Mirror movement disorder is a neurological disorder in which voluntary movements made by one side of the body are mimicked involuntarily by the other side of the body.
The mimicked movements are not of the scope of the voluntary movements, but rather smaller, less pronounced versions.
Incidence of Mirror Movement Disorder
Mirror movement disorder is considered extremely rare, and it is only typically seen in people who have wider movement disorders affecting the central nervous system crossing, such as Klippel-Feil and Kallmann syndrome, or something like Parkinson's Disease.
However, mirror movement disorder is also seen in patients who have endured a so-called cerebral insult, including those with cerebral palsy or symptomatic epilepsy, patients with a cerebrovascular accident, cranio-vertebral anomaly, and even in patients with obsessive compulsive disorder.
Recently a genetic mutation was uncovered that is believed to be the driving force in patients with mirror movement disorder but without wider movement disorders.
Neurological Foundations
The left side of the brain controls movement on the right side of the body and vice versa. This is because the 'wiring' of the nervous system is such that the nerve endings for each side of the body connect and then cross over to muscles on the other side. It is not known why this happens in humans.
In the case of mirror movement disorder, when these wires cross sides of the body they can generate movements on the same side of the body. Again, this can be the result of some wider disease of the central nervous system, or it can be a result of a genetic mutation, and as intimated above, mirror movement disorder can be the result of a so-called 'cerebral insult' such as a cerebrovascular accident, in which cases there is a reorganization of the motor cortex.
Treatments
Mirror movement disorder can cause patients to have trouble with activities in which the hands need to move independently, and it can be disruptive enough to make it hard to have control over one's other side.
Treatments are limited to some forms of physical therapy, drugs designed to limit tremors or tics in patients, and in some cases patients will benefit from adaptive technology.
