Occipital lobe dysfunction revealed by functional brain imaging in a patient with traumatic visual field loss

Abstract

We report a patient with visual field loss due to closed head trauma who was imaged with anatomic and functional brain imaging. The findings of ophthalmologic examination were normal except for a complete homonymous hemianopia on the right, an incongruous homonymous hemianopia on the left, and right oculomotor palsy. The results of anatomic brain imaging, computed tomography, and magnetic resonance imaging (MRI) were unremarkable. However, single-photon emission computed tomography (SPECT) scan revealed marked hypoperfusion of the left occipital lobe and functional MRI showed a corresponding strikingly reduced response to visual stimuli in the left occipital lobe. Therefore, this patient is thought to have had dysfunction of the left occipital lobe. Functional brain imaging techniques, such as SPECT and functional MRI, can be helpful in the localization of the responsible lesions even when conventional neuro-imagings are nondiagnostic.