Effect of dual tasking on postural control in individuals with schizophrenia

Objective: To investigate the effect of dual tasking on postural control in individuals with schizophrenia. Methods: Fifteen outpatients with schizophrenia and 15 healthy controls were included. Postural control was assessed with postural sway velocity (PSV) using Balance Master System during three different tasks: single task (standing on a force platform), cognitive task (categorical verbal fluency) and motor task (holding a cup of water) in four conditions: on firm surface with eyes open (1) and closed (2), on foam surface with eyes open (3) and closed (4). Results: Individuals with schizophrenia presented higher PSV during single standing on foam surface with eyes open and closed. During the cognitive task, they showed higher PSV on foam surface with eyes closed. During the motor task PSV in schizophrenia group was higher on firm surface with eyes closed and on foam surface with eyes open and closed. Individuals with schizophrenia showed higher PSV during cognitive task on firm surface with eyes closed compared to the single task. Conclusions: Dual tasking results in a deterioration in postural control in individuals with schizophrenia. A cognitive task specifically alters postural control in the absence of visual information suggesting a possible sensorimotor dysfunction in this population.