Pseudoneglect in schizophrenia: a line bisection study with cueing.

Introduction: Numerous authors have reported the existence of lateralised abnormalities towards the right side in patients with schizophrenia.

Methods: In the present study, a manual line bisection task was used to assess the existence of a visuospatial bias in patients with schizophrenia as compared to healthy subjects and left unilateral neglect patients. In addition, we used a local cueing paradigm (consisting of a number placed on the right, on the left, or at both ends of the line).

Results: Healthy subjects showed a leftwards trend in the "no cue" condition (known as pseudoneglect) and neglect patients showed a right bias in all cue conditions. In contrast, patients with schizophrenia placed their manual estimation of the centre further to the left than healthy subjects in all cue conditions, reflecting neglect of the right side of the line. Moreover, like healthy subjects and neglect patients, patients with schizophrenia were affected by the local cueing.

Conclusion: Hence, patients with schizophrenia show a bias in their spatial representation, which does not interfere with local context processing.