Visual Attention to Pictorial Food Stimuli in Individuals With Night Eating Syndrome: An Eye-Tracking Study

Taking Steps Toward a Consensus on Night Eating Syndrome Diagnostic Criteria

BACKGROUND

Night eating syndrome (NES) is included in the Diagnostic and Statistical Manual for Mental Disorders, 5th edition, as an example of "Other Specified Feeding or Eating Disorders" with minimal guidance about how to define and operationalize NES. The literature suggests that research practices vary widely, making it difficult to draw conclusions about the public health burden of, effective interventions for, or policy implications relevant to NES. This Forum article seeks to illustrate the lack of definitional agreement to underscore the need for a consensus about NES diagnostic criteria, and to propose steps toward closing knowledge gaps and achieving consensus.

METHOD

We searched PubMed and PsycINFO titles and abstracts, using "NES" as the search term, for research articles published in English between January 1, 2013 to August 12, 2024 with sample sizes of NES > 10 and ages 18 or older. Eligible articles were coded for NES definitions and assessment method used to diagnose participants with NES and for information about comorbidity of NES and any other eating disorder (ED).

RESULTS

Seventy-three articles met inclusion criteria. Most commonly, NES was diagnosed using a diagnostic criteria set (35/73) or a symptom score threshold (34/73); among the former, only eight studies employed DSM-5 NES criteria. Thirteen studies, varying widely in methodology, examined comorbidity with other EDs, most commonly binge-eating disorder where comorbidity was high.

CONCLUSION

Heterogeneity of definitions and assessment impede progress in the study of NES. We propose strategies for developing a consensus definition and addressing research gaps.

Dynamic attentional bias for pictorial and textual food cues in the visual search paradigm

Previous studies have found that individuals have an attentional bias for food cues, which may be related to the energy level or the type of stimulus (e.g., pictorial or textual food cues) of the food cues. However, the available evidence is inconsistent, and there is no consensus about how the type of stimulus and food energy modulate food-related attentional bias. Searching for food is one of the most important daily behaviors. In this study, a modified visual search paradigm was used to explore the attentional bias for food cues, and eye movements were recorded. Food cues consisted of both food words and food pictures with different energy levels (i.e., high- and low-calorie foods). The results showed that there was an attentional avoidance in the early stage but a later-stage attentional approach for all food cues in the pictorial condition. This was especially true for high-calorie food pictures. Participants showed a later-stage conflicting attentional bias for foods with different energy levels in the textual condition. They showed an attentional approach to high-calorie food words but an attentional avoidance of low-calorie food words. These data show that food-related attentional bias varied along with different time courses, which was also modulated by the type of stimulus and food energy. These findings regarding dynamic attentional bias could be explained using the Goal Conflict Model of eating behavior.

Attentional vigilance of food information in disordered eating behaviors

INTRODUCTION

Disordered eating behaviors (DEBs) are very common among female college students, which seriously endanger their health and well-being. Therefore, the study of the mechanism of DEBs can provide effective evidence for early detection and intervention.

METHODS

In total of 54 female college students were recruited and assigned to DEB group (n = 29) and healthy control (HC) group (n = 25) according to their scores in the Eating Attitudes Test-26 (EAT-26). Then, the Exogenous Cueing Task (ECT) was used to evaluate their reaction time (RT) to the location of a target dot preceded by a food or neutral cue.

RESULTS

The study found that compared with HC group, DEB group showed more attentional engagement to food stimuli, indicating that attentional vigilance to food information could be considered as a specific attentional bias of DEBs.

DISCUSSION

Our findings not only provide evidence of the potential mechanism of DEBs from the perspective of attentional bias, but also can be considered as an effective and objective indicator for early screening of subclinical eating disorders (EDs).

