The semantic Simon effect in Tourette's syndrome and obsessive-compulsive disorder

Core symptoms of Tourette's syndrome (TS) and obsessive-compulsive disorder (OCD) may be attributed to an impairment in inhibitory control. Neuropsychological studies have addressed inhibition in both disorders, but findings have been inconsistent. The aim of this study was to examine cognitive inhibition, using a semantic Simon effect paradigm, in patients with TS and OCD. Furthermore, to address comorbidity a group of TS+OCD patients was also examined. Results indicated that patients with TS and OCD were affected by the inhibitory components of the task. TS groups performed similarly to controls on simple and choice RT tasks, but were particularly compromised as increasingly complex inhibitory demands were imposed. OCD patients were slower and committed more errors than controls, especially in the more cognitively demanding conditions, and were particularly disadvantaged by incongruent stimulus-response compatibilities. Findings implicate possible fronto-striatal dysfunction, are consistent with previously reported inhibitory deficits in TS and OCD, and support the theory that comorbid TS+OCD is more closely linked to pure TS than OCD.     

Inhibition of Return in children with Tourette's syndrome and comorbid forms: A Preliminary Study

Background: This study investigated the nature and functioning of the visual-spatial inhibition of return (IOR) phenomenon in children with “pure” Tourette's syndrome (TS), and those with comorbid forms of TS. Method: Children with TS-only and “TS + comorbid” (TS + ADHD +/- OCD) and matched controls performed the inhibition of return (IOR) task, which involved responding to left and right visual targets appearing on a computer screen that were preceded by congruent or incongruent exogenous visual cues. Results: The TS-only group performed similarly on the IOR task to the controls. When the TS-only group was subdivided into children with mild and severe TS symptoms, a post hoc comparison between the controls and severe TS symptom children revealed that these TS children had a reduced magnitude of IOR for targets appearing in the right visual field. The comparison between the TS + comorbid and controls revealed an atypical IOR pattern for the TS + comorbid group. They displayed a loss of normal facilitatory and inhibitory effects for right visual field targets. Conclusions: The findings suggest abnormalities in attentional “disengage” and “move” mechanisms in TS when directing attention to the right visual field, which may reflect left posterior parietal, superior colliculus, and midbrain pathology.     

Inhibition of return in children with Tourette's syndrome and comorbid forms: a preliminary study.

BACKGROUND: This study investigated the nature and functioning of the visual-spatial inhibition of return (IOR) phenomenon in children with "pure" Tourette's syndrome (TS), and those with comorbid forms of TS. METHOD: Children with TS-only and "TS + comorbid" (TS + ADHD +/- OCD) and matched controls performed the inhibition of return (IOR) task, which involved responding to left and right visual targets appearing on a computer screen that were preceded by congruent or incongruent exogenous visual cues. RESULTS: The TS-only group performed similarly on the IOR task to the controls. When the TS-only group was subdivided into children with mild and severe TS symptoms, a post hoc comparison between the controls and severe TS symptom children revealed that these TS children had a reduced magnitude of IOR for targets appearing in the right visual field. The comparison between the TS + comorbid and controls revealed an atypical IOR pattern for the TS + comorbid group. They displayed a loss of normal facilitatory and inhibitory effects for right visual field targets. CONCLUSIONS: The findings suggest abnormalities in attentional "disengage" and "move" mechanisms in TS when directing attention to the right visual field, which may reflect left posterior parietal, superior colliculus, and midbrain pathology.     

Object imagery and object identification: object imagers are better at identifying spatially-filtered visual objects

Object imagery refers to the ability to construct pictorial images of objects. Individuals with high object imagery (high-OI) produce more vivid mental images than individuals with low object imagery (low-OI), and they encode and process both mental images and visual stimuli in a more global and holistic way. In the present study, we investigated whether and how level of object imagery may affect the way in which individuals identify visual objects. High-OI and low-OI participants were asked to perform a visual identification task with spatially-filtered pictures of real objects. Each picture was presented at nine levels of filtering, starting from the most blurred (level 1: only low spatial frequencies—global configuration) and gradually adding high spatial frequencies up to the complete version (level 9: global configuration plus local and internal details). Our data showed that high-OI participants identified stimuli at a lower level of filtering than participants with low-OI, indicating that they were better able than low-OI participants to identify visual objects at lower spatial frequencies. Implications of the results and future developments are discussed.     

