Exosomesthesia or Displacement of Cutaneous Sensation Into Extrapersonal Space

AMONG phenomena that may be apparent during examination of patients with disease of the sensory pathways is mislocalization of a sensory stimulus. It has long been known that a person with a sensory defect, as seen in the common varieties of cerebral hemiplegia, may inaccurately localize stimuli applied on the paretic side. Such point mislocalizations are apparent in examinations using a single stimulus and have been described in detail by Head.1These mislocalizations can be accentuated by the use of double simultaneous stimulation techniques.2In addition, when these techniques of examination are employed, other varieties of mislocalization, such as displacement,3become apparent. Displacement is the patterned mislocalization of one of two stimuli simultaneously applied to different body areas. The direction of displacement is in a definite pattern, which is dependent upon the parts of the body stimulated. Characteristic of mislocalization so far reported has been the fact