Introduction: Contrary to the belief that postural control is quite automatic, researches have shown the attentional demand of postural control. Most of stroke patients have deficits in sensory, motion and cognitive systems. Therefore, the purpose of this study was to investigate the effects of working memory Dual Task on postural sways in chronic stroke patients. Materials and Methods: Twenty subjects diagnosed with chronic stroke participated in the study. Center of pressure (COP) fluctuations parameters including mean standard deviation and mean velocity of changes in both medial–lateral (ML) and anterior–posterior (A.P) directions were randomly measured during quiet standing on a force plate for 30 s in three different conditions: base line standing, standing while phonological loop component of working memory was activated, and standing while visuospatial sketchpad component of working memory was activated. Participants performed 3 trials in which they had completed working memory task correctly in each condition. Repeated measure ANOVA was used to analyze the COP parameters. Results: results indicate that the effects of Interference on postural sway were only exhibited in mean of velocity in ML direction (p<0.05). There was not significant difference between conditions in the AP direction. Visuospatial working memory task led to greater Interference in postural sways in comparison to phonological loop working memory task (p>0.05). Discussion: Visuospatial working memory dual task adversely affect ML postural sways in stroke patients and let to reduced postural control, hence interfered more with postural control of stroke people in comparison to phonological loop working memory. It seems that there are common neural circuit for postural control and visuospatial processing. This might result from reduced asymmetric weight distribution with Visuospatial working memory task. The results suggest that effective rehabilitative and therapeutic strategies should take into consideration the possible use of specific working memory dual task protocols for stroke patients.

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