[Inconsistent motor dominance in schizophrenic patients. Evidence in favor of neurodevelopmental changes].

Introduction: Motor left lateralization preference and lateralization inconsistencies have often been reported in schizophrenia and interpreted as an expression of a neurodevelopmental deficit in this disorder. However, the reported findings are contradictory and plagued by methodological errors.

Method: The aim of this work is to examine functional motor lateralization preferences and lateralization inconsistencies in a sample on 78 schizophrenic patients by using a reliable method and comparing them with a nonclinical sample as a control group. We also study the potential associations between lateralization and several clinical, neuropsychological and neuroimage variables.

Results: No significant differences are found between schizophrenics and the control group in functional motor preferences. Other relevant finding are: absence of correlation between crural, ocular and hand preference; an association between the severity of negative symptoms and lateralization inconsistency; and an earlier clinical onset and a smaller brain volume in right-handed schizophrenics with ocular crossed lateralization as compared with right-handed schizophrenics with consistent ocular lateralization.

Conclusion: These findings back up the hypothesis of a neurodevelopmental deficit in schizophrenia.