The effects of depth separation on lightness contrast and lightness assimilation

An intriguing paradox is created by the phenomena of lightness contrast, in which the difference in lightness between targets and inducers is over-estimated, and assimilation, in which this difference is under-estimated. Inducers’ spatial frequency is an important factor: inducers with low-spatial frequency seem to induce contrast whilst inducers with highspatial frequency seem to induce assimilation. The interaction of this factor with depth is less clear. Wolff (1934) found that contrast disappears when low-spatial frequency inducers are non-coplanar with targets, while Soranzo at al. (2010) found that contrast persists even with high-spatial frequency inducers when they are non-coplanar with the targets. The difference between these two studies is that Wolff manipulated actual depth, whilst Soranzo et al. manipulated stereoscopic depth. This study manipulated the actual distance between target and inducers, as well as Inducers’ Spatial frequency and Intensity. Participants indicated the target lightness by choosing the correspondent chip in a Munsell scale. Results suggest that high spatial-frequency inducers generate assimilation effects only when they are coplanar with the targets, but contrast effects when they are non-coplanar. Low-spatial frequency inducers generate contrast effects both when they are coplanar and at distance. We conclude that assimilation is more affected by distance than contrast

Behavioural and electrophysiological correlates of lightness contrast and assimilation

Lightness contrast and lightness assimilation are examples of the perception of a surface being influenced by surrounding areas. In contrast, a grey target is perceived lighter when neighbouring a dark surface, and darker when neighbouring a light surface. The reverse is true for assimilation. The general aims of this thesis were to investigate contrast and assimilation in parallel, using behavioural and electrophysiological methods to examine the responses. The first part of the project used a matching-chart method to assess the effect of depth separation on the perception of stimuli shown to elicit either contrast or assimilation, making a direct comparison between the effect on contrast and on assimilation. The second part of the project developed a forced-choice (lighter/darker) task to investigate the electrophysiological (ERP) responses associated with contrast and assimilation, thus investigating the time course of the associated neural processing, and whether contrast and assimilation result from different underlying processing. Throughout the studies, contrast effects were stronger with white inducers, whereas assimilation effects were stronger with black inducers. Both contrast and assimilation effects were disrupted when the target and inducer were separated by depth. When comparing contrast and assimilation responses, there was a difference in N1 amplitude in the left occipital area, but this was only apparent in one condition. Within other conditions, the P1 amplitude decreased as the strength of contrast effects increased and increased as the strength of assimilation increased. When comparing between conditions, a stronger contrast effect (white inducers) resulted in smaller amplitude than a weaker contrast effect (black inducers). The observation that both effects change after depth separation despite the 2D retinal image remaining equivalent, and the ERP activity throughout occipital and parietal areas suggest that contrast and assimilation require processing at the cortical level, rather than retinal processing alone

PSS32 Impact of dry eye on everyday life (Ideel) - Symptom bother: Estimating cut-off scores for dry eye severity groups

The aims of the study were to estimate score ranges associated with dry eye severity based on the Impact of Dry Eye on Everyday Life (IDEEL) Symptom Bother (SB) domain, and to evaluate the overall performance of the SB domain

Behavioural and Electrophysiological Correlates of Lightness Contrast and Assimilation

Lightness contrast and assimilation are opposite phenomena: in contrast grey targets appear darker when bordering bright rather than dark surfaces; in assimilation grey targets appear lighter when bordering bright rather than dark surfaces. The underlying neurophysiological mechanisms of these phenomena are not known. The aim of this study was to investigate the relationship between contrast and assimilation, and the timing and levels of perceptual and cognitive processing using combined behavioural and electrophysiological methods. Thirty undergraduate students (23 female, age range 18-48 years old) participated in a forced-choice (grey target is lighter/darker than a comparison square) task, using stimuli designed such that the inducers were in two configurations (small and large) and two shades (white and black). The behavioural data (more consistent and faster responses) corroborated previous findings of stronger contrast effects with white inducers and stronger assimilation effects with black inducers. According to the Event Related Potentials (ERP) results the mean amplitude was larger in conditions with less consistent and slower behavioural responses. Thus, with contrast responses P1 amplitude was larger with black than white inducers, and N1 amplitude was larger to assimilation than contrast when the configuration of the stimulus was held constant. These results suggest contrast may occur as early as P1 (~110 ms) and assimilation may occur later in N2 (~220 ms), whereas in some conditions, differences in ERPs associated with contrast versus assimilation may happen as early as in N1 (~170m), in occipital and parietal cortical sites

