Attention diversion and Gestural Rehabilitation with Virtual Reality
Mirror therapy and modulation of the visual perception of the size of a painful limb has an effect on the intensity of the pain perceived by the patient. Thus, vision is part of the pain. What happens if the visual perception of the size of a painful limb is reduced to such an extent that it is no longer visible to the patient?
The total removal of the visualization of a limb in a virtual environment removes the patient's visual input on segmental positioning in space. Sight will no longer be able to serve as a positional reference in anticipatory reactions to the perception of pain during movement. The patient will have to prioritise his deep or superficial somaesthetic inputs over the visual input.
VR is thus an indispensable tool for initiating movement rehabilitation in the context of kinesiophobia. The performance of a task by the patient without visual perception of the movements of a limb allows a reduction in the anticipated amplitude limitation to get closer to a real anatomical limitation. The practitioner makes the patient perform a gesture or a movement in VR in a non-painful area. During its execution, he/she can modulate the task or the environment in real time to get closer to and then exceed the amplitude anticipated as painful.
These modifications may or may not be perceptible to the patient. When performing a task in the first person, the patient makes his avatar perform a virtual task on the same scale as his real gesture. The patient's sensations of amplitude are thus superimposed on the gesture. In a third-person environment, the patient interacts with an object indirectly. The practitioner can vary the sensitivity of the parameters requiring the patient to increase his gestural amplitude without him being able to visually perceive a change in his environment, dissociating sight in order to promote gestural perception.
The diversion of attention by VR also has its place in cases of muscular sideration. The variations of parameters in the virtual environment refocus the patient's attention on a gestural achievement and not on a local lesion focus. In doing so, the practitioner can look for a muscle contraction by chain diffusion or by direct contraction.
Virtual reality is a multi-sensory stimulation tool that addresses many clinical symptoms and continues to evolve to meet the needs of patients. The real-time adaptability of environments and tasks to be performed by the patient is justified as an essential criterion by many publications.
 From motor control to gesture organisation. J. Paillard and D. Beaubaton Paris, Masson, 1978, 225-260.