Perceived Body Size Research Articles

Auditory Perceptual History Is Propagated through Alpha Oscillations.

SummaryPerception is a proactive, “predictive” process, in which the brain relies, at least in part, on accumulated experience to make best guesses about the world to test against sensory data, updating the guesses as new experience is acquired. Using novel behavioral methods, the present study demonstrates the role of alpha rhythms in communicating past perceptual experience. Participants were required to discriminate the ear of origin of brief sinusoidal tones that were presented monaurally at random times within a burst of uncorrelated dichotic white noise masks. Performance was not constant but varied with delay after noise onset in an oscillatory manner at about 9 Hz (alpha rhythm). Importantly, oscillations occurred only for trials preceded by a target tone to the same ear, either on the previous trial or two trials back. These results suggest that communication of perceptual history generates neural oscillations within specific perceptual circuits, strongly implicating behavioral oscillations in predictive perception and with formation of working memory.

Impact of perceptions of body size on obesity and weight management behaviour: a large representative population study in an African setting.

Perception of body size is an important psycho-cultural cause of obesity with wide racial and ethnic variations. Cross-sectional household survey using multistage cluster-randomised sampling. Prevalence estimates were weighted. Logistic regressions were done to determine the impact of perception of large body size on obesity and the impact of perception of own body size on weight-management behaviour. Adjusted odds ratios (AOR) were reported. The survey involved 6628 adults from 2843 households. More than a quarter of the population is either obese or overweight. Nearly half, 44.07% (95% confidence interval [CI]: 42.48-45.66%) of the population perceive large body size as desirable. Positive perception of large body size significantly increases the odds of obesity by 1.5 (AOR: 1.45; 95% CI: 1.09-1.9). Some 42.03% (95% CI: 35.52-48.55%) obese persons misperceive their weight to be normal. Perceiving own body size as normal decreases the odds of weight-losing behaviour (AOR: 0.019; 95% CI: 0.014-0.026). There is a high level of veneration of large body size in southeast Nigeria, and this has a significant impact on obesity burden. Perception of own body size has a significant impact on weight-management behaviour. Health-promotion policies aimed at changing the social desirability of large body size and misperception of body size are recommended.

Accuracy of Body Size Estimation in Youth with Cystic Fibrosis and Association with Health-Related Quality of Life.

Accuracy of body size estimation may impact motivation to adhere to treatment recommendations and health-related quality of life (HRQOL) in youth with cystic fibrosis (CF), but this has not yet been investigated. Thus, the goal of the current study was to examine accuracy of body size estimation in youth with CF, and associations with HRQOL, lung functioning, and dietary intake. Fifty-four youth diagnosed with CF (M = 13.61years) completed the Figure Rating Scale, the Cystic Fibrosis Questionnaire-Revised, and a 24-h diet recall interview. Cohen's Weighted Kappa Coefficient evaluated agreement between body size estimation and BMI percentile. Binary logistic regression analyses examined associations between body size accuracy and HRQOL, lung functioning, and dietary intake. A less than adequate agreement was found between youth body size estimation and BMI percentile. Most participants overestimated body size (69.8%). Body Image HRQOL, but neither lung functioning nor dietary intake, was significantly associated with body size estimation accuracy. Working with patients to improve perceptions of body size may also improve HRQOL scores and allow for discussion about treatment goals related to body size.

An Assessment of Computer-Generated Stimuli for Use in Studies of Body Size Estimation and Bias.

Inaccurate body size judgments are associated with body image disturbances, a clinical feature of many eating disorders. Accordingly, body-related stimuli have become increasingly important in the study of estimation inaccuracies and body image disturbances. Technological advancements in the last decade have led to an increased use of computer-generated (CG) body stimuli in body image research. However, recent face perception research has suggested that CG face stimuli are not recognized as readily and may not fully tap facial processing mechanisms. The current study assessed the effectiveness of using CG stimuli in an established body size estimation task (the “bodyline” task). Specifically, we examined whether employing CG body stimuli alters body size judgments and associated estimation biases. One hundred and six 17- to 25-year-old females completed the CG bodyline task, which involved estimating the size of full-length CG body stimuli along a visual analogue scale. Our results show that perception of body size for CG stimuli was non-linear. Participants struggled to discriminate between extreme bodies sizes and overestimated the size change between near to average bodies. Furthermore, one of our measured size estimation biases was larger for CG stimuli. Our collective findings suggest using caution when employing CG stimuli in experimental research on body perception.

