Virtual images as a perceptual orthosis to assist Parkinson´s disease gait disorders

The purpose of this research was to demonstrate the effectiveness of non-tangible objects provided as virtual images to evoke the phenomenon called kinesia paradoxa in Parkinson´s patients. The virtual objects were projected on the visual field of the subject by means of an augmented reality head mounted display in order to superimpose real and artificial environments. The results confirm that the temporary improvement of gait in Parkinson´s disease (PD) depends on the merging of two factors: the provision a fixed visual reference that triggers the initiation of motion, and sustained ambulation by means of a pace-making, dynamic stimulus. Gait parameters were measured in 20 subjects with PD of stages III and IV of the Hoen-Yarh scale before, during and after the visual stimulation in order to demonstrate an immediate effect on gait. A short-term, carry-over effect was also found