Disorders of Higher-order Visual Function.

OBJECTIVE

This article provides an overview of disorders of higher-order visual function, encompassing key clinical features, methods for clinical assessment, anatomic localization, and etiologies associated with these disorders. A review of the organization and properties of the brain's visual system is introduced to enhance understanding and facilitate clinical recognition of higher-order visual dysfunction.

LATEST DEVELOPMENTS: Advances in the visual neurosciences have increased our understanding of the underlying properties of visual neurons. New therapies are available to treat diseases that impact cortical neurons and their white matter connections. Thus, recognizing the signs and symptoms of these disorders and using the proper assessment tools to measure dysfunction are essential for preventing disability.

ESSENTIAL POINTS: Functional specialization for distinct visual features defines higher-order visual regions and their corresponding networks. Damage to specialized regions along the occipitoparietal pathway leads to impaired motion processing and visuospatial perception, whereas damage to the occipitotemporal regions results in visual agnosia, including impaired color, object, and facial recognition. Patients experiencing higher-order visual dysfunction do not express symptoms significantly different from those with ocular disorders. Identifying higher-order visual dysfunction requires knowledge of the anatomy and visual properties of neurons in these regions. Assessment of higher-order visual functions can be incorporated into the neurologic mental status examination and prevent delays in diagnosis.