Psychosocial and productivity impact of caring for a child with peanut allergy

Background Limited previous research has assessed the psychosocial burden and productivity impact of caring for a child with peanut allergy and factors associated with burden. The objective of this research was to explore caregiver burden in terms of psychosocial and productivity impact of caring for a child with peanut allergy, the influence of caregiver and child gender on caregiver burden, and factors predicting caregiver burden in peanut allergy. Methods A cross-sectional survey of caregivers of children with peanut allergy was conducted in the United Kingdom, and included sociodemographic and clinical questions, EQ-5D, Hospital Anxiety and Depression Scale, Food Allergy Quality of Life-Parental Burden, Food Allergy Independent Measure, and productivity questions. Results One hundred caregivers (55% female) of children with peanut allergy (aged 4–15 years) completed the survey. Male and female caregivers reported mean levels of anxiety significantly higher than United Kingdom population norms. Caregivers of children with severe peanut allergy reported significant impacts on their careers and health-related quality of life. Neither caregiver nor child gender impacted burden, indicating that male and female caregivers are equally anxious and suffer the same level of negative career, productivity, and health-related quality-of-life impact due to their child’s peanut allergy. Caregivers’ perceived risk of outcomes related to their child’s peanut allergy (e.g., death or severe reaction) as measured by the Food Allergy Independent Measure independently predicted burden. Conclusions Caregivers of children with peanut allergy in the United Kingdom experience health-related quality-of-life, psychosocial, and productivity burden; this study demonstrates the high levels of anxiety reported by both male and female caregivers

Mapping the EQ-5D index from the cystic fibrosis questionnaire-revised using multiple modelling approaches.

BACKGROUND: This study was designed to develop a mapping algorithm to estimate EQ-5D utility values from Cystic Fibrosis Questionnaire-Revised (CFQ-R) data. METHODS: A cross-sectional survey of adults with cystic fibrosis (CF) was conducted in the UK. The survey consisted of the CFQ-R, the EQ-5D and a background questionnaire. Eight regression models, exploring item and domain level predictors, were evaluated using three different modelling approaches: ordinary least squares (OLS), Tobit, and a two-part model (TPM). Predictive performance in each model was assessed by intraclass correlations, information criteria (Bayesian information criteria and Alkaike information criteria), and root mean square error (RMSE). RESULTS: The survey was completed by 401 participants. For all modelling approaches the best performing item level model included all items, and the best performing domain level model included the CFQ-R Physical-, Role- and Emotional-functioning, Vitality, Eating Disturbances, Weight, and Digestive Symptoms domains and a selection of squared terms. Overall, the item level TPM, including age and gender covariates performed best within sample validation, but OLS and TPM domain models with squared terms performed best out-of-sample and are recommended for mapping purposes. CONCLUSIONS: Domain and item level models using all three modelling approaches reached an acceptable degree of predictive performance with domain models performing well in out-of-sample validation. These mapping functions can be applied to CFQ-R datasets to estimate EQ-5D utility values for economic evaluations of interventions for patients with cystic fibrosis. Further research evaluating model performance in an independent sample is encouraged

Burden of allergic rhinitis and impact of MP-AzeFlu from the patient perspective : pan European patient survey

Funding for this research was provided by Mylan Inc. Acknowledgements We thank Dr Ruth B Murray (Medscript NZ Ltd) for assistance in drafting and editing this manuscript.Peer reviewedPublisher PD

Peanut Allergy impact on PRoductivity and QUAlity of life (PAPRIQUA):Caregiver-reported psychosocial impact of peanut allergy on children

