Acquired prosopagnosia

Although in the second half of the 1800’s Charcot and Wilbrand have already written about a patient who has mistaken his dog for his doctor (Séra, 2008), the term prosopagnosia originates from about hundred years later, when Bodamer (1947) described a face recognition impairment in three II. World War veterans. None of these patients were purely prosopagnosic, but they brought such fame to Bodamer that his studies are still being quoted in every prosopagnosia-related article. One of his patients could not even recognize his closest acquaintances, but he did immediately recognize Hitler because of his unique hairstyle and mustache. Bodamer have noticed that after the injury, his patients identified people through facial details and other compensation mechanisms, such as voices or other characteristic traits (Ellis, 1996).

The acquired form of the disorder can be caused by several factors and it rarely affects face recognition exclusively. One of these rare cases was a patient of Henley and Rains (1999), who – due to a meningitis infection shortly after birth – was unable to recognize himself or his parents, although his object recognition, language and memory skills remained normal, or not impaired to such extent that it would explain the face recognition disorder.

Acquired prosopagnosia can be divided into different subtypes. The most common classification is apperceptive and associative prosopagnosia as subgroups (Damasio, Tranel, & Damasio, 1990). In the first case, lower level(s) of perception are disrupted, and in the second, access to semantic information is impaired. The acquired version of prosopagnosia has long been viewed as a special chance to get an insight into the mechanisms of normal face perception.

The acquired disorder is relatively frequent since better health care options are available for brain injured people (nowadays it is possible to survive a stroke which would have caused death just a few decades ago). However, the congenital type is rare (but not so much as it was formerly thought).