Pediatric Endoscopy Blocks: Enhanced Efficiency and Endoscopist Satisfaction.

OBJECTIVES: Endoscopic procedures are increasingly performed for children and adolescents and these interventions represent a central element of both pediatric gastroenterology (GI) care and revenues. It remains unclear, however, which scheduling paradigm maximizes efficiency of resource utilization and delivery of care in this arena. In this study, we evaluate the impact of shifting from shared endoscopy blocks to individual, provider-specific endoscopy blocks for scheduling endoscopic procedures in our tertiary care academic center. METHODS: The implemented endoscopy block system involves a single endoscopist performing procedures in an allocated room for the entire half-day period of time, with most providers having 1-3.5 day blocks per month. We analyzed block fragmentation (multiple providers in a single block), block utilization, and procedure volume, comparing the 8-month period prior to implementation of the block system (pre-implementation period) with the 8-month period following implementation of the block system (post-implementation period). Provider satisfaction and perceptions were assessed by survey pre- and post-implementation. Standard descriptive statistics were utilized for analysis. RESULTS: In the pre- and post-implementation periods, 22 half-day blocks were allocated to pediatric GI. In the pre-implementation period, mean utilization of these blocks was 65.9% (range: 47%-77%). In the post-implementation period, mean % utilization was 79.8% (range: 64%-89%). Overall endoscopy procedure volume increased from 279 in the pre-implementation period to 419 in the post-implementation period. Provider perception of endoscopy efficiency was enhanced by the block system, with 68.4% of pediatric GI respondents rating endoscopy as "efficient" post-implementation (vs 19% pre-implementation) and 63.2% indicating that the block system directly enhanced efficiency. A total of 63.2% reported increased personal procedure volume and 84.2% reported perceived increase in overall procedure volume with block system implementation. CONCLUSIONS: Strategic approaches for scheduling endoscopic procedures carry the potential to enhance efficiency and experience for both providers and patients. Implementation of the endoscopy block system was associated with increased procedure volumes and block utilization as well as a more positive experience for the majority of providers. Schedule adjustments with analysis of associated efficiency and satisfaction metrics can optimize pediatric endoscopy practice.

A case-control study of visual, auditory and audio-visual sensory interactions in children with autism spectrum disorder.

To assess the relative integrity of early visual and auditory processes in autism spectrum disorder (ASD), we used frequency-tagged visual and auditory stimulation and high-density electroencephalogram recordings of unimodal and dual-modality responses in a case-control design. To test for the specificity of effects on ASD, we recorded from a smaller group of children with attention-deficit hyperactivity disorder (ADHD). Horizontal 3 cycle per degree (cpd) gratings were presented at 5 Hz, and a random stream of /ba/, /da/, /ga/ syllables was presented at 6 Hz. Grating contrast response functions were measured unimodally and in the presence of a 64-dB auditory input. Auditory response functions were measured unimodally and in the presence of a 40% contrast grating. Children with ASD (n = 34) and ADHD (n = 13) showed a common lack of audio-visual interaction compared to typically developing children (n = 40) when measured at the first harmonic of the visual stimulus frequency. Both patient groups also showed depressed first harmonic responses at low contrast, but the ADHD group had consistently higher first-harmonic responses at high contrast. Children with ASD had a preferential loss of second-harmonic (transient) responses. The alteredtransient responses in ASD are likely to arise very early in the visual pathway and could thus have downstream consequences for many other visual mechanisms and processes. The alteration in audio-visual interaction could be a signature of a comorbid phenotype shared by ASD and ADHD, possibly due to alterations in attentional selection systems.

Autism sensory dysfunction in an evolutionarily conserved system.

There is increasing evidence for a strong genetic basis for autism, with many genetic models being developed in an attempt to replicate autistic symptoms in animals. However, current animal behaviour paradigms rarely match the social and cognitive behaviours exhibited by autistic individuals. Here, we instead assay another functional domain-sensory processing-known to be affected in autism to test a novel genetic autism model in Drosophila melanogaster. We show similar visual response alterations and a similar development trajectory in Nhe3 mutant flies (total n = 72) and in autistic human participants (total n = 154). We report a dissociation between first- and second-order electrophysiological visual responses to steady-state stimulation in adult mutant fruit flies that is strikingly similar to the response pattern in human adults with ASD as well as that of a large sample of neurotypical individuals with high numbers of autistic traits. We explain this as a genetically driven, selective signalling alteration in transient visual dynamics. In contrast to adults, autistic children show a decrease in the first-order response that is matched by the fruit fly model, suggesting that a compensatory change in processing occurs during development. Our results provide the first animal model of autism comprising a differential developmental phenotype in visual processing.

