Also known as motor sensation and illusory movement. The term motor illusion is indebted to the Latin noun motio, which means movement. It is used to denote a * kinaesthetic hallucination characterized by the illusory sensation of movement of one or more body parts. Pathophysio-logically, motor illusions are associated primarily with lesions of parts of the parietal lobe involved with bodily representation and/or the representation of movement. Etiologically, they are associated primarily with * aurae occurring in the context of paroxysmal neurological disorders such as migraine and epilepsy. Motor illusions may also occur in individuals with a clinical diagnosis of * schizophrenia or in the context of hemiplegia due to parietal lobe lesions. As the British neurologist Macdonald Critchley (1900-1997) maintains, "The patient may entertain that one of his limbs is completely detached from his own body and occupies some position nearby or afar. Or the patient may imagine his affected limb to be moving when it is actually immobile. Such an idea may be illusory or delusional; it can occur in episodic fashion, or it can be continual." As demonstrated in myriad experimental configurations, motor illusions can be evoked within seconds when muscle vibration is used to generate proprioceptive misinformation about limb position. Some examples of the resulting motor illusions are the * illusory arm extension and the *Pinocchio illusion. Vibration-induced illusory movement experiences were first described in 1972 in two separate and independent publications.
References
Critchley, M. (1965). Disorders of corporeal awareness in parietal disease.In: The body percept. Edited by Wapner, S., Werner, H. New York, NY: Random House.
Eklund, G. (1972). Position sense and state of contraction: The effects of vibration. Journal ofNeurology, Neurosurgery and Psychiatry, 35, 606-611.
Goodwin, G.M., McCloskey, D.I., Matthews, P.B.C. (1972). The contribution of muscle afferents to kinaesthesia shown by vibration induced illusions of movement and by the effects of paralysing joint afferents. Brain, 95, 705-748.
Jones, L.A. (1988). Motor illusions: What do they reveal about proprioception? Psychological Bulletin, 103, 72-86.
Dictionary of Hallucinations. J.D. Blom. 2010.