RESUMO
OBJECTIVES: To investigate the characteristics and objective assessment method of visual field defects caused by optic chiasm and its posterior visual pathway injury. METHODS: Typical cases of visual field defects caused by injuries to the optic chiasm, optic tracts, optic radiations, and visual cortex were selected. Visual field examinations, visual evoked potential (VEP) and multifocal visual evolved potential (mfVEP) measurements, craniocerebral CT/MRI, and retinal optical coherence tomography (OCT) were performed, respectively, and the aforementioned visual electrophysiological and neuroimaging indicators were analyzed comprehensively. RESULTS: The electrophysiological manifestations of visual field defects caused by optic chiasm injuries were bitemporal hemianopsia mfVEP abnormalities. The visual field defects caused by optic tract, optic radiation, and visual cortex injuries were all manifested homonymous hemianopsia mfVEP abnormalities contralateral to the lesion. Mild relative afferent pupil disorder (RAPD) and characteristic optic nerve atrophy were observed in hemianopsia patients with optic tract injuries, but not in patients with optic radiation or visual cortex injuries. Neuroimaging could provide morphological evidence of damages to the optic chiasm and its posterior visual pathway. CONCLUSIONS: Visual field defects caused by optic chiasm, optic tract, optic radiation, and visual cortex injuries have their respective characteristics. The combined application of mfVEP and static visual field measurements, in combination with neuroimaging, can maximize the assessment of the location and degree of visual pathway damage, providing an effective scheme for the identification of such injuries.
Assuntos
Lesões Encefálicas Traumáticas , Traumatismos do Nervo Óptico , Humanos , Quiasma Óptico/diagnóstico por imagem , Quiasma Óptico/patologia , Vias Visuais/diagnóstico por imagem , Vias Visuais/patologia , Campos Visuais , Potenciais Evocados Visuais , Técnica de Amplificação ao Acaso de DNA Polimórfico , Hemianopsia/etiologia , Hemianopsia/complicações , Transtornos da Visão/diagnóstico , Transtornos da Visão/etiologia , Transtornos da Visão/patologia , Traumatismos do Nervo Óptico/diagnóstico por imagem , Lesões Encefálicas Traumáticas/diagnóstico , Lesões Encefálicas Traumáticas/diagnóstico por imagemRESUMO
Visual event-related potential (ERP) is an electrophysiological technique that objectively reflects the cognitive processing of stimulus from the perspective of detecting and recording neural electrophysiology responses using different paradigms of visual stimuli. Its endogenous components are closely related to advanced psychological activities. This article introduces the characteristics of main endogenous components including visual mismatch negativity (vMMN), N200 and P300, reviews the research progress of visual ERP in the sequelae of brain injury and objective evaluation of visual function, and prospects the application prospect of visual ERP in the field of forensic medicine.