Mirror therapy is a treatment method that uses flat-panel imaging combined with rehabilitation training programs to allow patients to observe the motion of the unaffected limbs,and to visualize and drive the motion of the limb on the affected side through optical illusion,visual feedback,and virtual reality [1].The development of mirror therapy has been widely used today in all aspects of rehabilitation programs,such as the recovery of dysfunctions,sensation,dyskinesia and language,especially the improvement of pain and exercise capacity [2-5].This review focused the mechanisms of mirror therapy,reported the possible mechanisms that may involve in the therapy.

The possible mechanisms were concluded in this review.The first one was the neurons appeared in the F5 area before the ventral movement,which also was called mirror neurons [6].In mirror therapy,the movement of the contralateral side of the limb mirror allows the patient to observe the movement of the limb in the mirror and activate the mirror neuron by imagining that the affected limb is moving,thereby replacing the proprioception to a certain extent.The input,which plays an important role in the recovery of motor cortex function.Due to the mirror neuron mechanism,the excitability of the corticospinal tract and the resulting facilitation effect can facilitate the rehabilitation of the motor function of the affected limb[7,8].At the same time,the patient's cerebellar hemisphere is also activated,which promotes the rehabilitation of limb hemiplegia.Mirror therapy can improve the presence of the affected limb through a mirrored visual illusion.Mirror therapy also can improve the presence of the affected limb through a mirrored visual illusion,which prevents the learned disuse of the affected limb.Mirror therapy also could active limbs to achieve the illusion of bilateral activities,thereby restoring motor function[9].The facilitative motor neural pathway is mainly based on the theory of interactive hemisphere inhibition.Under normal circumstances,the inhibition and promotion of bilateral brains is in a dynamic equilibrium[10].

This review also have investigated the effects of mirror therapy,which are mainly in the rehabilitation of various diseases,such as in the recovery of stroke,the relief of pain,and the improvement of cognitive dysfunction and speech dysfunction.At present,there are no evidence-based treatment protocols for mirror therapy to be used in clinical settings because of a lack of studies investigating clinical indications,treatment duration and frequency,or characteristics of mirror therapy intervention.This means that techniques are likely to vary considerably among practitioners and patients.Evidence for clinical efficacy is encouraging but not yet definitive.Nevertheless,mirror therapy is inexpensive,safe and easy for the patient to self-administer following initial training.Contraindications and side effects are few.These characteristics make mirror therapy a potential treatment option.Mirror therapy has been used in clinical practice for over two decades but it is still not widely accepted as a treatment option in our country.Through this review we hope that more clinical attention should be paid to this therapy.