title: Impairments in the Face-Processing Network in Developmental Prosopagnosia and Semantic Dementia.
abstract: BACKGROUND
  Developmental prosopagnosia (DP) and semantic dementia (SD) may be the two most common neurologic disorders of face processing, but their main clinical and pathophysiologic differences have not been established. To identify those features, we compared patients with DP and SD.
  
  
  METHODS
  Five patients with DP, five with right temporal-predominant SD, and ten normal controls underwent cognitive, visual perceptual, and face-processing tasks.
  
  
  RESULTS
  Although the patients with SD were more cognitively impaired than those with DP, the two groups did not differ statistically on the visual perceptual tests. On the face-processing tasks, the DP group had difficulty with configural analysis and they reported relying on serial, feature-by-feature analysis or awareness of salient features to recognize faces. By contrast, the SD group had problems with person knowledge and made semantically related errors. The SD group had better face familiarity scores, suggesting a potentially useful clinical test for distinguishing SD from DP.
  
  
  CONCLUSIONS
  These two disorders of face processing represent clinically distinguishable disturbances along a right hemisphere face-processing network: DP, characterized by early configural agnosia for faces, and SD, characterized primarily by a multimodal person knowledge disorder. We discuss these preliminary findings in the context of the current literature on the face-processing network; recent studies suggest an additional right anterior temporal, unimodal face familiarity-memory deficit consistent with an "associative prosopagnosia."
authors.affiliation: *Departments of Neurology and Psychiatry & Biobehavioral Sciences, David Geffen School of Medicine, The University of California at Los Angeles, Los Angeles, California †Veterans Affairs Greater Los Angeles Healthcare Center, Los Angeles, California.
authors.forename: Mario F
authors.initials: MF
authors.lastname: Mendez
authors.forename: John M
authors.initials: JM
authors.lastname: Ringman
authors.forename: Jill S
authors.initials: JS
authors.lastname: Shapira
mesh_terms: D000328:Adult; D000368:Aged; D000066499:Facial Recognition / Q000502:physiology*; D005260:Female; D057180:Frontotemporal Dementia / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D020238:Prosopagnosia / Q000503:physiopathology*