Prosopagnosia

April 17, 2018 Psychology

PROSOPAGNOSIA Every day a married man wakes up next to a woman he doesn’t recognize. No, he hasn’t been unfaithful; he has prosopagnosia, the inability to recognize or distinguish faces. The woman is his wife, but when he looks at her, he can’t tell who she is. It’s not a memory problem; if you tell the man his wife’s name or if he hears her voice he knows her very well. Prosopagnosia is a type of agnosia. Agnosia is the inability to recognize the import of sensory impressions, according to Dorland’s Medical Dictionary for Health Consumers.

However, prosopagnosia is an inability or difficulty in recognizing familiar faces; it may be congenital or result from injury or disease of the brain, according to the American Heritage® Medical Dictionary. Statistics suggest that 2% of the population may suffer from prosopagnosia or ‘face-blindness’. Prosopagnosia was initially described and studied in detail in the 1947 by Joachim Bodamer, a German neurologist. The aim of this paper is to examine how the cognitive functions and physiological functions combined bring about a specific behaviour in people.

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Prosopagnosia is a neuropsychological condition involving the inability to recognize faces of people they know. It is said to be a neurological, because it involves the brain, any damage done to a specific area of the brain impairs the patient from recognizing faces. The specific area of the brain responsible for this disorder is the fusiform gyrus which is part of the temporal lobe. It is also called the occipitotemporal gyrus.

Researchers infer then that the problem has something to do with the fusiform gyrus itself or in the neural pathways that convey information from that area to other parts of the brain, like the occipital lobe, which processes visual information. so, prosopagnosics usually rely on voice, style of walking, hairstyle, clothing etc. to attain recognition of the person they regularly meet or are in contact with; it could be people as close as their own family members. Types of Prosopagnosia Acquired Prosopagnosia: It occurs after brain damage from stroke, neurodegenerative diseases or head injuries. Individuals with this type of prosopagnosia had normal face recognition abilities in the past which has been impaired or lost due to the brain injury. Imagery is eliminated due to lesions in the anterior temporal lobe. Imagery for facial shape but not features is degraded by lesions of the right hemisphere’s fusiform gyrus, which severely damages perception of facial configuration. Feature imagery was degraded only when there was associated left occipito-temporal damage. Associative Prosopagnosia is thought to be an impairment to the neural pathways between early face perception processes and the related information we hold about people in our memories, which are stored in the hippocampus. Prosopagnics with this type of prosopagnosia can recognize faces and distinguishing them apart by looking at pictures. They can also determine the age and gender of the person. However, they cannot remember any information about the person such as their name, profession or what they did the last time they met that person. ) Apperceptive prosopagnosia’s is said to be a disorder of some of the earliest processes in the face perception system. People with this disorder can’t make any sense of faces and are unable to distinguish between different faces when they are presented with pictures. They may also be unable to work out attributes such as age or gender from a face. However, they may be able to recognise people based on non-face clues such as their clothing, hairstyle or voice. 3) Developmental prosopagnosia is thought to be a form of ‘congenital prosopagnosia’, and that some people are born with a selective impairment in recognizing and perceiving faces.

Individuals with this type often do not realize until they are older that they are unable to recognize faces as well as other people do. Some researchers believe that developmental prosopagnosia may be inherited, since it appears to be present in more than one individual in some families. In 2005, German researchers found evidence of a genetic foundation for the disorder by studying individuals with prosopagnosia in seven families. It is also thought that developmental prosopagnosia is present in children with autism and Asperger syndrome.

Children with these disorders have impaired social development, and prosopagnosia might cause or contribute to their difficulty in relating to other people. A case of developmental prosopagnosia was observed in KD, a fourteen month old girl. At this age, KD was found to be unable to discriminate her own face, as well as her parents, from other strangers. After conducting tests, it was found that KD could match faces by looking at each feature individually. This was a way for KD to cope with her problem. KD’s specific prosopagnosia allowed her to understand expression, a trait commonly lost with those suffering from it.

