Effects of Practice, Visual Loss, Limb Amputation, and Disuse on Motor Imagery Vividness

Background. The ability to generate vivid images of movements is variable across individuals and likely influenced by sensorimotor inputs. Objectives. The authors examined (1) the vividness of motor imagery in dancers and in persons with late blindness, with amputation or an immobilization of one lower limb; (2) the effects of prosthesis use on motor imagery; and (3) the temporal characteristics of motor imagery. Methods. Eleven dancers, 10 persons with late blindness, 14 with amputation, 6 with immobilization, and 2 groups of age-matched healthy individuals (27 in control group A; 35 in control group B) participated. The Kinesthetic and Visual Imagery Questionnaire served to assess motor imagery vividness. Temporal characteristics were assessed with mental chronometry. Results. The late blindness group and dance group displayed higher imagery scores than respective control groups. In the amputation and immobilization groups, imagery scores were lower on the affected side than the intact side and specifically for imagined foot movements. Imagery scores of the affected limb positively correlated with the time since walking with prosthesis. Movement times during imagination and execution (amputation and immobilization) were longer on the affected side than the intact side, but the temporal congruence between real and imagined movement times was similar to that in the control group. Conclusions. The mental representation of actions is highly modulated by imagery practice and motor activities. The ability to generate vivid images of movements can be specifically weakened by limb loss or disuse, but lack of movement does not affect the temporal characteristics of motor imagery.