PREDICTORS OF OVERWEIGHT AND OBESITY AMONG SECONDARY SCHOOL STUDENTS IN PUCHONG SELANGOR, MALAYSIA

Background: Childhood obesity is gaining a dramatic increase in developing as well as in developed countries. Childhood overweight and obesity in which adolescents are included have be known to have negative impact on both physical and psychological health. Overweight and obese children are likely to stay obese into their adulthood and are more likely to develop non-communicable diseases . The objective of this study is to determine the occurrence and factors associated with overweight and obesity among secondary school students in Puchong Selangor Malaysia. Materials and Method: A cross-sectional study design was employed. A self-constructed pretested questionnaire was used for the data collection. The questionnaire consists of six sections, which include: socio-demography characteristics, physical activity questionnaire, self-esteem scale, body parts satisfaction scale, body size perception scale and smoking status questionnaire. Weight and height were measured and converted to body mass index (BMI). The study analysis was done using SPSS version 22. Basic descriptive analyses were carried out for the mean, median, frequency and percentage. Chi square test was used to test association between the variables. Multiple logistic regressions were used to determine the predictors of overweight and obesity among the respondents. Result: The response rate was 100%. The respondents’ age was 13-17years and occurrence of overweight and obesity was 10% and 3.9% respectively. Out of the 281 students that participated in the study 164 were female (58.4%). Overweight and obesity was significantly associated with father’s education ( χ2 = 9.697, df= 2, p =0.006), mothers education ( χ2 = 7.448, df= 2, p = 0.023), body part satisfaction ( χ2 =14.837, df= 1, p = 0.001) and body image ( χ2 =6.745, df= 1, p = 0.009). Multiple logistic regression analysis showed that the predictors of obesity were age (AOR=2.049, 95% CL: 0.186, 0.835, p <0.007), body parts satisfaction (AOR=3.656, 95% CL: 1.729, 7.730, p <0.001) and body size perception (AOR=3.130, 95%:1.269, 7.718, p <0.014). Conclusion: The significant predictors of overweight and obesity among study population were age, body parts satisfaction and body size perception. Keywords: Overweight, obesity, association, predictors, secondary school, students.

Caloric vestibular stimulation has no effect on perceived body size

It has been suggested that the vestibular system not only plays a role for our sense of balance and postural control but also might modulate higher-order body representations, such as the perceived shape and size of our body. Recent findings using virtual reality (VR) to realistically manipulate the length of whole extremities of first person biometric avatars under vestibular stimulation did not support this assumption. It has been discussed that these negative findings were due to the availability of visual feedback on the subjects’ virtual arms and legs. The present study tested this hypothesis by excluding the latter information. A newly recruited group of healthy subjects had to adjust the position of blocks in 3D space of a VR scenario such that they had the feeling that they could just touch them with their left/right hand/heel. Caloric vestibular stimulation did not alter perceived size of own extremities. Findings suggest that vestibular signals do not serve to scale the internal representation of (large parts of) our body’s metric properties. This is in obvious contrast to the egocentric representation of our body midline which allows us to perceive and adjust the position of our body with respect to the surroundings. These two qualia appear to belong to different systems of body representation in humans.

Body image in relation to nutritional status in adults from the Basque Country, Spain.

The aim of this research was to analyse variation in body image perception and satisfaction by age, sex and nutritional status in an adult sample from the Basque Country, Spain. A case-control study was performed for 227 women and 178 men aged 18-70 years. Stunkard's silhouettes were used to evaluate Current Body Image (CBI) and Ideal Body Image (IBI), as well as dissatisfaction and inconsistency scores. Nutritional status was assessed following the WHO criteria for BMI in an adult population. The sample was divided into four groups based on sex and age (early adulthood <45 years, and middle/older adulthood ≥45 years). The Mann-Whitney U test was employed to evaluate sex and age differences, and the Gamma coefficient to assess the association between body image variables and nutritional status. Significant age differences in CBI (p<0.05) and sex differences in IBI (p<0.001) were detected. Both variables showed a positive association with BMI (p<0.01), which indicates that BMI is a biological characteristic related to body image satisfaction and influences participants' perception of themselves. Dissatisfaction scores showed that both sex and age differences (p<0.05) were negatively associated with BMI (p<0.001). Only participants ≥45 years presented sex differences in inconsistency scores (p<0.05); this variable was associated with BMI in women (p<0.01). Preferences in body image showed sexual dimorphism, with women preferring thinner bodies than men - a pattern observed in many Western populations - linked in part to sociocultural pressures. Women were more dissatisfied with their bodies than men; a higher dissatisfaction was observed in older relative to younger participants. The results confirm the association between nutritional status and body size perception and satisfaction, but also the relationship between nutritional status and the reliability with which women can classify themselves; in men, this relationship was not as clear.

