Visuospatial encoding deficits and compensatory strategies in schizophrenia revealed by eye movement analysis during a working memory task

Charting the Diversity of Strategic Processes in Visuospatial Short-Term Memory

Despite the abundant literature on visuospatial short-term memory, researchers have devoted little attention to strategic processes: What procedures do subjects implement to memorize visuospatial material? Evidence for various strategies exists, but it is spread across a variety of fields. This integrative review of the literature brings together scattered evidence to provide an overview of strategic processes in visuospatial memory tasks. The diversity of strategies and their proposed operating mechanisms are reviewed and discussed. The evidence leads to proposing seven broad strategic processes used in visuospatial short-term memory, each with multiple variants. Strategies can vary across individuals, but the same subjects also appear to use multiple strategies depending on the perceptual features of to-be-remembered displays. These results point to a view of visuospatial strategies as a functional library of facilitatory processes on which subjects can draw to support visuospatial short-term memory performance. Implications are discussed for the difference between visual and spatial tasks, for the appropriate measurement of strategic behaviors, and for the interpretation of performance in visuospatial memory tasks.

Comparison of Visuospatial and Verbal Abilities in First Psychotic Episode of Schizophrenia Spectrum Disorder: Impact on Global Functioning and Quality of Life

Objectives: Deficit in visuospatial functions can influence both simple and complex daily life activities. Despite the fact that visuospatial deficit was reported in schizophrenia, research on visuospatial functions as an independent entity is limited. Our study aims to elucidate the impact of visuospatial deficit in comparison with verbal deficit on global functioning and quality of life in the first psychotic episode of schizophrenia spectrum disorder (FES). The significance of clinical symptoms and antipsychotic medication was also studied.

Methods: Thirty-six FES patients and a matched group of healthy controls (HC group) were assessed with a neuropsychological battery focused on visuospatial (VIS) and verbal (VERB) functions. Using multiple regression analysis, we evaluated the cumulative effect of VERB and VIS functions, psychiatric symptoms (PANSS) and antipsychotic medication on global functioning (GAF) and quality of life (WHOQOL-BREF) in the FES group.

Results: The FES group demonstrated significant impairment both in VIS and VERB cognitive abilities compared to the HC group. Antipsychotic medication did not significantly affect either VIS or VERB functioning. PANSS was not related to cognitive functioning, apart from the Trail Making Test B. In the FES group, the GAF score was significantly affected by the severity of positive symptoms and VERB functioning, explaining together 60% of GAF variability. The severity of negative and positive symptoms affected only the Physical health domain of WHOQOL-BREF. The degree of VERB deficit was associated with both Physical and Psychological health. Although we did not find any relation between VIS functioning, GAF, and WHOQOL-BREF, a paradoxical finding emerged in the Environment quality domain, where a worse quality of the environment was associated with better VIS functioning.

Conclusions: Our results suggest that the deficit in VIS functions is an integral part of cognitive deficit in schizophrenia spectrum disorders, rather than a side effect of symptomatology or antipsychotic medication. Moreover, VERB functioning was a better predictor of GAF and WHOQOL-BREF than VIS functioning. Given the findings of negative or missing effect of VIS deficit on WHOQOL-BREF and GAF, the accuracy of these measures in evaluating the impact of global cognitive deficit on everyday life in schizophrenia could be questioned.

Vision, spatial cognition and intellectual disability

Vision is the most synthetic sensory channel and it provides specific information about the relative position of distant landmarks during visual exploration. In this paper we propose that visual exploration, as assessed by the recording of eye movements, offers an original method to analyze spatial cognition and to reveal alternative adaptation strategies in people with intellectual disabilities (ID). Our general assumption is that eye movement exploration may simultaneously reveal whether, why, and how, compensatory strategies point to specific difficulties related to neurological symptoms. An understanding of these strategies will also help in the development of optimal rehabilitation procedures.

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.

Visual scanning of emotional faces in schizophrenia

This study investigated eye movement differences during facial emotion recognition between 101 patients with chronic schizophrenia and 101 controls. Independent of facial emotion, patients with schizophrenia processed facial information inefficiently; they showed significantly more direct fixations that lasted longer to interest areas (IAs), such as the eyes, nose, mouth, and nasion. The total fixation number, mean fixation duration, and total fixation duration were significantly increased in schizophrenia. Additionally, the number of fixations per second to IAs (IA fixation number/s) was significantly lower in schizophrenia. However, no differences were found between the two groups in the proportion of number of fixations to IAs or total fixation number (IA fixation number %). Interestingly, the negative symptoms of patients with schizophrenia negatively correlated with IA fixation number %. Both groups showed significantly greater attention to positive faces. Compared to controls, patients with schizophrenia exhibited significantly more fixations directed to IAs, a higher total fixation number, and lower IA fixation number/s for negative faces. These results indicate that facial processing efficiency is significantly decreased in schizophrenia, but no difference was observed in processing strategy. Patients with schizophrenia may have special deficits in processing negative faces, and negative symptoms may affect visual scanning parameters.

Obstetric complications and neurological soft signs in male patients with schizophrenia

Bersani G, Clemente R, Gherardelli S, Bersani FS, Manuali G. Obstetric complications and neurological soft signs in male patients with schizophrenia.

Objective: The study investigated the relationship between neurological soft signs (NSS) and obstetric complications (OCs) in patients with schizophrenia.

Methods: Sixty-three male patients with schizophrenia were divided into two subgroups, based on the OCs presence or absence, which were compared in relation to NSS prevalence. After that, a Person's correlation test was performed to explore the correlation between NSS and OCs severity.

Results: The subgroup with OCs showed more NSS, but there were not significant correlations between NSS and OCs severity.

Conclusions: It seems that any OC, without distinction in typology and severity, could unspecifically impair the neurodevelopment and inducing NSS expression. Our findings confirm the hypothesis that neurodevelopment alterations, such as those probably induced by OCs, can contribute to a premorbid brain dysfunctional state expressed by NSS.

Current visual scanpath research: a review of investigations into the psychotic, anxiety, and mood disorders

The human visual system is comprised of an array of complex organs, which jointly decode information from visible light to construct a meaningful representation of the surrounding environment. The study of visual scanpaths transpired in a bid to enhance our understanding of the role of eye movements underpinning adaptive functioning as well as psychopathology and was further aided by the advent of modern eye-tracking techniques. This review provides a background to the nature of visual scanpaths, followed by an overview and critique of eye movement studies in specific clinical populations involving the psychotic, anxiety, and mood disorders, and concludes with suggested directions for future research. We performed a Medline and PsycInfo literature search, based on variations of the terms "visual scanpath," "eye-tracking," and "eye movements," in relation to articles published from 1986 to the present. Eye-tracking studies in schizophrenia mostly concurred with the existence of a "restricted" scanning strategy, characterized by fewer number of fixations of increased durations, with shorter scanpath lengths, and a marked avoidance of salient features, especially in relation to facial emotion perception. This has been interpreted as likely reflecting dual impairments in configural processing as well as gestalt perception. Findings from the anxiety and mood disorders have conversely failed to yield coherent results, with further research warranted to provide corroborating evidence and overcome identified methodological limitations. Future studies should also look toward applying similar techniques to related disorders as well as conducting parallel neuroimaging investigations to elucidate potential neurobiological correlates.