The interaction between social saliency and perceptual saliency

The ability to select visual targets in hierarchical stimuli can be affected by both perceptual saliency and social saliency. However, the functional relations between the effects are not understood. Here we examined whether these two factors interact or combine in an additive way. Participants first learnt to associate geometric shapes with three people (e.g., triangle–self, square–stranger). After learning the associations, participants were presented with compound stimuli (e.g., a global triangle formed by a set of local squares) and had to select a target at the global or local level. In Experiment 1 the task was to identify the person associated with the local or global shape. In Experiment 2 the task was simply to identify the shape. We manipulated perceptual saliency by blurring local elements to form perceptually global salient stimuli or by contrasting the colours of neighbouring local elements (red vs. white) to form perceptually local salient stimuli. In Experiment 1 (person discrimination) there was a strong effect of saliency on local targets (there were faster and more accurate responses to high than to low saliency targets) when social and perceptual saliency occurred at same level. However, both perceptual and social saliency effects were eliminated when the effect of saliency at one level competed with that at the other level. In Experiment 2 (shape discrimination), there were only effects of perceptual saliency. The data indicate that social saliency interacts with perceptual saliency when explicit social categorizations are made, consistent with both factors modulating a common process of visual selection.     

Auditory local bias and reduced global interference in autism

Processing local elements of hierarchical patterns at a superior level and independently from an intact global influence is a well-established characteristic of autistic visual perception. However, whether this confirmed finding has an equivalent in the auditory modality is still unknown. To fill this gap, 18 autistics and 18 typical participants completed a melodic decision task where global and local level information can be congruent or incongruent. While focusing either on the global (melody) or local level (group of notes) of hierarchical auditory stimuli, participants have to decide whether the focused level is rising or falling. Autistics showed intact global processing, a superior performance when processing local elements and a reduced global-to-local interference compared to typical participants. These results are the first to demonstrate that autistic processing of auditory hierarchical stimuli closely parallels processing of visual hierarchical stimuli. When analyzing complex auditory information, autistic participants present a local bias and a more autonomous local processing, but not to the detriment of global processing.     

The role of comorbid disruptive behavior in the clinical expression of pediatric obsessive-compulsive disorder

This study explored the impact of disruptive behavior disorder (DBD) comorbidity on a number of theoretically relevant outcomes among 192 children and adolescents with obsessive-compulsive disorder (OCD). Youth were divided into three groups: OCD Only, OCD+DBD comorbidity and OCD+Other comorbidity. Relative to those without a comorbid condition and those with any non-DBD comorbidity, comorbid DBD was associated with greater family accommodation and less symptom resistance. Youth with comorbid DBD exhibited greater OCD symptom severity, OCD-related impairment, anxiety, and internalizing problems than those with no comorbidity. Those with comorbid DBD were over 3.6 times as likely to be taking an atypical antipsychotic medication relative to children without comorbidity. The present results suggest that comorbid DBD contributes to more severe illness presentation above and beyond an OCD diagnosis alone, and may be associated with differing pharmacotherapy prescribing practices.     

Obsessive-compulsive disorder patients display enhanced latent inhibition on a visual search task

Latent inhibition (LI) is a phenomenon that reflects the ability to ignore irrelevant stimuli. LI is attenuated in some schizophrenic patient groups and in high schizotypal normal participants. One study has found enhanced LI in patients with obsessive-compulsive disorder (OCD [Swerdlow, N. R., Hartston, H. J., & Hartman, P. L., 1999. Enhanced visual latent inhibition in obsessive-compulsive disorder. Biological Psychiatry, 45, 482-488]). The present experiment replicated this finding using a within-subject visual search LI task, with OCD patients displaying more LI than healthy controls. The contrasting LI effects in schizophrenia and OCD are discussed in terms of how these groups differentially process relevant and irrelevant stimuli, and how that outcome affects subsequent behavior.     