Suicidal ideation in relation to disordered eating, body size and weight perception: a cross-sectional study of a Norwegian adolescent population: the HUNT Study

ObjectiveWe conducted a population-based study on a sample of more than 7000 adolescents where we examined the associations between suicidal ideation (SI) and disordered eating (DE) and its related traits.DesignCross-sectional.SettingsData...

Body Size Perceptions of Women and Obesity in Urban Uganda

Body Size Perceptions of Women and Obesity in Urban Uganda

Body Size Preferences and Food Choice Among Normal and Overweight Mothers and Children in Malawi (P10-070-19)

ObjectivesOverweight in mothers and children in sub-Saharan Africa is rapidly increasing and may be related to body size preferences. The objective of this study was to measure mothers’ preferences for their own and their child’s body size and how they relate to food choices. MethodsWe enrolled 271 mothers and their children (6–59 months) in Lilongwe and Kasungu Districts. Based on standard body-mass index and weight-for-height z-score cutoffs, 78 mothers (29%) were normal weight and 193 (71%) were overweight; 120 children (44%) were normal weight and 151 (56%) were overweight. Interviewers used a set of 7 adult female and 7 child body silhouette drawings and a semi-structured question guide to measure mothers’ perceptions of their own and their child’s preferred and healthy body sizes and how their preferences affected food choices. We performed chi-squared tests comparing body size perceptions and grouped open-ended responses by weight status. ResultsMothers’ selection of silhouettes that represented their body size preferences (67% normal weight, 68% overweight preferred overweight) and perceptions of a healthy body size (96% normal weight, 94% overweight selected overweight as healthy) did not differ by their weight status. A higher percentage of mothers of overweight than normal weight children preferred overweight child body sizes (70% vs. 48%, P = 0.003). Mothers’ perceptions of a healthy child body size (89% normal weight, 94% overweight selected overweight as healthy) did not differ by the child’s weight status. To attain a larger body size, mothers said they could eat or feed the child larger quantities or more frequently and increase consumption of fatty/oily foods and drinks (such as sodas, sweetened yoghurt, and milk), but many cannot afford to do this. ConclusionsMalawian mothers had strong preferences for overweight body sizes for themselves and mixed preferences for their children. Their desired strategies for increasing weight indicate that body size preferences may drive food choice but could be limited by cost. Funding SourcesDrivers of Food Choice (DFC) Competitive Grants Program, funded by the UK Government’s Department for International Development and the Bill & Melinda Gates Foundation, and managed by the University of South Carolina, Arnold School of Public Health.

Influence Of Menarche On Perception, Dimension And Body Image Of Active And Insufficiently Active Girls

Menarche causes body changes such as increased body fat and classic changes occur in secondary sexual characteristics. In this way due to body changes, the body perception also needs to be adjusted. The regular practice of physical activity has been considered a key element to improve the perception of size and body image in different populations, however, to our knowledge, the association between menarche and the level of physical activity in perception of the dimension and of the body image still unexplored. PURPOSE: Verify the influence of menarche in the perception of the dimension and the body image of active and inactive girls. METHODS: After the approval of the São Judas Tadeu University Research Ethics Committee, thirty-eight girls were distributed into two groups active and insufficiently active subjects and analyzed semiannually by 2,5 years by identification before and after menarche. Anthropometric parameters (height, body weight and body mass index), perceptions of body size (using the Image Marking Procedure) and body image (silhouettes scale) were used as evaluation parameters. RESULTS: After menarche, all the girls in both groups presented alteration (p <0.05) only in the anthropometric parameters and in the body perception index of the hip after the menarche. No significant changes were identified (p> 0.05) between groups. CONCLUSION: menarche induced anthropometric alterations and perception of the hip dimension, but without promoting changes in the general perception of the body, as well as in the indication of the silhouettes and in the corporal satisfaction regardless of the level of activity physical.

Deep Brain Stimulation as a Treatment Approach for Anorexia Nervosa: a Systematic Literature Review

AbstractAnorexia nervosa is a psychiatric disorder characterized by distortions of body size, weight, and shape perception, as well as by food restriction and/or binge and purging behaviors. It mostly affects young women and causes severe negative impacts on their physical, psychological, and social health. Recent studies have analyzed deep brain stimulation (DBS), a neurosurgical procedure that involves electrode implantation in strategical brain areas, to obtain remission of the symptoms of anorexia nervosa. The results showed that the stimulation of areas associated to the neurocircuitry of anorexia nervosa, such as nucleus accumbens, anterior cingulate cortex, ventral striatum, and bed nucleus of the stria terminalis, provokes beneficial responses in terms of body mass index, quality of life, social functioning, and psychiatric comorbidities. Nevertheless, broader investigations are needed to endorse the clinical usage of DBS in the management of anorexia nervosa.

