Abstract Details

Title Network Localization of Visual Anosognosia from 28 Cases of Anton Syndrome

Topic Aging, Dementia, and Behavioral Neurology

Presentation(s) P3 - Poster Session 3 (5:30 PM-6:30 PM)

Poster/Presentation
Number 7-001

Background Visual anosognosia (also called Anton or Anton-Babinski syndrome) is a condition where patients suffer a brain injury that causes both cortical blindness and unawareness of the visual deficit. Due to the rarity of visual anosognosia, there is limited formal analysis exploring its underlying neuroanatomical localization beyond that described in rare case reports.

Objective To determine the neural correlates of lack of awareness of cortical blindness in Anton syndrome.

Design/Methods We performed a systematic PRISMA literature review and included cases that reported vision loss, described a lack of awareness of deficit, and provided neuroimaging of sufficient quality for mapping. Some patients with visual anosognosia also confabulate about visual information but this was not a required criteria. We traced the two-dimensional published images, guided by anatomical landmarks, into normalized space. For assessment of functional connectivity disrupted in visual anosognosia, we computed single subject functional connectivity maps using a resting-state functional connectome (fMRI, n = 1000) and then assessed for >95% overlap of networks causing visual anosognosia.

Results Our systematic literature review identified 28 unique cases of visual anosognosia that met our inclusion criteria (19 male, M = 54.8, SD = 24.6). Analysis of single-subject functional connectivity maps (thresholded at t>7) revealed peak overlap in the corpus callosum [-18, -52, 10], posterior cingulate [-10, -50, 4] and lingual gyrus which defines a shared network common to visual anosognosia.

Conclusions Our study suggests that visual anosognosia is associated with the disruption of a functional network defined by the posterior cingulate, corpus callosum and parts of the visual associate cortices. Some of these regions have been implicated in other forms of anosognosia and may be elements of a metacognitive awareness network. While this research was limited by the availability of only two-dimensional images the results help identify neuroanatomical regions disrupted in this rare syndrome.

Authors/Disclosures
Kyla A. Gaudet (Wheaton College) PRESENTER	Ms. Gaudet has nothing to disclose.
Michael D. Fox, MD, PhD (Brigham and Women's Hospital / Harvard Medical School)	Dr. Fox has received personal compensation in the range of $500-$4,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Wiley.
Isaiah Kletenik, MD (BRIGHAM AND WOMEN’S HOSPITAL)	The institution of Dr. Kletenik has received research support from NIH.