Evidence for long-range spatiotemporal interactions in infant and adult visual cortex.

The development of spatiotemporal interactions giving rise to classical receptive field properties has been well studied in animal models, but little is known about the development of putative nonclassical mechanisms in any species. Here we used visual evoked potentials to study the developmental status of spatiotemporal interactions for stimuli that were biased to engage long-range spatiotemporal integration mechanisms. We compared responses to widely spaced stimuli presented either in temporal succession or at the same time. The former configuration elicits a percept of apparent motion in adults but the latter does not. Component flash responses were summed to make a linear prediction (no spatiotemporal interaction) for comparison with the measured evoked responses to sequential or simultaneous flash conditions. In adults, linear summation of the separate flash responses measured with 40% contrast stimuli predicted sequential flash responses twice as large as those measured, indicating that the response measured under apparent motion conditions is subadditive. Simultaneous-flash responses at the same spatial separation were also subadditive, but substantially less so. The subadditivity in both cases could be modeled as a simple multiplicative gain term across all electrodes and time points. In infants aged 3-8 months, responses to the stimuli used in adults were similar to their linear predictions at 40%, but the responses measured at 80% contrast resembled the subadditive responses of the adults for both sequential and simultaneous flash conditions. We interpret the developmental data as indicating that adult-like long-range spatiotemporal interactions can be demonstrated by 3-8 months, once stimulus contrast is high enough.

Electrophysiological measures of low-level vision reveal spatial processing deficits and hemispheric asymmetry in autism spectrum disorder.

There is accumulating evidence from electrophysiological studies that low-level visual processing is atypical in individuals with autism spectrum disorders (ASDs). Abnormalities in early stages of sensory processing are of interest because they could lead to downstream functional deficits in social or cognitive domains. Using steady-state visual evoked potentials (SSVEPs), we studied how well spatial information is transmitted over a wide range of spatial frequencies (2-30 cycles/deg), including those at the limit of visibility (visual acuity). SSVEPs were recorded over 128 channels in 16 ASD participants between 5 and 17 years old and 17 age-matched, neurotypical (NT) participants. We observed a selective reduction of the amplitude of the SSVEP second harmonic pattern reversal response between 5 and 17 cycles/deg. Responses measured at the fourth harmonic were normal at all spatial frequencies tested, as were responses at the lowest and highest spatial frequencies at the second harmonic. The reduction of second harmonic responses occurred preferentially over right occipital electrodes. Because response abnormalities are restricted to a specific response harmonic and to specific ranges of spatial frequency, we can rule out nonspecific differences between the ASD participants and the NT controls. This particular pattern of loss, combined with the observed exaggeration of the loss over the right hemisphere, suggests that a highly specific neural substrate early in the visual pathway is compromised in ASD.

The design and evaluation of a novel algorithm for automated preference card optimization.

BACKGROUND: Inaccurate surgical preference cards (supply lists) are associated with higher direct costs, waste, and delays. Numerous preference card improvement projects have relied on institution-specific, manual approaches of limited reproducibility. We developed and tested an algorithm to facilitate the first automated, informatics-based, fully reproducible approach. METHODS: The algorithm cross-references the supplies used in each procedure and listed on each preference card and uses a time-series regression to estimate the likelihood that each quantity listed on the preference card is inaccurate. Algorithm performance was evaluated by measuring changes in direct costs between preference cards revised with the algorithm and preference cards that were not revised or revised without use of the algorithm. Results were evaluated with a difference-in-differences (DID) multivariate fixed-effects model of costs during an 8-month pre-intervention and a 15-month post-intervention period. RESULTS: The accuracies of the quantities of 469 155 surgeon-procedure-specific items were estimated. Nurses used these estimates to revise 309 preference cards across eight surgical services corresponding to, respectively, 1777 and 3106 procedures in the pre- and post-intervention periods. The average direct cost of supplies per case decreased by 8.38% ($352, SD $6622) for the intervention group and increased by 13.21% ($405, SD $14 706) for the control group (P < .001). The DID analysis showed significant cost reductions only in the intervention group during the intervention period (P < .001). CONCLUSION: The optimization of preference cards with a variety of institution-specific, manually intensive approaches has led to cost savings. The automated algorithm presented here produced similar results that may be more readily reproducible.

Cross-modal extinction in a boy with severely autistic behaviour and high verbal intelligence.

