Visual form-processing deficits: a global clinical classification.
BACKGROUND
Patients who have difficulties recognising visual form stimuli are usually labelled as having visual agnosia. However, recent studies let us identify different clinical manifestations corresponding to discrete diagnostic entities which reflect a variety of deficits along the continuum of cortical visual processing.


METHODS
We reviewed different clinical cases published in medical literature as well as proposals for classifying deficits in order to provide a global perspective of the subject. Here, we present the main findings on the neuroanatomical basis of visual form processing and discuss the criteria for evaluating processing which may be abnormal. We also include an inclusive diagram of visual form processing deficits which represents the different clinical cases described in the literature. Lastly, we propose a boosted decision tree to serve as a guide in the process of diagnosing such cases.


CONCLUSIONS
Although the medical community largely agrees on which cortical areas and neuronal circuits are involved in visual processing, future studies making use of new functional neuroimaging techniques will provide more in-depth information. A well-structured and exhaustive assessment of the different stages of visual processing, designed with a global view of the deficit in mind, will give a better idea of the prognosis and serve as a basis for planning personalised psychostimulation and rehabilitation strategies.
Departamento de Psicología Básica, Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Salamanca, Salamanca, España. Electronic address: jaime_ua@usal.es.
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J
Unzueta-Arce
Departamento de Psicología Básica, Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Salamanca, Salamanca, España.
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R
García-García
Departamento de Psicología Básica, Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Salamanca, Salamanca, España.
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Ladera-Fernández
Departamento de Psicología Básica, Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Salamanca, Salamanca, España.
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MV
Perea-Bartolomé
Departamento de Psicología Básica, Psicobiología y Metodología de las Ciencias del Comportamiento, Universidad de Salamanca, Salamanca, España.
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S
Mora-Simón
Servicio de Neurología, Hospital Universitario de Salamanca, Salamanca, España.
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J
Cacho-Gutiérrez
D000377:Agnosia / Q000145:classification*; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D009483:Neuropsychological Tests; D014786:Vision Disorders / Q000145:classification*; D014796:Visual Perception / Q000502:physiology*