Craving is everything: An eye-tracking exploration of attentional bias in binge drinking

Attentional Bias, Pupillometry, and Spontaneous Blink Rate: Eye Characteristic Assessment Within a Translatable Nicotine Cue Virtual Reality Paradigm

Background

Incentive salience processes are important for the development and maintenance of addiction. Eye characteristics such as gaze fixation time, pupil diameter, and spontaneous eyeblink rate (EBR) are theorized to reflect incentive salience and may serve as useful biomarkers. However, conventional cue exposure paradigms have limitations that may impede accurate assessment of these markers.

Objective

This study sought to evaluate the validity of these eye-tracking metrics as indicators of incentive salience within a virtual reality (VR) environment replicating real-world situations of nicotine and tobacco product (NTP) use.

Methods

NTP users from the community were recruited and grouped by NTP use patterns: nondaily (n=33) and daily (n=75) use. Participants underwent the NTP cue VR paradigm and completed measures of nicotine craving, NTP use history, and VR-related assessments. Eye-gaze fixation time (attentional bias) and pupillometry in response to NTP versus control cues and EBR during the active and neutral VR scenes were recorded and analyzed using ANOVA and analysis of covariance models.

Results

Greater subjective craving, as measured by the Tobacco Craving Questionnaire-Short Form, following active versus neutral scenes was observed (F1,106=47.95; P<.001). Greater mean eye-gaze fixation time (F1,106=48.34; P<.001) and pupil diameter (F1,102=5.99; P=.02) in response to NTP versus control cues were also detected. Evidence of NTP use group effects was observed in fixation time and pupillometry analyses, as well as correlations between these metrics, NTP use history, and nicotine craving. No significant associations were observed with EBR.

Conclusions

This study provides additional evidence for attentional bias, as measured via eye-gaze fixation time, and pupillometry as useful biomarkers of incentive salience, and partially supports theories suggesting that incentive salience diminishes as nicotine dependence severity increases.

An advance in novel intelligent sensory technologies: From an implicit-tracking perspective of food perception

Food sensory evaluation mainly includes explicit and implicit measurement methods. Implicit measures of consumer perception are gaining significant attention in food sensory and consumer science as they provide effective, subconscious, objective analysis. A wide range of advanced technologies are now available for analyzing physiological and psychological responses, including facial analysis technology, neuroimaging technology, autonomic nervous system technology, and behavioral pattern measurement. However, researchers in the food field often lack systematic knowledge of these multidisciplinary technologies and struggle with interpreting their results. In order to bridge this gap, this review systematically describes the principles and highlights the applications in food sensory and consumer science of facial analysis technologies such as eye tracking, facial electromyography, and automatic facial expression analysis, as well as neuroimaging technologies like electroencephalography, magnetoencephalography, functional magnetic resonance imaging, and functional near-infrared spectroscopy. Furthermore, we critically compare and discuss these advanced implicit techniques in the context of food sensory research and then accordingly propose prospects. Ultimately, we conclude that implicit measures should be complemented by traditional explicit measures to capture responses beyond preference. Facial analysis technologies offer a more objective reflection of sensory perception and attitudes toward food, whereas neuroimaging techniques provide valuable insight into the implicit physiological responses during food consumption. To enhance the interpretability and generalizability of implicit measurement results, further sensory studies are needed. Looking ahead, the combination of different methodological techniques in real-life situations holds promise for consumer sensory science in the field of food research.

Exploring Attentional Bias toward Alcohol Content: Insights from Eye-Movement Activity

INTRODUCTION

Attentional bias (AB) is an implicit selective attention toward processing disorder-significant information while neglecting other environmental cues. Considerable empirical evidence highlights the clinical implication of AB in the onset and maintenance of substance use disorder. An innovative method to explore direct measures of AB relies on the eye-movement activity using technologies like eye-tracking (ET). Despite the growing interest regarding the clinical relevance of AB in the spectrum of alcohol consumption, more research is needed to fully determine the AB patterns and its transfer from experimental to clinical applications. The current study consisted of three consecutive experiments. The first experiment aimed to design an ad-hoc visual attention task (VAT) consisting of alcohol-related and neutral images using a nonclinical sample (n = 15). The objective of the second and third experiments was to analyze whether the effect of type of image (alcohol-related vs. neutral images) on AB toward alcohol content using the VAT developed in the first experiment was different for type of drinker (light vs. heavy drinker in the second experiment [n = 30], and occasional social drinkers versus alcohol use disorder (AUD) patients in the third experiment [n = 48]).