Eating disorder-specific rumination moderates the association between attentional bias to high-calorie foods and eating disorder symptoms: Evidence from a reliable free-viewing eye-tracking task

Cognitive theories of eating disorders implicate Attentional Bias (AB) towards food-related information in the development and maintenance of eating disorders. Empirical evidence for this proposal, however, has been inconsistent, and the measures used to examine AB to food-related stimuli typically showed poor reliability. The aim of the current study was twofold. Firstly, we aimed to examine the psychometric properties of a newly devised eye-tracking task for the assessment of AB in the context of eating disorders. Secondly, we examined the role of Eating Disorder-specific (ED-specific) rumination as a potential moderator of the association between attentional bias to food images and eating disorder symptoms. One hundred and three female students were recruited and completed an eye-tracking task comprising 21 matrices that each contained 8 low-calorie and 8 high-calorie food images. Each matrix was presented for 6 s. First fixation location, first fixation latency, and total dwell time were assessed for low and high-calorie food images and the dwell-time based AB measure showed good reliability based on Cronbach's alpha, McDonald's Omega, and split-half method. In addition, the results revealed that the ED-specific rumination plays the hypothesized moderating role. Specifically, while participants with high levels of ED-specific rumination exhibited a positive association between AB to high-calorie foods and eating disorder symptoms, this association was not present among participants with lower levels of ED-specific rumination. The employed free-viewing task seems a reliable measure of AB to food-related stimuli, and the moderation analysis emphasizes the critical role of ED-specific rumination for eating disorder symptoms. Implications, limitations, and directions for future research are discussed.

Contribution of Eye-Tracking to Study Cognitive Impairments Among Clinical Populations

In the field of psychology, the merge of decision-theory and neuroscientific methods produces an array of scientifically recognized paradigms. For example, by exploring consumer’s eye-movement behavior, researchers aim to deepen the understanding of how patterns of retinal activation are being meaningfully transformed into visual experiences and connected with specific reactions (e.g., purchase). Notably, eye-movements provide knowledge of one’s homeostatic balance and gatekeep information that shape decisions. Hence, vision science investigates the quality of observed environments determined under various experimental conditions. Moreover, it answers questions on how human process visual stimuli and use gained information for a successful strategy to achieve certain goals. While capturing cognitive states with the support of the eye-trackers progresses at a relatively fast pace in decision-making research, measuring the visual performance of real-life tasks, which require complex cognitive skills, is tentatively translated into clinical experiments. Nevertheless, the potential of the human eye as a highly valuable source of biomarkers has been underlined. In this article, we aim to draw readers attention to decision-making experimental paradigms supported with eye-tracking technology among clinical populations. Such interdisciplinary approach may become an important component that will (i) help in objectively illustrating patient’s models of beliefs and values, (ii) support clinical interventions, and (iii) contribute to health services. It is possible that shortly, eye-movement data from decision-making experiments will grant the scientific community a greater understanding of mechanisms underlining mental states and consumption practices that medical professionals consider as obsessions, disorders or addiction.

Eating disorder symptoms and foraging for food related items

BACKGROUND

Foraging tasks have recently been increasingly used to investigate visual attention. Visual attention can be biased when certain stimuli capture our attention, especially threatening or anxiety-provoking stimuli, but such effects have not been addressed in foraging studies.

METHODS

We measured potential attentional bias associated with eating disorder symptoms to food related stimuli with our previously developed iPad foraging task. Forty-four participants performed a foraging task where they were instructed to tap predesignated food related targets (healthy and unhealthy) and other non-food objects and completed four self-report questionnaires measuring symptoms of eating disorders. Participants were split into two groups based on their questionnaire scores, a symptom group and no symptom group.

RESULTS

The foraging results suggest that there are differences between the groups on switch costs and target selection times (intertarget times) but they were only statistically significant when extreme-group analyses (EGA) were used. There were also notable food versus non-food category effects in the foraging patterns.

CONCLUSIONS

The results suggest that foraging tasks of this sort can be used to assess attentional biases and we also speculate that they may eventually be used to treat them through attention bias modification. Additionally, the category effects that we see between food items and other items are highly interesting and encouraging. At the same time, task sensitivity will need to be improved. Finally, future tests of clinical samples could provide a clearer picture of the effects of eating disorder symptoms on foraging for food.

