One of the causes of disability in patients suffering from a stroke is postural imbalance. Sensory stimulation improves the postural symmetry of the subject transitorily and they are thought to have an effect on the spatial frame of reference through a sensory recalibration. Studies have shown that sensory stimulation by vibration of neck muscles have an immediate effect on static balance and when walking. The objective of this preliminary study is to test the long-lasting effects of repetitive neck muscle vibrations on postural disturbances in standing position and on spatial frame reference in chronic patients.