Selective attention in obsessive-compulsive disorder

Recent information-processing studies have suggested that a selective attention deficit may be involved in the symptomatology of obsessive-compulsive disorder (OCD). In this study, individuals diagnosed with OCD were distinguished from those with panic disorder and from control participants by their relatively poorer performance on a series of psychometric tasks of selective attention. These results are interpreted as supporting the hypothesis of a diminished ability of people with OCD to selectively ignore competing external (sensory) and internal (cognitive) stimuli, especially intrusive thoughts.     

Do obsessional beliefs discriminate OCD without tic patients from OCD with tic and Tourette's syndrome patients?

There is considerable overlap in symptomatology between Tourette's syndrome (TS) and obsessive-compulsive disorder (OCD). Increased rates of tics are found in OCD and up to 60% obsessive-compulsive symptoms in TS. However, in OCD obsessive-compulsive symptoms are more often anxiety-related and, as a consequence, aimed at anxiety-reduction, whereas in TS these symptoms are more stimulus-bound. Therefore, it is of clinical interest to study whether these phenomenological differences are reflected in differences between dysfunctional cognitions accompanying OC symptoms in OCD with or without tics and TS. Current cognitive theory of OCD ascertains that specific dysfunctional beliefs are important in the etiology and maintenance of OCD. To assess these beliefs, the obsessive-compulsive beliefs questionnaire-87 (OBQ-87) has been developed. In the present study, OBQ-87 scores of OCD patients without tics, OCD with tics, and TS (without OCD) patients were compared to those of normal controls. Results: OCD without tic patients exhibited higher OBQ-87 scores than TS patients. No differences were found between OCD with or without tic patients on any of the OBQ-87 subscales. These results suggest that: (1) dysfunctional beliefs have no discriminative power with respect to OCD with or without tic patients; (2) the direct relationship between types of OC symptoms and specific dysfunctional beliefs is questionable. Therefore, one can doubt the specificity of cognitive theory of OCD to explain specific OC behavior.     

Global precedence effect in audition and vision: evidence for similar cognitive styles across modalities

This study aimed to provide evidence for a Global Precedence Effect (GPE) in both vision and audition modalities. In order to parallel Navon's paradigm, a novel auditory task was designed in which hierarchical auditory stimuli were used to involve local and global processing. Participants were asked to process auditory and visual hierarchical patterns at the local or global level. In both modalities, a global-over-local advantage and a global interference on local processing were found. The other compelling result is a significant correlation between these effects across modalities. Evidence that the same participants exhibit similar processing style across modalities strongly supports the idea of a cognitive style to process information and common processing principle in perception.     

Obsessive-compulsive disorder with comorbid major depression: what is the role of cognitive factors?

Individuals with obsessive-compulsive disorder (OCD) commonly experience comorbid mood disturbances such as major depressive disorder (MDD). Previous studies that have compared OCD patients with and without MDD have revealed differences in demographic characteristics, clinical severity, and symptom presentation between these two patient groups. Previous studies have not, however, examined whether there are differences with respect to cognitive processes. The present study therefore aimed to address this gap in the literature. Eighty patients with OCD and no unipolar mood disorders were compared with 34 OCD patients with comorbid major depression on measures of OCD symptoms, cognitions, and insight, as well as on measures of depression and functional impairment. Whereas depressed OCD patients evidenced higher scores than non-depressed OCD patients on semi-idiographic measures of OCD symptoms and cognitions, this was not the case for nomothetic measures. Functional impairment and the tendency to misinterpret innocuous intrusive thoughts as significant emerged as unique predictors of depression within the entire sample of OCD patients. Results are discussed in terms of (a) the importance of semi-idiographic assessment of OCD, (b) possible explanations for the relationship between OCD symptoms, depression, and cognitive processes, and (c) the psychological treatment of comorbid OCD and MDD.     

Global precedence and response activation: Evidence from LRPs

Lateralized readiness potentials (LRPs) were measured in left/right/no-go tasks using compound global/local stimuli. In Experiment 1, participants responded to local target shapes and ignored global ones. RTs were affected by the congruence of the global shape with the local one, and LRPs indicated that irrelevant global shapes activated the responses with which they were associated. In Experiment 2, participants responded to conjunctions of target shapes at both levels, withholding the response if a target appeared at only one level. Global shapes activated responses in no-go trials, but local shapes did not. The results are consistent with partial-output models in which preliminary information about global shape can partially activate responses that are inconsistent with the local shape. They also demonstrate that part of the global advantage arises early, before response activation begins and probably before recognition of the local shape.     