Changes in visual attention towards food cues after obesity surgery: An eye-tracking study

Research documented the effectiveness of obesity surgery (OS) for long-term weight loss and improvements in medical and psychosocial sequelae, and general cognitive functioning. However, there is only preliminary evidence for changes in attentional processing of food cues after OS. This study longitudinally investigated visual attention towards food cues from pre- to 1-year post-surgery. Using eye tracking (ET) and a Visual Search Task (VST), attentional processing of food versus non-food cues was assessed in n = 32 patients with OS and n = 31 matched controls without weight-loss treatment at baseline and 1-year follow-up. Associations with experimentally assessed impulsivity and eating disorder psychopathology and the predictive value of changes in visual attention towards food cues for weight loss and eating behaviors were determined. During ET, both groups showed significant gaze duration biases to non-food cues without differences and changes over time. No attentional biases over group and time were found by the VST. Correlations between attentional data and clinical variables were sparse and not robust over time. Changes in visual attention did not predict weight loss and eating disorder psychopathology after OS. The present study provides support for a top-down regulation of visual attention to non-food cues in individuals with severe obesity. No changes in attentional processing of food cues were detected 1-year post-surgery. Further studies are needed with comparable methodology and longer follow-ups to clarify the role of biased visual attention towards food cues for long-term weight outcomes and eating behaviors after OS.

A systematic and methodological review of attentional biases in eating disorders: Food, body, and perfectionism

OBJECTIVE

The current systematic and methodological review aimed to critically review existing literature utilizing implicit processing, or automatic approach- and/or avoidance-related attentional biases between eating disorder (ED) and nonclinical samples, which (a) highlights how psychophysiological methods advance knowledge of ED implicit bias; (b) explains how findings fit into transdiagnostic versus disorder-specific ED frameworks; and (c) suggests how research can address perfectionism-related ED biases.

METHOD

Three databases were systematically searched to identify studies: PubMed, Scopus, and PsychInfo electronic databases. Peer-reviewed studies of 18- to 39-year-olds with both clinical ED and healthy samples assessing visual attentional biases using pictorial and/or linguistic stimuli related to food, body, and/or perfectionism were included.

RESULTS

Forty-six studies were included. While behavioral results were often similar across ED diagnoses, studies incorporating psychophysiological measures often revealed disease-specific attentional biases. Specifically, women with bulimia nervosa (BN) tend to approach food and other body types, whereas women with anorexia nervosa (AN) tend to avoid food as well as overweight bodies.

CONCLUSIONS

Further integration of psychophysiological and behavioral methods may identify subtle processing variations in ED, which may guide prevention strategies and interventions, and provide important clinical implications. Few implicit bias studies include male participants, investigate binge-eating disorder, or evaluate perfectionism-relevant stimuli, despite the fact that perfectionism is implicated in models of ED.

Eye-tracking research in eating disorders: A systematic review

OBJECTIVE

Those with eating disorders (EDs) show attentional biases to disorder-relevant stimuli, such as food and body shape information. However, attentional bias research in EDs largely relies on reaction time based measures, which are limited in their ability to assess different components and the time course of attention. Eye-tracking paradigms have therefore been utilized to provide greater ecological validity, and directly capture the detailed sequence of processes in perception and attention. While numerous studies have examined eye movements in the mood, anxiety, and psychotic disorders, there has been a lack of studies in EDs. The purpose of this qualitative review is to provide a summary of eye-tracking studies in clinical ED populations.

METHOD

The review was conducted using the PRISMA guidelines. Electronic databases were systematically searched to identify studies examining gaze parameters in ED compared to healthy controls (HCs). Thirty-one studies met inclusion criteria.

RESULTS

Across ED diagnoses, there was evidence of attentional biases towards food and body stimuli. In addition, differential patterns of attention to social information, and differences in smooth pursuit and saccadic eye movements were found in anorexia nervosa (AN).

DISCUSSION

Findings are discussed in relation to research in other psychiatric disorders, and recommendations for future studies using eye-tracking in EDs are given. The findings add to the wider literature on attentional biases in EDs, and provide potential avenues for treatment. IJED-18-0331.R1. Investigación de seguimiento ocular en trastornos de la conducta alimentaria: una revisión sistemática.