Also known asand. The term negative autoscopy is used to denote a variant of *autoscopy (i.e. the perception of a hallucinated image of oneself) characterized by the transient failure to perceive one's own mirror image while looking into a reflecting surface such as a mirror. Reports of negative autoscopy are extremely rare. In his classic work on autoscopy, the French physician and psychologist Paul Auguste Sollier (1861-1933) mentions three cases of negative autoscopy. In two of these cases, the affected individual is described as being unable to perceive his own reflection in the mirror.In one of these cases, the reflection reportedly returned after half an hour. In the third case, the inability to perceive a mirror image was attributable to the interference by lively * visual hallucinations depicting various scenes and unknown faces (i.e. * facial hallucinations). Sollier suspected that two of the three cases may have been due to hysteria. He employed the term negative autoscopy in opposition to the term * positive autoscopy, or what is today known simply as autoscopy. Conceptually, negative autoscopy is related to * mirrored self-misidentification. In a conceptual and phenomenological sense, it has also been linked to prosopagnosia (i.e. 'face blindness'), especially in those cases where a reflection in the mirror is misidentified as someone else's. This 'incomplete' type of negative autoscopy has been designated bytheFrenchpsy-chiatrists Henri Hécaen (1912-1983) and Julian de Ajuriaguerra (1911-1993) as a variant of * autotopagnosia. Negative autoscopy may be classified as a *cognitive illusion. It has also been classified as a *negative hallucination which is restricted to one's own body. In the latter reading, the notion ofnegative autoscopy includes the inability to perceive one's body directly, either in part (i.e. seeing only one side of the body) or in whole. Negative autoscopy may be accompanied by *aschematia or *acenesthesia.