METHODS

Areas of interest (AOIs) within each type of image (neutral and alcohol-related) were designed and raw ET-based data were subsequently extracted through specific software analyses. For experiment 1, attention maps were created and processed for each image. For experiments 2 and 3, data on ET variables were gathered and subsequently analyzed through a two-way ANOVA with the aim of examining the effects of the type of image and drinker on eye-movement activity.

RESULTS

There was a statistically significant interaction effect between type of image and type of drinker (light vs. heavy drinker in experiment 2, F(1, 56) = 13.578, p < 0.001, partial η2 = 0.195, and occasional social drinker versus AUD patients in the experiment 3, F(1, 92) = 35.806, p < 0.001, partial η2 = 0.280) for "first fixation" with large effect sizes, but not for "number of fixations" and "dwell time." The simple main effect of type of image on mean "first fixation" score for AUD patients was not statistically significant.

CONCLUSION

The data derived from the experiments indicated the importance of AB in sub-clinical populations: heavy drinkers displayed an implicit preference for alcohol-related images compared to light drinkers. Nevertheless, AB fluctuations in patients with AUD compared to the control group were found. AUD patients displayed an early interest in alcohol images, followed by an avoidance attentional processing of alcohol-related images. The results are discussed in light of recent literature in the field.

Craving modulates attentional bias towards alcohol in severe alcohol use disorder: An eye-tracking study

BACKGROUND AND AIMS

Competing models disagree on three theoretical questions regarding alcohol-related attentional bias (AB), a key process in severe alcohol use disorder (SAUD): (1) is AB more of a trait (fixed, associated with alcohol use severity) or state (fluid, associated with momentary craving states) characteristic of SAUD; (2) does AB purely reflect the over-activation of the reflexive/reward system or is it also influenced by the activity of the reflective/control system and (3) does AB rely upon early or later processing stages? We addressed these issues by investigating the time-course of AB and its modulation by subjective craving and cognitive load in SAUD.

DESIGN

A free-viewing eye-tracking task, presenting pictures of alcoholic and non-alcoholic beverages, combined with a concurrent cognitive task with three difficulty levels.

SETTING

A laboratory setting in the detoxification units of three Belgian hospitals.

PARTICIPANTS

We included 30 patients with SAUD self-reporting craving at testing time, 30 patients with SAUD reporting a total absence of craving and 30 controls matched on sex and age. All participants from SAUD groups met the DSM-5 criteria for SAUD.

MEASUREMENTS

We assessed AB through early and late eye-tracking indices. We evaluated the modulation of AB by craving (comparison between patients with/without craving) and cognitive load (variation of AB with the difficulty level of the concurrent task).

FINDINGS

Dwell time measure indicated that SAUD patients with craving allocated more attention towards alcohol-related stimuli than patients without craving (P < 0.001, d = 1.093), resulting in opposite approach/avoidance AB according to craving presence/absence. SAUD patients without craving showed a stronger avoidance AB than controls (P = 0.003, d = 0.806). AB did not vary according to cognitive load (P = 0.962, η2 p  = 0.004).

CONCLUSIONS

The direction of alcohol-related attentional bias (approach/avoidance) appears to be determined by patients' subjective craving at testing time and does not function as a stable trait of severe alcohol use disorder. Alcohol-related attentional bias appears to rely on later/controlled attentional stages but is not modulated by the saturation of the reflective/control system.

Separating desire from prediction of outcome value

Individuals typically want what they expect to like, often based on memories of previous positive experiences. However, in some situations desire can decouple completely from memories and from learned predictions of outcome value. The potential for desire to separate from prediction arises from independent operating rules that control motivational incentive salience. Incentive salience, or 'wanting', is a type of mesolimbic desire that evolved for adaptive goals, but can also generate maladaptive addictions. Two proof-of-principle examples are presented here to show how motivational 'wanting' can soar above memory-based predictions of outcome value: (i) 'wanting what is remembered to be disgusting', and (ii) 'wanting what is predicted to hurt'. Consequently, even outcomes remembered and predicted to be negatively aversive can become positively 'wanted'. Similarly, in human addictions, people may experience powerful cue-triggered cravings for outcomes that are not predicted to be enjoyable.