Gender differences in global-local perception? Evidence from orientation and shape judgments

Direct examinations of gender differences in global-local processing are sparse, and the results are inconsistent. We examined this issue with a visuospatial judgment task and with a shape judgment task. Women and men were presented with hierarchical stimuli that varied in closure (open or closed shape) or in line orientation (oblique or horizontal/vertical) at the global or local level. The task was to classify the stimuli on the basis of the variation at the global level (global classification) or at the local level (local classification). Women’s classification by closure (global or local) was more accurate than men’s for stimuli that varied in closure on both levels, suggesting a female advantage in discriminating shape properties. No gender differences were observed in global-local processing bias. Women and men exhibited a global advantage, and they did not differ in their speed of global or local classification, with only one exception. Women were slower than men in local classification by orientation when the to-be-classified lines were embedded in a global line with a different orientation. This finding suggests that women are more distracted than men by misleading global oriented context when performing local orientation judgments, perhaps because women and men differ in their ability to use cognitive schemes to compensate for the distracting effects of the global context. Our findings further suggest that whether or not gender differences arise depends not only on the nature of the visual task but also on the visual context.     

Sequential priming in hierarchically organized figures: effects of target level and target resolution.

Three experiments are reported in which participants identified target letters that appeared at either the global or local level of hierarchically organized stimuli. It has been previously reported that response time is facilitated when targets on successive trials appear at the same level (L. M. Ward, 1982; L. C. Robertson, 1996). Experiments 1 and 2 showed that this sequential priming effect can be mediated by target-level information alone, independent of the resolution, or actual physical size, of targets. Target level and resolution were unconfounded by manipulating total stimulus size, such that global elements of the smaller stimuli subtended the same amount of visual angle as local elements of the larger stimuli. Experiment 3, however, showed that when level information is less useful than resolution in parsing targets from distractors, resolution does become critical in intertrial priming. These data are discussed as they relate to the role of attention in local vs. global (part vs. whole) processing.     

The effects of local and global processing demands on perception and action

The line-bisection task, adapted to utilise a wooden rod as the bisection stimulus, has revealed that patients with visuo-spatial neglect may be more accurate at bisection when asked to pick up the rod, compared to pointing to its centre. We recently reported that neurologically intact participants show a similar dissociation on this task-demonstrating a rightward bias when pointing to the centre, which was not present when grasping the rod by the centre. The current paper examined how pointing and grasping responses were affected by adapted rod-bisection tasks that emphasised local or global processing. In Experiment 1, 26 participants completed four rod-bisection tasks. The rods were compound stimuli and the participants directed to focus on either the local or global level. The results demonstrated that when participants focused on the global level, the previous dissociations found for pointing and grasping conditions were evident. However, the perception of centre did change when participants focused on the local level: both the pointing and grasping responses were rightward biased. In Experiment 2, 42 participants completed three bisection tasks which again emphasised either the local or global level, but in different sets of stimuli. The results of this task further support the findings in Experiment 1: the rightward bias in the local-bisection task was again evident and in addition, the global-bisection task resulted in no bias and no difference between the pointing and grasping bisections. These results demonstrate how task demands can similarly affect the pointing and grasping responses, and indicate that local and global processing may be involved in perception/action dissociations on rod bisection.     

Same,same — but different: On the use of Navon derived measures of global/local processing in studies of face processing

Some studies have reported a significant correlation between face discrimination/recognition ability and indexes of global/local processing derived from the Navon paradigm. Other studies, however, have failed to find such a relationship. In this paper we examine three aspects related to the Navon paradigm that may have contributed to this discrepancy but which have been largely neglected: (i) the use of different types of compound stimuli across studies, (ii) differences between studies in the type of index derived from the Navon paradigm, and (iii) the reliability of these indexes. In a Navon experiment comparing performance with compound letters and compound shapes in normal participants, we find little consistency both within and across participants in how they perform with these stimulus types, despite the fact that both stimulus types give rise to the typical effects. In addition we find that many of the Navon derived indexes of global/local effects used in studies examining face processing have low reliability and do not measure the same aspects of global/local processing. Echoing the results from the normal participants, we also find little consistency in how a congenital prosopagnosic performs in the Navon paradigm. With compound letters, she responds much faster to local than to global aspects of the stimuli; a pattern not seen in a single of the normal participants. With compound shapes, however, she exhibits no such abnormality. These findings question the validity of the conclusions in studies relating Navon derived indexes of global/local processing to face processing.     

