A mirror box is a device used with patients who experience phantom limb pain, paralysis, and neuropathic pain. Patients insert both limbs, commonly the arms, into the box, covering the injured limb. They watch the movements of the healthy limb in the mirror to repattern their brains. This may be offered as part of a therapy program, and can be performed at home as well as under the direction of a skilled medical professional. Research on the use of mirror box therapy shows it can be beneficial for some patients.
The idea behind mirror box therapy is that as people attempt to move injured limbs, the remaining nerves send signals to the brain; in the case of a paralyzed limb, these signals might be a reminder that the limb cannot move. For amputations, the nerves may expression confusion because there is no limb there. Over time, these signals may devolve into messages about pain, creating phantom pain and irritation. If the patient has some function in the limb, these signals may limit range of motion because the patient starts to fear the pain.
Tactics like physical therapy as well as medication can help alleviate pain and increase range of motion. The mirror box can be used as a tool to retrain the brain so that it stops processing nerve signals erroneously. It can be used with the arms or legs. Patients typically start working with a health care provider, who has them insert both limbs into the box, and adds a cover to the side of the box with the injured limb.
A mirror in the middle of the box flips the healthy limb, creating a mirror image. The patient can perform a series of exercises, watching the mirror image, which creates the illusion that the injured or missing limb is fully engaged. These exercises can vary in nature and complexity. This can essentially trick the brain into believing it has two healthy limbs, which reroutes the patterns previously established by pain signals.
Patients who use a mirror box may experience a decrease in phantom limb pain. Others may experience pain because of neurological injuries or other problems, and might find the box successful as a noninvasive method of pain management. Pain associated with paralysis may be alleviated, and patients with poor coordination could experience an improvement after mirror box therapy sessions. The technique is not effective with all patients, but may be considered or presented as an option if therapists think it might be useful.