Tell me how you feel, I will tell you what you look at: Impact of mood and craving on alcohol attentional bias in binge drinking

BACKGROUND

Alcohol-related attentional bias (AB) is thought to play a key role in the emergence and maintenance of excessive alcohol use. Recent models suggest that AB, classically considered as a permanent feature in alcohol use disorders, is rather modulated by temporary motivational states.

AIMS

We explored the influence of current mood and craving on AB in binge drinking, through a mood induction procedure combined with eye-tracking measures of AB.

METHODS

In Experiment 1, we measured AB (visual probe task with eye-tracking measures) among binge drinkers (n = 48) and light drinkers (n = 32) following positive, negative and neutral mood inductions. Participants reported subjective craving and mood before/after induction. In Experiment 2, we measured AB among the same binge drinkers compared with 29 moderate drinkers following alcohol-related negative, non-alcohol-related negative and neutral mood inductions.

RESULTS

In Experiment 1, induced negative mood and group positively predicted subjective craving, which was positively associated with AB. We found no effect of induced positive mood nor a direct mood-AB association. In Experiment 2, the relationships AB presented with both induced negative mood and group were again mediated by craving. Inducing alcohol-related negative mood did not modify the mood-craving association.

CONCLUSIONS

Alcohol-related AB is not a stable binge drinking characteristic but rather varies according to transient motivational (i.e., craving) and emotional (i.e., negative mood) states. This study provides important insights to better understand AB in subclinical populations and emphasizes the importance of considering motivational and affective states as intercorrelated, to offer multiple ways to reduce excessive alcohol use.

Does alcohol automatically capture drinkers' attention? Exploration through an eye-tracking saccadic choice task

RATIONALE

Dominant theoretical models postulate the presence of an automatic attentional bias (AB) towards alcohol-related stimuli in alcohol use disorder, such AB constituting a core feature of this disorder. An early alcohol AB has been documented in subclinical populations such as binge drinking (i.e., a drinking pattern prevalent in youth and characterized by repeated alternation between alcohol intoxications and withdrawals, generating cerebral consequences). However, the automatic nature of AB remains to be established.

OBJECTIVES

We investigated the automatic nature of AB in binge drinkers through the saccadic choice task. This eye-tracking paradigm consistently highlights the extremely fast and involuntary saccadic responses elicited by faces in humans, relative to other object categories. Through an alcohol-related adaptation of the saccadic choice task, we tested whether the early and automatic capture of attentional resources elicited by faces can also be found for alcohol-related stimuli in binge drinkers, as predicted by theoretical models.

METHODS

Forty-three binge drinkers and 44 control participants performed two versions of the saccadic choice task. In the original version, two images (a face, a vehicle) were displayed on the left and right side of the screen respectively. Participants had to perform a saccade as fast as possible towards the target stimulus (either face or vehicle). In the alcohol-related version, the task was identical, but the images were an alcoholic beverage and a non-alcoholic stimulus.

RESULTS

We replicated the automatic attraction towards faces in both groups, as faces generated higher saccadic accuracy, speed, and amplitude than vehicles, as well as higher corrective saccade proportion. Concerning the alcohol-related adaptation of the task, groups did not differ for the accuracy, speed, and amplitude of the first saccade towards alcohol. However, binge drinkers differed from controls regarding the proportion of corrective saccade towards non-alcoholic stimuli after an error saccade towards alcohol, suggesting the presence of an alcohol disengagement bias specific to binge drinkers.

CONCLUSIONS

Alcohol-related AB in binge drinkers is not characterized by an early and automatic hijacking of attention towards alcohol. This AB rather relies on later and more controlled processing stages, namely a difficulty to disengage attentional resources from alcohol-related stimuli.

