Redundancy of the motor control system is an important feature that gi
ves the central control structures options for solving everyday motor
problems. The choice of particular control patterns is based on priori
ties (coordinative rules) that are presently unknown. Motor patterns o
bserved in unimpaired young adults reflect these priorities. We hypoth
esize that under certain atypical conditions, which may include disord
ers in perception of the environment and in decision making, structura
l or biochemical changes within the central nervous system (CNS), and/
or structural changes of the effectors, the central nervous system may
reconsider its priorities. A new set of priorities will reflect the c
urrent state of the system and may lead to different patterns of volun
tary movement. Under such conditions, changed motor patterns should be
considered not pathological but rather adaptive to a primary disorder
and may even be viewed as optimal for a given state of the system of
movement production. Therapeutic approaches should not be directed tow
ard restoring the motor patterns to as close to ''normal'' as possible
but rather toward resolving the original underlying problem. We illus
trate this approach using, as examples, movements in amputees, in pati
ents with Parkinson's disease, in patients with dystonia, and in perso
ns with Down syndrome.