Visual agnosia and focal brain injury

Rev Neurol (Paris). Jul-Aug 2017;173(7-8):451-460. doi: 10.1016/j.neurol.2017.07.009. Epub 2017 Aug 24.

Abstract

Visual agnosia encompasses all disorders of visual recognition within a selective visual modality not due to an impairment of elementary visual processing or other cognitive deficit. Based on a sequential dichotomy between the perceptual and memory systems, two different categories of visual object agnosia are usually considered: 'apperceptive agnosia' and 'associative agnosia'. Impaired visual recognition within a single category of stimuli is also reported in: (i) visual object agnosia of the ventral pathway, such as prosopagnosia (for faces), pure alexia (for words), or topographagnosia (for landmarks); (ii) visual spatial agnosia of the dorsal pathway, such as cerebral akinetopsia (for movement), or orientation agnosia (for the placement of objects in space). Focal brain injuries provide a unique opportunity to better understand regional brain function, particularly with the use of effective statistical approaches such as voxel-based lesion-symptom mapping (VLSM). The aim of the present work was twofold: (i) to review the various agnosia categories according to the traditional visual dual-pathway model; and (ii) to better assess the anatomical network underlying visual recognition through lesion-mapping studies correlating neuroanatomical and clinical outcomes.

Keywords: Alexia; Orientation agnosia; Prosopagnosia; Topographagnosia; Visual agnosia.

Publication types

  • Review

MeSH terms

  • Agnosia* / classification
  • Agnosia* / diagnosis
  • Agnosia* / etiology
  • Agnosia* / therapy
  • Brain Injuries* / diagnosis
  • Brain Injuries* / etiology
  • Brain Injuries* / physiopathology
  • Brain Injuries* / therapy
  • Brain Mapping
  • Cognition Disorders / physiopathology
  • Humans
  • Nerve Net / physiopathology
  • Neuroimaging
  • Neuropsychological Tests
  • Visual Pathways / physiology
  • Visual Perception / physiology