Effects of the global and local attention on the processing of categorical and coordinate spatial relations

Participants made categorical or coordinate spatial judgments on the global or local elements of shapes. Stimuli were composed of a horizontal line and two dots. In the Categorical task, participants judged whether the line was above or below the dots. In the Coordinate task, they judged whether the line would fit between the dots. Stimuli were made hierarchical so that the global patterns composed of a “global line” made of local dots-and-line units, and “global dot” made of a single dots-and-line unit. The results indicated that the categorical task was better performed when participants attended to the local level of the hierarchical stimuli. On the other hand, the coordinate task was better performed when they attended to the global level. These findings are consistent with computer simulation models of the attentional modulation of neuronal receptive fields’ size suggesting that (1) coordinate spatial relations are more efficiently encoded when one attends to a relatively large region of space, whereas (2) categorical spatial relations are more efficiently encoded when one attends to a relatively small region of space.     

Attention bias for social threat in youth with tic disorders: Links with tic severity and social anxiety

Many individuals with Tourette syndrome and chronic tic disorders (TS/CTDs) report poor social functioning and comorbid social anxiety. Yet limited research has investigated the role of cognitive factors that highlight social threats in youth with TS/CTD, and whether these biases underlie tic severity and co-occurring social anxiety. This study examined whether selective attention to social threat is enhanced young people with TS/CTDs compared to healthy controls, and whether attention biases are associated with tic severity and social anxiety. Twenty seven young people with TS/CTDs and 25 matched control participants completed an experimental measure of attention bias toward/away from threat stimuli. A clinician-rated interview measuring tic severity/impairment (YGTSS Total Score) and questionnaire measures of social anxiety were completed by participants and their parents. Young people with TS/CTD showed an attention bias to social threat words (relative to benign words) compared to controls but no such bias for social threat faces. Attention bias for social threat words was associated with increasing YGTSS Total Score and parent-reported social anxiety in the TS/CTDs group. Mediation analysis revealed a significant indirect path between YGTSS Total Score and social anxiety, via attention to social threat. Tentatively, these associations appeared to be driven by impairment rather than tic severity scores. Preliminary data suggests that youth with TS/CTD have enhanced attention to threat, compared to controls, and this is associated with impairment and social anxiety. Attention to threat could offer a cognitive mechanism connecting impairment and social anxiety, and so be a valuable trans-diagnostic treatment target.     

Attenuated Access to Emotions in Obsessive-Compulsive Disorder

The Seeking Proxies for Internal States (SPIS) model of obsessive-compulsive disorder (OCD) posits that OCD is associated with attenuated access to internal states. Here we explored the implications of this model in the realm of emotions. Participants with OCD, anxiety disorders, and nonclinical control participants completed the Mayer-Salovey-Caruso Emotional Intelligence Test (MSCEIT), assessing two domains of emotional intelligence: Experiential emotional intelligence (EI), reflecting the ability to perceive and feel emotions accurately, and Strategic EI, reflecting the ability to understand and manage emotions correctly. As only Experiential EI requires accurate perception of one’s emotions for adequate performance, we predicted an interaction between group and EI area. Specifically, we predicted that compared to both anxiety disorders and healthy control participants, OCD participants would show a larger deficit in Experiential area of the MSCEIT relative to the Strategic area. Results were fully in line with this prediction. Moreover, supporting the specificity of the hypothesized deficit to OCD, participants with anxiety disorders did not differ from nonclinical control participants in their performance, and findings were not attributable to anxiety or depression levels. These results replicate and extend previous findings obtained with analogue samples and suggest that OCD is associated with attenuated access to emotional states, which may be partially compensated for by reliance on semantic knowledge of emotion.