Development and validation of a new methodological platform to measure behavioral, cognitive, and physiological responses to food interventions in real time

To fully understand the causes and mechanisms involved in overeating and obesity, measures of both cognitive and physiological determinants of eating behavior need to be integrated. Effectively synchronizing behavioral measures such as meal micro-structure (e.g., eating speed), cognitive processing of sensory stimuli, and metabolic parameters, can be complex. However, this step is central to understanding the impact of food interventions on body weight. In this paper, we provide an overview of the existing gaps in eating behavior research and describe the development and validation of a new methodological platform to address some of these issues. As part of a controlled trial, 76 men and women self-served and consumed food from a buffet, using a portion-control plate with visual stimuli for appropriate amounts of main food groups, or a conventional plate, on two different days, in a random order. In both sessions participants completed behavioral and cognitive tests using a novel methodological platform that measured gaze movement (as a proxy for visual attention), eating rate and bite size, memory for portion sizes, subjective appetite and portion-size perceptions. In a sub-sample of women, hormonal secretion in response to the meal was also measured. The novel platform showed a significant improvement in meal micro-structure measures from published data (13 vs. 33% failure rate) and high comparability between an automated gaze mapping protocol vs. manual coding for eye-tracking studies involving an eating test (ICC between methods 0.85; 90% CI 0.74, 0.92). This trial was registered at Clinical Trials.gov with Identifier NCT03610776.

Attentional bias in alcohol drinkers: A systematic review of its link with consumption variables

In severe alcohol use disorder (SAUD), attentional bias refers to the preferential allocation of attentional resources toward alcohol-related cues. Dominant models consider that this bias plays a key role in the emergence and maintenance of SAUD. We evaluate the available experimental support for this assumption through a systematic literature review, providing a critical synthesis of studies exploring the links between alcohol consumption and attentional bias. Using PRISMA guidelines, we explored three databases (PsycINFO, PubMed, Scopus) and extracted 95 papers. We assessed their methodological quality and categorized them based on the population targeted, namely patients with SAUD or subclinical populations with various drinking patterns. We also classified papers according to the measures used (i.e., behavioral or eye-tracking measures). Overall, subclinical populations present an alcohol-related bias, but many studies in SAUD did not find such bias, nor approach/avoidance patterns. Moreover, attentional bias fluctuates alongside motivational states rather than according to alcohol use severity, which questions its stability. We provide recommendations to develop further theoretical knowledge and overcome methodological shortcomings.

"It's a beer!": Brain functional hyperconnectivity during processing of alcohol-related images in young binge drinkers

Alcohol attentional bias has been pointed as a major marker of alcohol misuse. Recent evidence has revealed that brain functional connectivity (FC) may be a valuable index of the brain networks' integrity in young binge drinkers (BDs). However, there is no study to date examining the FC networks linked to the processing of alcohol-related images in this population. The present study aimed to explore the FC signatures underlying alcohol attention bias in young BDs. Thus, electroencephalographic (EEG) activity was recorded in 54 college students (55.5% females; 27 non/low-drinkers and 27 BDs) while performing a visual alcohol cue-reactivity task. We evaluated whole-brain FC profiles during the processing of alcoholic and non-alcoholic cues, as well as their potential relationship with craving and severity of alcohol use. Results showed that, at the behavioural level, BDs rated alcohol-related images as more pleasant/attractive than non/low-drinkers. Furthermore, at the electrophysiological level, BDs exhibited increased beta-band FC-particularly in the fronto-parieto-occipital network-when processing alcoholic cues. Conversely, they displayed reduced theta-band FC relatively to non/low-drinkers for non-alcoholic images. These hyper-/hypo-connectivity patterns were associated with higher alcohol craving levels. Findings are congruent with previous neurofunctional studies reporting an attentional bias towards alcohol-related information in BDs. These results may have important clinical implications as this neural reactivity to alcoholic cues may contribute to the maintenance and/or escalation of the drinking pattern. Finally, the present study constitutes the first evidence showing that FC networks may be a sensitive indicator to alcohol attentional bias in BDs.

Alcohol-related attentional biases in recently detoxified inpatients with severe alcohol use disorder: an eye-tracking approach

BACKGROUND

Dominant theoretical models consider that attentional biases (AB) towards alcohol-related stimuli play a key role in the development and maintenance of alcohol use disorder (AUD). Their assessment has however showed high inconsistencies and has been mostly based on unreliable behavioral measures. This study evaluated the presence and extent of alcohol-related AB in recently detoxified inpatients with severe AUD by combining the visual probe task (VPT) paradigm with eye-tracking measures, known to improve the VPT reliability in subclinical populations.

