Perceptual Visual Inversion Secondary to Inhalation of Fumes of Sulfuryl Chloride (P4-12.003)

Abstract

<h3>Objective:</h3> To describe a case of alteration of visual perception of objects and faces following Inhalation of Sulfuryl Chloride. <h3>Background:</h3> The neural pathways for object perception and recognition include two information-processing streams originating in occipital cortex. Dorsal stream extends to parietal lobe, and Ventral stream extends to inferior temporal lobe. Damage to each pathway can affect elements of visual perception affecting object recognition (what) and spatial perception (where and how). <h3>Design/Methods:</h3> Case report/literature review. <h3>Results:</h3> Fifty-three-year-old woman presented following inhalation of toxic fumes. Over the following hours and days, she lost the ability to speak her native tongue and could only communicate in her second language. She complained that most objects in her visual field were inverted, but not the whole scene. There are few reports of subjective visual field inversion without robust testing. We formulated novel experiments to probe deficits unique to her. On shape from shading (eggs vs. cavities) test, the light on top looked like cavities, unlike neurotypicals - implying that for her, the sun shines from below. She recognized upside-down faces faster than the correct way up and could easily read upside down. Prosopagnosics identify inverted faces more accurately than neurotypicals. We suggest there is a selective injury to the ventral stream,” What Pathway,” in the inferior temporal lobe (associated with object recognition). The insult relatively spared the dorsal stream “How and Where” in the posterior parietal cortex. This may explain why she exhibited mild Balint syndrome (optic ataxia, simultagnosia, oculomotor apraxia). Alternatively, the initial Balint may have been progressively corrected via visual feedback during reaching. Such correction does not occur for the ventral stream because we do not usually palpate people’s faces. <h3>Conclusions:</h3> Inversion of vision is rare but using stimuli designed to probe specific symptoms, we gain insight into cascade of neural signals that culminate in perception. <b>Disclosure:</b> Dr. Ramachandran has nothing to disclose. Dr. Kakawand has nothing to disclose. Dr. McGeoch has nothing to disclose. Mr. Ahern has nothing to disclose. Dr. Tobias has nothing to disclose.