Spatial processing in Bálint syndrome and prosopagnosia: a study of three patients.

Background: Spatial analysis may be subdivided into between-object and within-object spatial coding. We investigated the contribution of various visual cues to grouping processes that might determine whether single or multiple objects were perceived and therefore which type of spatial coding would be used for a stimulus.

Methods: We asked three patients to make shape judgments with a series of displays showing triangular arrangements, moving from more implicit triangles defined by separate objects at the apices (between-object spatial coding) to more explicit triangles with line edges or surface texture (within-object spatial coding).

Investigations of face expertise in the social developmental disorders.

Background: Patients with social developmental disorders (SDD), also known as autism spectrum disorders, may have impaired recognition of facial identity or facial expressions.

Objective: Our goal was to determine whether SDDs were characterized by loss of a perceptual mechanism responsible for face expertise, as current theories suggest that such a loss should be selective for upright faces, disproportionately affect the perception of facial configuration, and possibly be more severe in the eye region.

Method: We tested a group of 24 adult patients with SDD with an oddity paradigm that required them to detect changes in facial configuration or feature color, in either the eyes or the mouth, in both upright and inverted faces.

Perception of facial expression and facial identity in subjects with social developmental disorders.

Background: It has been hypothesized that the social dysfunction in social developmental disorders (SDDs), such as autism, Asperger disorder, and the socioemotional processing disorder, impairs the acquisition of normal face-processing skills. The authors investigated whether this purported perceptual deficit was generalized to both facial expression and facial identity or whether these different types of facial perception were dissociated in SDDs.

Methods: They studied 26 adults with a variety of SDD diagnoses, assessing their ability to discriminate famous from anonymous faces, their perception of emotional expression from facial and nonfacial cues, and the relationship between these abilities.