS: Twenty-one patients (22 knees) met the inclusion criteria for this study. The mean age at the time of surgery was 11.8 years (range, 9.9-14.0 years). All patients were male. There were 4 concomitant meniscal repairs and 5 partial meniscectomies performed. All patients (100%) completed follow-up at a mean duration of 3.0 years (range, 1.0-6.9 years). Overall, 6 knees (27%) underwent reoperation. Of these, 3 knees (14%) underwent revision ACL surgery: 2 revision reconstructions at 2.8 and 4.0 years postoperatively and 1 graft shrinkage at 4.7 months postoperatively. Three knees (14%) underwent subsequent meniscal procedures, including 2 partial meniscectomies and 1 meniscal repair. Of the 19 knees that did not require revision ACL surgery, the median patient satisfaction score was 10 (range, 9-10). The mean Pediatric International Knee Documentation Committee score was 96.5 ± 2.9, and the mean Lysholm score was 95.0 ± 6.1. The median preinjury Tegner activity level was 8 (range, 6-10), and the median postoperative Tegner activity level was 8 (range, 6-10). Of the 19 knees that did not require revision ACL surgery, all had a normal Lachman test result, with a firm endpoint and normal pivot shift. At follow-up, 53% of knees had closed physes. There were no angular deformities or limb-length discrepancies. CONCLUSION: At a mean 3-year follow-up, the study findings confirmed excellent functional outcomes, a low ACL revision rate, and no growth disturbances. Patients returned to their preoperative activity level after reconstruction. This procedure offers a safe and effective ACL reconstruction option in children with several years of growth remaining.

Connecting psychophysical performance to neuronal response properties I: Discrimination of suprathreshold stimuli.

One of the major goals of sensory neuroscience is to understand how an organism's perceptual abilities relate to the underlying physiology. To this end, we derived equations to estimate the best possible psychophysical discrimination performance, given the properties of the neurons carrying the sensory code.We set up a generic sensory coding model with neurons characterized by their tuning function to the stimulus and the random process that generates spikes. The tuning function was a Gaussian function or a sigmoid (Naka-Rushton) function.Spikes were generated using Poisson spiking processes whose rates were modulated by a multiplicative, gamma-distributed gain signal that was shared between neurons. This doubly stochastic process generates realistic levels of neuronal variability and a realistic correlation structure within the population. Using Fisher information as a close approximation of the model's decoding precision, we derived equations to predict the model's discrimination performance from the neuronal parameters. We then verified the accuracy of our equations using Monte Carlo simulations. Our work has two major benefits. Firstly, we can quickly calculate the performance of physiologically plausible population-coding models by evaluating simple equations, which makes it easy to fit the model to psychophysical data. Secondly, the equations revealed some remarkably straightforward relationships between psychophysical discrimination performance and the parameters of the neuronal population, giving deep insights into the relationships between an organism's perceptual abilities and the properties of the neurons on which those abilities depend.

Connecting psychophysical performance to neuronal response properties II: Contrast decoding and detection.

The purpose of this article is to provide mathematical insights into the results of some Monte Carlo simulations published by Tolhurst and colleagues (Clatworthy, Chirimuuta, Lauritzen, & Tolhurst, 2003; Chirimuuta & Tolhurst, 2005a). In these simulations, the contrast of a visual stimulus was encoded by a model spiking neuron or a set of such neurons. The mean spike count of each neuron was given by a sigmoidal function of contrast, the Naka-Rushton function. The actual number of spikes generated on each trial was determined by a doubly stochastic Poisson process. The spike counts were decoded using a Bayesian decoder to give an estimate of the stimulus contrast. Tolhurst and colleagues used the estimated contrast values to assess the model's performance in a number of ways, and they uncovered several relationships between properties of the neurons and characteristics of performance. Although this work made a substantial contribution to our understanding of the links between physiology and perceptual performance, the Monte Carlo simulations provided little insight into why the obtained patterns of results arose or how general they are. We overcame these problems by deriving equations that predict the model's performance. We derived an approximation of the model's decoding precision using Fisher information. We also analyzed the model's contrast detection performance and discovered a previously unknown theoretical connection between the Naka-Rushton contrast-response function and the Weibull psychometric function. Our equations give many insights into the theoretical relationships between physiology and perceptual performance reported by Tolhurst and colleagues, explaining how they arise and how they generalize across the neuronal parameter space.

One "shape" fits all: the orientation bandwidth of contour integration.

The ability of human participants to integrate fragmented stimulus elements into perceived coherent contours (amidst a field of distracter elements) has been intensively studied across a large number of contour element parameters, ranging from luminance contrast and chromaticity to motion and stereo. The evidence suggests that contour integration performance depends on the low-level Fourier properties of the stimuli. Thus, to understand contour integration, it would be advantageous to understand the properties of the low-level filters that the visual system uses to process contour stimuli. We addressed this issue by examining the role of stimulus element orientation bandwidth in contour integration, a previously unexplored area. We carried out three psychophysical experiments, and then simulated all of the experiments using a recently developed two-stage filter-overlap model whereby the contour grouping occurs by virtue of the overlap between the filter responses to different elements. The first stage of the model responds to the elements, while the second stage integrates the responses along the contour. We found that the first stage had to be fairly broadly tuned for orientation to account for our results. The model showed a very good fit to a large data set with relatively few free parameters, suggesting that this class of model may have an important role to play in helping us to better understand the mechanisms of contour integration.

Contour extracting networks in early extrastriate cortex.

Neurons in the visual cortex process a local region of visual space, but in order to adequately analyze natural images, neurons need to interact. The notion of an ''association field'' proposes that neurons interact to extract extended contours. Here, we identify the site and properties of contour integration mechanisms. We used functional magnetic resonance imaging (fMRI) and population receptive field (pRF) analyses. We devised pRF mapping stimuli consisting of contours. We isolated the contribution of contour integration mechanisms to the pRF by manipulating the contour content. This stimulus manipulation led to systematic changes in pRF size. Whereas a bank of Gabor filters quantitatively explains pRF size changes in V1, only V2/V3 pRF sizes match the predictions of the association field. pRF size changes in later visual field maps, hV4, LO-1, and LO-2 do not follow either prediction and are probably driven by distinct classical receptive field properties or other extraclassical integration mechanisms. These pRF changes do not follow conventional fMRI signal strength measures. Therefore, analyses of pRF changes provide a novel computational neuroimaging approach to investigating neural interactions. We interpreted these results as evidence for neural interactions along cooriented, cocircular receptive fields in the early extrastriate visual cortex (V2/V3), consistent with the notion of a contour association field.