J Psychiatry Neurosci 2013; 38(5): 317-324
Céline Delerue, PhD; Mary Hayhoe, PhD; Muriel Boucart, PhD
Delerue, Boucart — Laboratoire de Neurosciences Fonctionnelles et Pathologies, Université Lille — Nord de France, CNRS, Lille, France; Hayhoe — Center for Perceptual Systems, University of Texas, Austin, Tex., USA
Background: Visual scanning and planning of actions are reported to be abnormal in patients with schizophrenia. Most studies that monitored eye movements in these patients were performed under free-viewing conditions and used 2- dimensional images. However, images differ from the natural world in several ways, including task demands and the dimensionality of the display. Our study was designed to assess whether abnormalities in visual exploration in patients with schizophrenia generalize to active-viewing tasks in realistic conditions of viewing and to examine whether disturbances in action sequencing in these patients are reflected in their visual scanning patterns while executing natural tasks.
Methods: We monitored visual scan paths in patients with schizophrenia and healthy controls. Participants performed several tasks in which they were asked to look at a realistic scene on a table (free-viewing) and perform 2 active-viewing tasks: a familiar task (sandwich-making) and an unfamiliar task (model-building). The scenes contained both task-relevant and task-irrelevant objects.
Results: We included 15 patients and 15 controls in our analysis. Patients exhibited abnormalities in the free-viewing condition. Their patterns of exploration were similar to those of controls in the familiar task, but they showed scanning differences in the unfamiliar task. Patients were also slower than controls to accomplish both tasks.
Limitations: Patients with schizophrenia were taking antipsychotic medications, so the presence of medication effects cannot be excluded.
Conclusion: People with schizophrenia present a basic psychomotor slowing and seem to establish a less efficient planning strategy in the case of more complex and unfamiliar tasks.
Submitted July 25, 2012; Revised Dec. 6, 2012, Feb. 3, 2013; Accepted Feb. 5, 2013.
Acknowledgements: The authors are grateful to all of the patients who accepted to take part in the study and the psychiatrists who gave access to their patients and their staff. The study was funded by a PhD grant to C. Delerue by the region Nord-Pas de Calais and the Lille University Hospital. M. Hayhoe’s participation was supported by National Institutes of Health grant EY-05729.
Competing interests: As above for C. Delerue and M. Hayhoe. Otherwise, none declared.
Contributors: C. Delerue and M. Boucart designed the study. C. Delerue acquired the data. All authors analyzed the data, wrote and reviewed the article, and approved its publication.
Correspondence to: C. Delerue, CHU Lille, Hôpital Roger Salengro, Laboratoire de Neurosciences Fonctionnelles et Pathologies, F-59037
Lille, France; email@example.com