An Eye Movement Study Of Attention Bias In Obsessive-Compulsive Tendency Individuals With Contamination Fear

As a type of anxiety disorders, obsessive compulsive disorder(OCD) is defined by persistent, unwanted thoughts or impulses(obsessions) that motivate rigid, excessive behaviors(compulsions) aimed at undoing obsession related harm. Patients are usually aware of these thoughts or impulses deriving from their own and trying to resist, but always can’t control, then resulting in intense inner conflict and compulsive behavior to make them feel outpouring anxious and torture, that seriously affecting patients’ work,study, interpersonal communication, and even daily life. Compared with high prevalence rate of OCD, its’ cure rate is very low yet, up to now, there still has no effective treatment method can fully cure OCD, peering into one of the reasons is that the etiological process of OCD is unclear.Cognitive neuroscience researches have shown that people with OCD may exist cognitive dysfunction. Related cognitive theories of OCD and anxiety always focus on attention bias’ key role on development and maintenance of these symptoms. However,as an anomalous kind of anxiety disorders, the explanations for attention bias of OCD are still divided: some studies have shown that OCD patients did not show more attention bias for threat than healthy controls. Relevant researchers support that, the correlation between attention bias for threat and OCD is low, because a lot of OCD patients did not report they perceived a specific threat, in this case, their attention bias is without goals. Whereas, these studies mostly use the same or largely overlapping threat-related stimuli in patients with different types of obsessive-compulsive(OC)symptoms. In contrast, most of the studies that demonstrated attention biases in OCD have matched threat stimuli with specific types of OC concerns, because compared with other stimulus types, symptom-related stimuli may be even more to motivate attention bias of OCD individuals. Moreover, the extensive literature on attention biases forthreatening stimuli in OCD is composed mostly of studies using reaction time(RT)measures of attention(e.g., emotional Stroop task; dot probe; emotional spatial cueing task), some limitations of RT measures are inherent to using key presses as indices of attention, but these indices can not completely describe attentional components and time course of this bias.Therefore, there may have two reasons accounting for this controversial findings of attention bias in OCD: one is the diversity and heterogeneity of OC symptoms, thus, in our present studies, we select OC tendency individuals with contamination fear as the subjects, and matching the symptom-related aversive stimuli(i.e., disgusted expression and OCD-related contamination threat) for them. The other reason may be, some limitations of RT measures are inherent to using key presses as indices of attention, and thus cannot be surpassed without appealing to additional methodologies. So our studies attempt to employ eye tracking technology to carry out the experiments. Eye tracking can more immediate and continuous measure overt attention,and the relationship between eye-movements and covert attention is much closer than that of manual responses and covert attention.Given in OC tendency individuals with contamination fear, compared with fear, the relationship between threat and disgust should be much closer, so we assume:(1)compared with OC tendency individuals with low contamination fear(LOC), OC tendency individuals with high contamination fear(HOC) show the attention bias for disgust-related stimuli(disgusted face and OCD-related contamination threat images);(2)aversive bias in HOC is specific, they don’t perform any bias for fear-related stimuli(fear face and general threat images); additionally, how this attention bias embody its components and time-course is also our survey content.The purpose of our studies is to investigate attention bias(including its characteristics, components and time-course etc.)for threatening stimuli in HOC, to provide certain theoretical basis for revealing the etiological mechanism of OCD with contamination fear.In Study 1, employing free viewing task with eye tracking methodology, we select four kinds of emotional faces(disgust, fear, happy, neutral) to investigate attention bias in OC tendency individuals with contamination fear(high group of 27 people, low group of 25 people), the results showed that:(1) only for fear rather than disgusted face, HOC group’s percentage of initial fixations is significantly higher than the LOC group;(2) we don’t find any differences between groups of latency to initial fixation in the four kinds of faces;(3)HOC group’s initial gaze duration for both disgusted and fear face is significantly longer than the LOW group;(4) there has no significantly inter-groupdifferences of percentage of dwell time in four kinds of faces. Results of Study 1 show that:(1) HOC exist attention bias for disgusted face, its composition is difficulty in attention disengagement, occurring in the early stages of attention processing;(2)this bias of HOC is not specific, because they also show bias for fear face, its components include facilitated attention and difficulty in attention disengagement, and the time-course is initial attention vigilance(orienting bias) and early maintenance bias.Considering the relationship between emotional faces and contamination fear is still unclear, compared to images of contamination itself, disgusted and fear expressions as potential threat cues may be not enough to completely cause attention bias. As a result, we replaced the previous contamination cue(disgusted face), switching to use the OCD-related contamination threat, then continuing to carry out Study 2.In Study 2, employing the same method with Study 1, we select four kinds of images(OCD-related contamination threat, general threat, happy, neutral) to investigate attention bias in OC tendency individuals with contamination fear(high group of 27 people, low group of 27 people), the results showed that:(1) only for contamination threat, HOC group’s percentage of initial fixations is significantly higher than the LOC group;(2) we don’t find any differences between groups of latency to initial fixation for the four kinds of images;(3)HOC group’s initial gaze duration for contamination threat is significantly longer than the LOC group;(4)HOC’s percentage of dwell time for contamination and general threat are both significantly less than the LOC group. Results of Study 2 show that:(1) HOC exist attention bias for contamination threat, its components include facilitated attention, difficulty in attention disengagement and attentional avoidance, its time-course is initial attention vigilance(orienting bias), early maintenance bias and overall attentional avoidance at later processing stages;(2)this bias of HOC is not specific, because they also show bias for general threat, its component is attentional avoidance, occurring at later stages of attention processing.Above all, the two studies partially verify our hypothesis, namely, HOC exist attention bias for disgust stimulus, but this bias do not have specificity.