Anecdotal reports from individuals with autism suggest a loss of awareness to stimuli from one modality in the presence of stimuli from another. Here we document such a case in a detailed study of A.M., a 13-year-old boy with autism in whom significant autistic behaviours are combined with an uneven IQ profile of superior verbal and low performance abilities. Although A.M.'s speech is often unintelligible, and his behaviour is dominated by motor stereotypies and impulsivity, he can communicate by typing or pointing independently within a letter board. A series of experiments using simple and highly salient visual, auditory, and tactile stimuli demonstrated a hierarchy of cross-modal extinction, in which auditory information extinguished other modalities at various levels of processing. A.M. also showed deficits in shifting and sustaining attention. These results provide evidence for monochannel perception in autism and suggest a general pattern of winner-takes-all processing in which a stronger stimulus-driven representation dominates behaviour, extinguishing weaker representations.

Sensitivity and configuration-specificity of orientation-defined texture processing in infants and adults.

Here we use textures made up of widely spaced Gabor patches to compare infant and adult sensitivity to the global organization of the elements comprising the textures. Visual Evoked Potentials (VEPs) were recorded to alterations between random images and images containing varying proportions of patches that were of the same orientation. The patches were placed on rectangular, hexagonal or random lattices. Texture-specific responses were robust in adults and their VEP threshold was reached when 1-17% of the patches had the same orientation in the structured image. Infant thresholds were approximately 20-60%. While infants are capable of detecting the global structure of our textures, their sensitivity is low. In adults we found, unexpectedly, that sensitivity and response gain were higher for horizontal compared to vertical global orientations. Infant sensitivity was the same for the two orientations. Comparable orientation anisotropies have not been previously reported for gratings, suggesting that the Gabor-defined textures are tapping different mechanisms. There were small, but measurable effects of the lattice type in adults, with the rectangular lattice producing the largest responses.

Development of contrast normalization mechanisms during childhood and adolescence.

Contrast sensitivity is regulated by neural mechanisms that flexibly adjust responsiveness to optimize stimulus encoding across different environments. Here we studied the developmental status of gain control mechanisms in school-age children (5-17years) and adults using a visual masking paradigm. A variable contrast, spatially random 2-D noise test pattern was masked by the presence of a superimposed independent noise pattern presented at 0, 12 and 40% contrast. Frequency-tagged steady state visual evoked potentials were used to separately record responses to the test (5.14Hz) and the mask (7.2Hz). By incrementally increasing the test contrast we measured contrast response functions for each mask contrast. The unmasked contrast response functions were largely similar in shape across age, but peak amplitude was higher in the children. Masking shifted the contrast response function rightward on the contrast axis in both the adults and older children, elevating contrast thresholds by a similar factor across age. However, in younger children, masking resulted in a change in the slope of the contrast response function. These findings suggest that immaturity in the contrast normalization process persists until approximately 11years of age.

Event-related potentials show configural specificity of global form processing.

Glass patterns are a type of moiré created when a random-dot field is overlaid with a rotated, translated or dilated copy. The overall form of the moiré cannot be detected using local processing mechanisms, and because of this, Glass patterns are useful probes of global form processing. Here, we use event-related potentials to show that certain global organizations (concentric structure created by rotation and radial structure produced by dilation) produce much larger brain responses than others (linear structure created by translation). The results are consistent with the existence of specialized form processing mechanisms in the extrastriate cortex.

Attentional skills during the first 6 months of age in autism spectrum disorder.

OBJECTIVE: To study the quality of early attention in autism spectrum disorder (ASD) through home movies. METHOD: Fifteen home movies from the first 6 months of life of children who later received a diagnosis of ASD were compared with home movies of 15 normal children. The diagnosis was performed after the third year of life of children by two senior child and adolescent psychiatrists using a checklist of symptoms according to the. The films of the two groups were mixed and rated by blind observers through a Grid for the Assessment of Attentional Skills in Infants, composed of 13 items grouped into three developmental areas. RESULTS: Using multivariate analysis of variance, the authors found significant differences between the two groups for the items in the social attention and the social behavior areas; on the contrary, there were no differences in nonsocial attention. CONCLUSIONS: The authors pose some hypotheses about a specific early-appearing impairment of attention in ASD in which children shift their spontaneous attention mainly toward nonsocial stimuli rather than toward social stimuli. The importance of this finding for early diagnosis and treatment is underlined.

Neural correlates of object-based attention.

