Allesthesia

Definition

Misperception of the location of a stimulus. Although it can occur in other modalities, it is most commonly elicited by tactile stimulation and is often seen in the presence of other symptoms of unilateral asomatognosia. If a tactual stimulus is applied to the side of the body contralateral to a hemispheric lesion, the allesthetic patient may perceive the nature of the stimulus correctly but identify it as being applied to the comparable area on the opposite (unaffected) side of the body. In some instances the stimulus may be perceived as being on the same side of the body to which it was applied, but displaced significantly from the point of the actual stimulation (usually toward the midline). When present, this phenomenon likely results from post-rolandic (parietal) lesions of the right rather than the left hemisphere. More rarely it has been associated with brainstem lesions.

Cross-References

• Asomatognosia