Perceptual Not Attitudinal Factors Predict the Accuracy of Estimating Other Women's Bodies in Both Women With Anorexia Nervosa and Controls.

Disturbance in how one’s body shape and size is experienced, usually including over-estimation of one’s own body size, is a core feature of the diagnostic criteria of anorexia nervosa (AN). Is this over-estimation specific to women with AN’s judgments of their own body? Or is it just a general feature of their judgments about all bodies? If the latter, it would be consistent with a general error in the perception of body size potentially linked to the use of a different set of visual cues for judging body size. If the former, then this suggests that the over-estimation of own body size has a strong attitudinal component and may be part of the psycho-pathology of their condition. To test this hypothesis, 20 women with AN and 80 control observers estimated the body size of 46 women. The results show a strong effect of perceptual factors in estimating body size for both controls and women with AN. This result is consistent with size over-estimation of own body in AN having a strong attitudinal basis and being a core feature of the psycho-pathology of the condition.

Somatosensory cortical representation of the body size.

The knowledge of the size of our own body parts is essential for accurately moving in space and efficiently interact with objects. A distorted perceptual representation of the body size often represents a core diagnostic criterion for some psychopathological conditions. The metric representation of the body was shown to depend on somatosensory afferences: local deafferentation indeed causes a perceptual distortion of the size of the anesthetized body part. A specular effect can be induced by altering the cortical map of body parts in the primary somatosensory cortex. Indeed, the present study demonstrates, in healthy adult participants, that repetitive Transcranial Magnetic Stimulation to the somatosensory cortical map of the hand in both hemispheres causes a perceptual distortion (i.e., an overestimation) of the size of the participants' own hand (Experiments 1-3), which does not involve other body parts (i.e., the foot, Experiment 2). Instead, the stimulation of the inferior parietal lobule of both hemispheres does not affect the perception of the own body size (Experiment 4). These results highlight the role of the primary somatosensory cortex in the building up and updating of the metric of body parts: somatosensory cortical activity not only shapes our somatosensation, it also affects how we perceive the dimension of our body.

Body Image Perception among Adolescent students in a private School in Thrissur, Kerala

Introduction: Body image perception is the way a person feels about his/her body and these feelings can be positive, negative or both. It is ever changing, and is influenced by individual and environmental factors. It can be both self-perceived or as perceived by others like family, friends, peer group, teachers etc. Objectives: To assess the body image perception of adolescents and the associated factors and to assess the effect of family, friends, peers and others on the body image perception of adolescents. Methodology: This was a cross sectional study. Four divisions from classes 9, 10, 11 and 12 of a private school, Thrissur were randomly selected. There were 179 students in total. A pretested self administered questionnaire was used to collect data. Results: The proportion of boys (50.3%) and girls (49.7%) were almost equal. In this study 65.4% of the adolescents were having normal BMI for their age.26.2% of the subjects had overweight and 8.4% of the subjects were undernourished. Varying degrees of negative body image perception was seen among 84.91% of subjects. Erroneous body size perception was seen among 36.8% of the subjects. This was statistically significant. A larger proportion of females (40.4%) compared to males (23.4%) was dissatisfied by their body size. Mean BMI was significantly higher in those who were not satisfied with their body size and those who had tried to lose weight in their past. Negative correlation was observed between body image perception and academic performance of the students. Conclusion: A high proportion of adolescents had negative body image perception. Targeted activities have to be carried out to improve their perception.

Visual perception of one's own body under vestibular stimulation using biometric self-avatars in virtual reality.

Background and purposeVestibular input is projected to "multisensory (vestibular) cortex" where it converges with input from other sensory modalities. It has been assumed that this multisensory integration enables a continuous perception of state and presence of one’s own body. The present study thus asked whether or not vestibular stimulation may impact this perception.MethodsWe used an immersive virtual reality setup to realistically manipulate the length of extremities of first person biometric avatars. Twenty-two healthy participants had to adjust arms and legs to their correct length from various start lengths before, during, and after vestibular stimulation.ResultsNeither unilateral caloric nor galvanic vestibular stimulation had a modulating effect on the perceived size of own extremities.ConclusionOur results suggest that vestibular stimulation does not directly influence the explicit somatosensory representation of our body. It is possible that in non-brain-damaged, healthy subjects, changes in whole body size perception are principally not mediated by vestibular information. Alternatively, visual feedback and/or memory may dominate multisensory integration and thereby override possibly existing modulations of body perception by vestibular stimulation. The present observations suggest that multisensory integration and not the processing of a single sensory input is the crucial mechanism in generating our body representation in relation to the external world.

