A rehabilitation therapy aid (FIG. 4), for use in aiding a patient to regain and improve movement and control in a limb, comprises a moveable structure (51) having engagement means (53) whereby the structure can be moved by the limb of a patient (72) requiring therapy and separate engagement means (52) whereby the structure can be moved in the same direction by a therapist (71) or by the patient's stronger limb. A movement detector (56) is arranged so that the movement of the structure (51) can be tracked by the patient and/or by the therapist.