Excessive checking behavior during an image comparison task in schizophrenia.

BACKGROUND: Patients with schizophrenia display significant working memory and executive deficits. In patients with obsessive-compulsive disorder (OCD), several studies suggest that working memory dysfunction may be one of the causes of compulsive checking behaviors. Hence, this study aimed at assessing whether patients with schizophrenia were impaired on an image comparison task used to measure checking behaviors, and whether the origin and profile of impairment on this task was different between schizophrenia and OCD. METHODS: Eye movement recordings were used to assess the checking behavior of 24 patients with schizophrenia and 24 control participants who had to decide whether two images were different or identical. The verbal and visuo-spatial components of participants' working memory were measured using the reading span and backward location span tests. RESULTS: Compared to controls, patients with schizophrenia had reduced working memory spans and showed excessive checking behavior when comparing the two images. However, the intensity of their checking behavior was not significantly related to their working memory deficits. CONCLUSIONS: Several recent studies demonstrated that the excessive checking behaviors displayed by patients with OCD were related to working memory dysfunction. The absence of a relationship between the excessive checking behavior of patients with schizophrenia and their working memory deficits suggests that checking behaviors do not have the same origin in the two disorders.

Forgetting what you have checked: a link between working memory impairment and checking behaviors in obsessive-compulsive disorder.

BACKGROUND: Compulsive checking behaviors are common in obsessive-compulsive disorder (OCD). Several authors have suggested that these checking rituals could be related to memory deficits. Our aim was to test whether patients with OCD show working memory impairment in relation to their checking behavior. METHODS: We evaluated the verbal and visuospatial components of patients' and controls' working memory using the reading span and backward location span tests. Checking behaviors were measured by recording participants' eye movements during an image comparison task using a non-invasive, infra-red TOBII 1750 eyetracker. Participants were seated, head-free, in a natural position in front of the eyetracker screen where the images were displayed. RESULTS: Patients with OCD made more gaze moves to compare images than controls. Both patients' working memory spans were reduced, and the patients' deficit in the comparison task was negatively related to their working memory spans. CONCLUSIONS: This work demonstrates that checking behavior in OCD is linked to a general reduction of the patients' verbal and visuospatial working memory span.

A critical review of the contribution of eye movement recordings to the neuropsychology of obsessive compulsive disorder.

OBJECTIVE: Dysfunctions of saccadic and/or smooth pursuit eye movements have been proposed as markers of obsessive compulsive disorder (OCD), but experimental results are inconsistent. The aim of this paper was to review the literature on eye movement dysfunctions in OCD to assess whether or not saccades or smooth pursuit may be used to diagnose and characterize OCD. METHOD: Literature was searched using PubMed, ISI Web of Knowledge, and PsycINFO databases for all studies reporting eye movements in adult patients suffering from OCD. RESULTS: Thirty-three articles were found. As expected, eye movements of the patients with OCD were mostly assessed with simple oculomotor paradigms involving saccadic and/or smooth pursuit control. In contrast to patients with schizophrenia, however, patients with OCD only displayed rather unspecific deficits, namely slight smooth pursuit impairments and longer response latencies on antisaccade tasks. There was no relationship between these deficits and the severity of patients' symptoms. Interestingly, eye movements of the patients with OCD were almost never recorded during more complex cognitive tasks. CONCLUSION: As in schizophrenia and autism, eye movement recordings during more complex tasks might help to better characterize the cognitive deficits associated with OCD. Such recordings may reveal specific OCD-related deficits that could be used as reliable diagnostic and/or classification tools.

Effects of gender marking in pronominal coindexation.

The naming latency of a pronoun was measured when a single previously presented name in a discourse either agreed or did not agree with the pronoun in gender and person. An effect of agreement was found both under conditions in which subjects were likely to have engaged in strategic processing of the pronoun (Experiment 1) and under conditions in which this was unlikely (Experiment 3). The effect of gender agreement was also investigated when two noun phrases were present in the discourse. The results continued to show an immediate effect of gender agreement (naming latencies increased when a pronoun did not agree with one of two previously presented nouns) under experimental conditions likely to engender strategic processing (Experiment 2). This last effect was not significant under experimental conditions that were not likely to engender strategic processing (Experiment 3). The results are discussed in terms of models of the process of identifying the referent of a pronoun in a discourse.