Much research has been directed toward disentangling the "units" of attention: Is attention directed to locations in space, visual objects, or to individual features of an object? Moreover, there is considerable interest in whether attention increases the gain of neural mechanisms (signal enhancement) or acts by other means, such as reducing noise or narrowing channel tuning. To address these questions, we used a direct measure of signal strength: the amplitude of visual evoked potentials and a task in which selection could be based on a depth order cue but not on location. Attended and nonattended stimuli were presented at different temporal frequencies, and, thus, responses to the two stimuli could be analyzed separately even though they were presented simultaneously. Attention increased the amplitude of the second harmonic component of the response, but not the fourth harmonic. In addition, responses measured at the second harmonic, but not at the fourth harmonic, were larger for stimuli seen as behind. The results are consistent with the fourth harmonic being generated at a stage of processing that is not accessible to attention and where depth order has not been extracted. The second harmonic, on the other hand, is modifiable by attention and shows evidence for differential encoding of depth order.

Neural correlates of texture and contour integration in children with autism spectrum disorders.

In this study, we have used an electrophysiological paradigm to investigate the neural correlates of the visual integration of local signals across space to generate global percepts in a group of low functioning autistic kids. We have analyzed the amplitude of key harmonics of the Visual Evoked Potentials (VEPs) recorded while participants observed orientation-based texture and contour stimuli, forming coherent global patterns, alternating with visual patterns in which the same number of local elements were randomly oriented in order to loose any globally organized feature. Comparing the results of the clinical sample with those obtained in an age-matched control group, we have observed that in the texture conditions the 1st and 3rd harmonics, containing signature of global form processing (Norcia, Pei, Bonneh, Hou, Sampath, & Pettet, 2005), were present in the control group, while in the experimental group only the 1st harmonic was present. In the Contour condition the 1st harmonic was not present for both groups while the 3rd harmonic was significantly present in the control group but absent in the group with autism. Moreover, the amount of organization required to elicit significant 1st harmonic response in the texture condition was higher in the clinical group. The present results bring additional support to the idea that texture and contour processing are supported by independent mechanisms in normal vision. Autistic vision would thus be characterized by a preserved, perhaps weaker texture mechanism, possibly mediated by feedback interactions between visual areas, and by a disfunction of the mechanism supporting contour processing, possibly mediated by long-range intra-cortical connections. Within this framework, the residual ability to detect contours shown in psychophysical studies could be due to the contribution of the texture mechanism to contour processing.

Search superiority in autism within, but not outside the crowding regime.

Visual cognition of observers with autism spectrum disorder (ASD) seems to show an unbalance between the complementary functions of integration and segregation. This study uses visual search and crowding paradigms to probe the relative ability of children with autism, compared to normal developments children, to extract individual targets from cluttered backgrounds both within and outside the crowding regime. The data show that standard search follows the same pattern in the ASD and control groups with a strong effect of the set size that is substantially weakened by cueing the target location with a synchronous spatial cue. On the other hand, the crowding effect of eight flankers surrounding a small peripheral target is virtually absent in the clinical sample, indicating a superior ability to segregate cluttered visual items. This data, along with evidence of an impairment to the neural system for binding contours in ASD, bring additional support to the general idea of a shift of the trade-off between integration and segregation toward the latter. More specifically, they show that when discriminability is balanced across conditions, an advantage in odd-man out tasks is evident in ASD observers only within the crowding regime, when binding mechanism might get compulsorily triggered in normal observers.

Development of sensitivity to texture and contour information in the human infant.

Texture discrimination and bounding contour extraction are essential parts of the object segmentation and shape discrimination process. As such, successful texture and contour processing are key components underlying the development of the perception of both objects and surfaces. By recording visual-evoked potentials, we investigate whether young infants can detect orientation-defined textures and contours. We measured responses to an organized texture comprised of many Gabor patches of the same orientation, alternated with images containing the same number of patches, but all of random orientation. These responses were compared with a control condition consisting of the alternation between two independently random configurations. Significant difference potentials were found as early as 2-5 months, as were significant odd harmonics in the test conditions. Responses were also measured to Gabor patches organized either as circles (all patches tangent to an imaginary circular path) alternated with pinwheels (all patches having a fixed orientation offset from the path). Infants between 6 and 13 months also showed sensitivity to the global organization of the elements along contours. Differential responses to our texture and contour stimuli and their controls could only have been generated by mechanisms that are capable of comparing the relative orientation of 2 or more patches, as no local information at a single patch distinguished the random and organized textures or the circle and pinwheel configurations.