Altered state of corporal consciousness related to alien hand syndrome and schizophrenic motor passivity.

Some patients with schizophrenia present a related phenomenon in which they believe their limbs are under the control of an alien force (motor passivity).5 There are some attempts to elucidate the nature and mechanism of passivity phenomena (experiences that one’s conscious actions or thoughts have not been ‘willed’ by oneself) wich include the dysfunction of an internal self-monitoring system that normally enables the distinction between internally generated actions and external influences on intentional behavior. Motor imagery is the mental simulation of specific motor actions and it is based upon the internal representation of intended but unexecuted motor actions.5 We propose, therefore, that alien limb phenomenon can represent a very bizarre kind of altered state of body consciousness related to a right hemisphere disturbance and that they share symptomatological characteristics and possible pathogenic grounds with the schizophrenic motor passivity.