METHODS

We recruited 24 patients and 27 matched healthy controls. They performed the VPT (measuring reaction time when processing visual targets preceded by alcoholic and matched non-alcoholic pictures) combined with eye-tracking measures (dwell time, first fixation direction/duration, second fixation direction) during two sessions. Estimates of internal consistency, split-half reliability, and test-retest reliability were measured.

RESULTS

Patients showed shorter dwell time for alcohol cues (p = .004, d=.853) and reduced number of fixations towards alcohol after a first fixation on non-alcohol cues (p = .012, d=.758) compared to controls. These findings suggest the presence of alcohol-related avoidance AB in detoxified patients with severe AUD. The VPT achieved excellent reliability for these eye-tracking measures. Reaction times and first fixation measures did not indicate any AB pattern and showed poor reliability.

CONCLUSIONS

The VPT, when combined with dwell time and second fixation direction, constitutes a reliable method for assessing AB in detoxified patients. It showed the presence of an alcohol-related avoidance bias in this clinical population, in contradiction with the approach bias predicted by theoretical models.

Understanding Attentional Biases in Severe Alcohol Use Disorder: A Combined Behavioral and Eye-Tracking Perspective

RATIONALE

Severe alcohol use disorder (SAUD) is a psychiatric condition linked to cerebral and cognitive consequences. SAUD is notably characterized by an overactivation of the reflexive/reward system when confronted with alcohol-related cues. Such overreactivity generates a preferential allocation of attentional resources toward these cues, labeled as attentional biases (AB). Theoretical assumptions have been made regarding the characteristics of AB and their underlying processes. While often considered as granted, these assumptions remain to be experimentally validated.

AIMS

We first identify the theoretical assumptions made by previous studies exploring the nature and role of AB. We then discuss the current evidence available to establish their validity. We finally propose research avenues to experimentally test them.

METHODS

Capitalizing on a narrative review of studies exploring AB in SAUD, the current limits of the behavioral measures used for their evaluation are highlighted as well as the benefits derived from the use of eye-tracking measures to obtain a deeper understanding of their underlying processes. We describe the issues related to the theoretical proposals on AB and propose research avenues to test them. Four experimental axes are proposed, respectively, related to the determination of (a) the genuine nature of the mechanisms underlying AB; (b) their stability over the disease course; (c) their specificity to alcohol-related stimuli and (d) their reflexive or controlled nature.

CONCLUSIONS

This in-depth exploration of the available knowledge related to AB in SAUD, and of its key limitations, highlights the theoretical and clinical interest of our innovative experimental perspectives capitalizing on eye-tracking measures.

Electroencephalographic signatures of the binge drinking pattern during adolescence and young adulthood: A PRISMA-driven systematic review

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Controls and binge drinkers (BDs) do not differ in their behavioral performance.

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BDs show increased neural activity during attention, working memory and inhibition.

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Augmented P3 amplitude in BDs was the most solid electrophysiological finding.

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Evidence does not support specific gender vulnerabilities to the effects of BD.

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Memory, emotional processing and decision-making processes need further exploration.

Research on neurophysiological impairments associated with binge drinking (BD), an excessive but episodic alcohol use pattern, has significantly increased over the last decade. This work is the first to systematically review –following PRISMA guidelines- the empirical evidence regarding the effects of BD on neural activity –assessed by electroencephalography- of adolescents and young adults. A systematic review was conducted in 34 studies (N = 1723). Results indicated that binge drinkers (BDs) showed similar behavioral performance as non/low drinkers. The most solid electrophysiological finding was an augmented P3 amplitude during attention, working memory and inhibition tasks. This increased neural activity suggests the recruitment of additional resources to perform the task at adequate/successful levels, which supports the neurocompensation hypothesis. Similar to alcoholics, BDs also displayed increased reactivity to alcohol-related cues, augmented resting-state electrophysiological signal and reduced activity during error detection –which gives support to the continuum hypothesis. Evidence does not seem to support greater vulnerability to BD in females. Replication and longitudinal studies are required to account for mixed results and to elucidate the extent/direction of the neural impairments associated with BD.