Besides that, she faced problems with the detection of familiar faces as well as the ability to determine someone’s age and gender by visual clues alone. She compensated by using external stimuli. After formal tests it was concluded that KD had ‘co-morbid visual impairments’, she also had problems with color vision and the discrimination of objects. However, KD did learn how to read despite her problems. It was determined that there were problems occurring at the level of most basic encoding processes in her brain for face recognition.

This case study showed just how early face recognition develops and how soon prosopagnosia can become a problem. Another case study of prosopagnosia McNeil and Warrington (1993) described the case of WJ, 51-year-old man, who suffered a series of strokes which resulted in lesions to the left occipital, left frontal and left temporal lobes causing profound prosopagnosia. When shown a set of three photographs of one famous and two familiar faces, WJ was no able to distinguish the famous face. However, when this task was modified by giving WJ the name of the famous person in the trial (asking “which one is …….? ) performance improved considerably, indicating some covert recognition of these famous faces. Following the onset of his prosopagnosia, WJ acquired a flock of sheep which he photographed for McNeil and Warrington. WJ knew his sheep by number, and McNeil and Warrington were able to determine that he could recognize at least eight out of sixteen pictures of these ‘known sheep’ (this is probably an underestimate- McNeil and Warrington report that on several trials WJ could recognize the sheep but not remember its number, making comments such as “this sheep had three lambs this year. ). This is a notable evidence of an ability to learn to recognize individual sheep while still being profoundly prosopagnosic for human faces. In order to ensure that this ability was not attributable to some characteristic specific to WJ’s own sheep, McNeil and Warrington obtained photographs of ‘unknown sheep’ and managed to recruit two control subjects who had also acquired flocks of sheep after retiring, together with a number of age and profession matched non-sheep and then shown these eight randomly mixed with eight ‘distracter’ sheep.

The subjects were required to say where each picture was one of the original eight or was a distracter sheep. Understandably, the control subjects, both sheep-owning and ‘normal’, found this difficult task and their performance was poor compared to that with human faces. WJ showed the opposite pattern of results, performing rather well on the sheep task (correctly recognizing 81 % of unknown and 87% of the known sheep-better than any other subject), and performed very badly with human faces.

This remarkable case, and McNeil and Warrington’s ingenious investigation of it, thus provide clear evidence that WJ was able to recognize individual sheep on the basis of their photographs, despite being profoundly prosopagnosic for human faces. Individuals with prosopagnosia must learn other ways of remembering faces. Clues such as hair, voice, and clothes may help identify people. Discomfort in social situations due to prosopagnosia may cause a person to become shy and withdrawn.

Many individuals with the disorder report difficulty watching movies and television shows since they cannot identify the characters from one scene in the next. Researchers are working on ways to help individuals with prosopagnosia improve their face recognition. Bibliography: http://rarediseases. about. com/od/rarediseasesp/a/prosopagnosia. htm http://www. faceblind. org/research/ http://www-psychology. concordia. ca/fac/deAlmeida/PSYC352/Pages/Young-2001-prosopagnosia. pdf http://prosopagnosia. totallyexplained. com/ http://books. oogle. co. in/books? id=3GkVAAAAIAAJ=PA87=PA87=famous+case+study+for+prosopagnosia=bl=3ob0NYkqe7=o6DnDaKuZGNYWmdRojxXHfIIYrc=en=eVabSphLybC2B8TY8MgE=X=book_result=result=1#v=onepage=famous%20case%20study%20for%20prosopagnosia=false http://electronics. howstuffworks. com/gadgets/high-tech-gadgets/facial-recognition. htm http://en. wikipedia. org/wiki/Prosopagnosia#Subtypes http://www. macalester. edu/psychology/whathap/UBNRP/visionwebsite04/prosopagnosia%20types. html

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