Virtual Reality Mirror Therapy, a real innovation in the management of phantom limb pain!

The "sensory" consequences of an amputation range from unpleasant sensations (tingling, pins and needles, water running over the skin, etc.) that are more or less persistent to pain (burns, stings, electric shocks, etc.).

This is called phantom limb pain(s).

Two theories confront and complement each other: "peripheral" and central. While the muscular, vascular and nervous damage seems obvious, the same cannot be said for the functioning of the brain and the cortex in particular. The cortical area (somatotopic maps) corresponding to the sensory afferents of the amputated limb interprets the absence of sensory stimuli as pain, whereas the motor efferents persist.

Sensory and motor somatotopic maps.

The pain control system is disturbed by the absence of coherent information. It is likely that the central integrating system registers discrepancies between motor intention, proprioception and/or visual representation and translates these discrepancies into a more or less clear-cut pain-like feeling.

Different pain control strategies exist and the management of phantom limb pain is more complex due to the variability of clinical presentations. Among the "classic" or known therapies, cold, heat, desensitisation, vibrations, analgesics and related products, behavioural and cognitive therapies including relaxation, hypnosis and sophrology. Complementary psychological support helps to prevent the person from focusing on their pain.

Other solutions are being studied and may be effective, such as transcranial magnetic stimulation or spinal cord stimulation in certain specific cases.

We know the cognitive and functional alternative with mirror therapy.

To understand the technique of mirror therapy: both limbs are placed on either side of a mirror and the amputated segment is hidden from view. The person observes the image of a whole limb in the mirror and has the illusion of seeing the limb move. The accompaniment of therapists (occupational therapists, physiotherapists, etc.) allows the patient to be guided in the realisation of certain movements in order to correlate their sensory and motor perceptions.

Mirror therapy is indeed based on vision, illusion, observation, imagination, motor pattern, movement and body image via central and cortical processes. And we know that the onset and management of pain involves the central nervous system. However, the brain is constantly evolving. For example, brain plasticity and/or cortical 'reorganisations' are observed when functional recoveries are observed following a stroke, even though an area of the cortex has been necroticised. In the case of stroke, the two cerebral hemispheres allow for functional redundancy that needs to be stimulated.

Mirror therapy is proving to be an effective treatment for hemiplegia, CRPS (Complex Regional Pain Syndrome or algodystrpohy) and phantom limb pain.

Case studies (Ramachandran 1993, MacLachlan 2004 & al., Chan et al. 2004, Darnall et al. 2009) have shown that mirror therapy significantly reduces phantom limb pain for sessions of 10 minutes per day.

In all of these applications, the aim is to train the brain to function differently through vision.

New technologies have opened up new perspectives for treatment with the development of three-dimensional immersive virtual reality mirror therapy.

3D immersive virtual reality allows to get rid of a sometimes difficult installation with a real or average quality mirror. Moreover, the patient is fully immersed in a controlled environment where his attention and concentration are dedicated to his rehabilitation session. Patients and users of this technology speak of effectiveness and faster achievement of therapeutic goals.

It is simply a matter of having the patient wear a virtual reality mask and being exposed to an immersive environment where they will visualise their limbs.

The virtual reality software used is therapeutic and fully adjustable in real time to suit each patient.

The effectiveness of Mirror Therapy in 3D immersive VR illusion causes a progressive pain reduction action as a "reverse learning" at the sensory level. This visual feedback of a “whole” limb reduces the discrepancy between sensations, movements, and vision, which makes it possible to reorganize and “normalize” central somatic representations.

Virtualis, a French company developing rehabilitation equipment and therapeutic software, is developing these mirror therapy solutions for the upper and lower limbs. The results can be spectacular and rapid.

This system is also used by the Laveran Military Hospital in Marseille, which takes care of amputees, and where Christophe, a patient with a left arm amputation, testifies : "It's quite surprising. It is a kind of decoy for the brain and the mind. We feel a lightness in the amputated limb. To the phantom limb" (source: Emission France 5, le magazine de la Santé du 23/09/2020 )

Therapeutic immersive virtual reality in 3 dimensions opens up new perspectives for patients and is already available in many Rehabilitation Departments, in Neurology and in private practice.

The brain is capable of therapeutic prowess if it is guided to do so. Virtualis technology can help patients control and reduce phantom limb pain.

Franz Gayet, Occupational Therapist, Virtualis Consultant/Trainer