BACKGROUND: Limited research has examined the impact of peanut allergy (PA) on children using validated instruments to assess psychosocial burden and the factors influencing burden. OBJECTIVE: The PAPRIQUA study aimed to assess the caregiver-reported impact of living with PA on children's health-related quality of life (HRQL), correlations between PA severity and child's sex, and associations of caregivers' sex and anxiety with the proxy report of their child's HRQL and to identify significant predictors of a child's HRQL. METHODS: A cross-sectional survey of caregivers of children with mild, moderate and severe PA, based on caregiver perception, was conducted in the United Kingdom. Participants were recruited through a survey recruitment panel; a maximum quota of 20% who rated their child's PA as mild was set to ensure population diversity; however, the quota was not required as few participants considered their child's PA mild. The survey, funded by Aimmune Therapeutics, included sociodemographic and clinical questions, the EQ-5D-Y, Hospital Anxiety and Depression Scale, Food Allergy Quality of Life Questionnaire-Parent Form (FAQLQ-PF) and Food Allergy Independent Measure (FAIM). RESULTS: One hundred caregivers of children with PA (aged 4-15 years) completed the survey. Child's sex was not associated with proxy-reported burden. For younger children (aged 4-10 years), there was no effect of PA severity; parents of older children (aged 11-15 years) reported low to higher burden for their child on the EQ-5D-Y and FAQLQ-PF dependent upon PA severity. For all measures of child burden except the EQ-5D-Y, two or more reactions in the past 12 months and parental anxiety significantly predicted higher levels of burden for the child (P < .05-P < .001). Experiencing a life-threatening event in the past 12 months significantly predicted EQ-5D-Y proxy utility (P < .01). CONCLUSIONS AND CLINICAL RELEVANCE: Caregivers report that children with PA experience high levels of psychosocial burden, particularly those with more severe PA and a reaction history. Interventions to decrease caregiver anxiety and reaction frequency may help reduce the child's burden. Self-report studies in children with PA would help confirm these findings

The hidden burden of adult allergic rhinitis : UK healthcare resource utilisation survey

Funding Funding for this survey was provided by Meda Pharma.Peer reviewedPublisher PD

Allergy to Peanuts imPacting Emotions And Life (APPEAL): The impact of peanut allergy on children, teenagers, adults and caregivers in the UK and Ireland

The Allergy to Peanuts imPacting Emotions And Life study (APPEAL) explored the psychosocial burden of living with self-reported peanut allergy experienced by children, teenagers, adults and caregivers in the UK and Ireland. A two-stage (quantitative survey and qualitative interview [APPEAL-1]), cross-sectional study of the psychosocial burden of peanut allergy (APPEAL-2) was conducted. Quantitative data were evaluated using descriptive statistics and qualitative data were analysed using MAXQDA software. A conceptual model specific to UK and Ireland was developed using the concepts identified during the analysis. A total of 284 adults in the UK and Ireland completed the APPEAL-1 survey and 42 individuals participated in APPEAL-2. Respondents reported that peanut allergy restricts their choices in various situations, especially with regard to choosing food when eating out (87% moderately or severely restricted), choosing where to eat (82%), special occasions (76%) and when buying food from a shop (71%). Fifty-two percent of survey participants and 40% of interview participants reported being bullied because of PA. Psychological impact of peanut allergy included feeling at least moderate levels of frustration (70%), uncertainty (79%), and stress (71%). The qualitative analysis identified three different types of coping strategies (daily monitoring or vigilance, communication and planning) and four main areas of individuals' lives that are impacted by peanut allergy (social activities, relationships, emotions and work [adults and caregivers only]). The extent of the impact reported varied substantially between participants, with some reporting many negative consequences of living with peanut allergy and others feeling it has minimal impact on their health-related quality of life. This large survey and interview study highlight the psychosocial burden of peanut allergy for adults, teenagers, children and caregivers in the UK and Ireland. The analysis demonstrates the wide variation in level of impact of peanut allergy and the unmet need for those individuals who experience a substantial burden from living with peanut allergy