The effect of exposure to thin models and digital modification disclaimers on women's body satisfaction.

This study tests the effectiveness of public health initiatives aimed at reducing the adverse effects of exposure to thin images in advertising on women's body satisfaction. Using an online experiment with 195 Israeli adult women, we test the effects of message factors that are expected to influence body satisfaction-the model's body size, and the presence and size of disclaimers. Compared with advertisements featuring a thin model, exposure to an average sized model was indirectly and positively associated with body size satisfaction, through the perception of the model's body size. However, exposure to disclaimers regarding digital modification of the model did not influence body satisfaction. Moreover, irrespective of whether they were exposed to a disclaimer or not, most participants who viewed ads featuring thin models thought that the image had been digitally modified. The results call for further research on the effectiveness of disclaimer labels for promoting body satisfaction.

Dietary Diversity, Food Security, and Body Image among Women and Children on San Cristobal Island, Galapagos.

We conducted a study of the food environment and nutritional status among women and children living on a Galapagos Island. Anthropometric and body silhouette data give insight into body size perceptions for women and their young children. We frame our findings in the context of the nutrition transition. A convenience sample was recruited via word-of-mouth for in-depth interviews and assessments of household food security, dietary intake, anthropometrics, and body image. Interviews took place in 2011 on San Cristobal Island, one of four inhabited islands in the Galapagos archipelago. Twenty women with children between the ages of one and six participated, all permanent residents of San Cristobal Island. Most women (60%) reported limited availability of fresh produce due to an unreliable food supply shipped from mainland Ecuador. Despite reported food insecurity in our sample (55%), more than half of the children (55%) experienced high dietary diversity measured by 24h recall. Women tended to report less dietary diversity than their children, which may be linked to a stated desire to be thinner. Eighty percent of children were classified as normal weight, while 75% of women were overweight or obese. Conclusions for Practice: Results provide an initial survey of the food landscape on one Galapagos Island. By combining qualitative interviews with indicators of nutritional status, the narrative data allow an interpretation of issues of food security, dietary intakes, dietary diversity, and body size. This study forms the basis for a larger examination of these issues in the Galapagos islands.

Objective versus subjective comparisons of body size against thin media models, media pressures, internalization, and body satisfaction

This study examined associations among the objective and subjective comparisons of one’s own body versus thin media models, media pressure, internalization, and body satisfaction. Korean females aged between 20 and 39 years (n=300) completed an online self-report questionnaire incorporating measures of these constructs. Body mass index (BMI) and perceived body size similarity to thin media models were used to measure objective and subjective comparisons of one’s own body to the thin bodies of media models. When both BMI and perceived body size similarity were tested simultaneously, only perceived body size similarity was found to be a significant predictor of media pressure. Results suggest that the subjective comparison to thin media models is a more powerful determinant of women’s body image than objective comparison. Internalization was associated with body satisfaction and mediated the impact of media pressure on body satisfaction.

Defective Tool Embodiment in Body Representation of Individuals Affected by Parkinson's Disease: A Preliminary Study.

When efficiently used for action, tools become part of the body, with effect on the spatial-temporal movement parameters and body size perception. Until now, no previous investigation has been reported about tool embodiment in Parkinson’s disease (PD), which is a neurological disease characterized by several sensory and motor symptoms affecting body and action. We enrolled 14 individuals affected by PD and 18 healthy individuals as controls. We studied the spatial-temporal parameters on self-paced free pointing movement task, via an optoelectronic system, before and after a short training in which a 27-cm long rod was used to point toward a far target. Moreover, we investigated changes in estimation of arm length through the Tactile Estimation Task. After the tool-use training, controls showed changes in spatial-temporal parameters: they were slower to perform movements and reported a higher value of deceleration than the baseline. However, such a difference did not emerge in the PD individuals. In the Tactile Discrimination Task, no difference emerged before and after the tool-use training in both groups. Our results were suggestive of possible difficulties of the tool embodiment process in PD. We discussed our results in relation to aberrant multisensory integration as well as in terms of the effect of PD sensory and motor symptoms on body schema plasticity. The present study points at a novel way to conceive PD sensory motor signs and symptoms in terms of their effect on individuals’ body representation.