Delayed diagnosis of prosopagnosia following a hemorrhagic stroke in an elderly man: A case report

Abstract

Background: Acquired prosopagnosia is a rare condition characterized by the loss of familiarity with previously known faces and the inability to recognize new ones. It usually occurs after the onset of brain lesions such as in a stroke. The initial identification of prosopagnosia generally relies on a patient's self-report, which can be challenging if it lacks an associated chief complaint. There were few cases of prosopagnosia presenting purely as eye symptoms in the previous literature confirmed by functional magnetic resonance imaging (MRI).

Case summary: We present a case of delayed diagnosis of prosopagnosia after a right hemisphere stroke in an elderly man whose chief complaint was persistent and progressive "blurred vision" without facial recognition impairment. Ophthalmic tests revealed a homonymous left upper quadrantanopia, with normal visual acuity. He was found by accident to barely recognize familiar faces. The patient showed severe deficit in face recognition and perception tests, and mild memory loss in neuropsychological assessments. Further functional MRI revealed the visual recognition deficits were face-specific. After behavioral intervention, the patient started to rely on other cues to compensate for poor facial recognition. His prosopagnosia showed no obvious improvement eight months after the stroke, which had negative impact on his social network.

Conclusion: Our case demonstrates that the presentation of prosopagnosia can be atypical, and visual difficulties might be a clinical manifestation solely of prosopagnosia, which emphasizes the importance of routinely considering face recognition impairment among elderly patients with brain lesions.

Keywords: Blurred vision; Case report; Diagnosis; Elderly; Functional magnetic resonance imaging; Prosopagnosia; Stroke.

Figure 1

rain magnetic resonance imaging at admission. A-C: Demonstrating a right occipital-temporal lobe hemorrhagic stroke. T1-weighted (A), T2-weighted (B), diffusion-weighted imaging (DWI) (C); D: T1-weighted presenting an occipital-parietal lobe ischemic stroke; E: T2-weighted presenting an occipital-parietal lobe ischemic stroke; F: DWI presenting an occipital-parietal lobe ischemic stroke. Orange arrowheads indicate the lesions.

Figure 2

Visual field defect test showing homonymous left upper quadrantanopia. A: Results of greyscale and pattern deviation at the onset of the stroke. Visual field index (VFI) was 56% in the right eye, and 61% in the left; B: Results of greyscale and pattern deviation after one month. VFI was 74% in both eyes.

Figure 3

Functional magnetic resonance imaging. A: The famous faces task performed two months after the onset of stroke showed activation in the anterior of the bilateral fusiform gyrus that was more significant on the left (red and yellow). The areas of activation are correlated with the fusiform gyrus (blue), which most likely corresponds to the “fusiform face area”; B: The object/landscape task demonstrated activation in the area of the right occipital lobe, which is distinct from the face recognition area.

Figure 4

Case timeline. MRI: Magnetic resonance imaging; OCT: Optical coherence tomography; VEP: Visual Evoked Potential; DTI: Magnetic resonance diffusion tensor imaging.