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Open AccessArticle

Differentiation of Types of Visual Agnosia Using EEG

1
Department of Psychology, Carnegie Mellon University, Pittsburgh, PA 15213, USA
2
Center for the Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, PA 15213, USA
3
Department of Psychology and Center for Integrative Neuroscience, University of Nevada, Reno, NV 89557, USA
4
ARC Centre of Excellence in Cognition and its Disorders, Department of Cognitive Science, Macquarie University, Sydney 2109, Australia
5
School of Psychology, The University of Sydney, Sydney 2006, Australia
6
Department of Electrical and Computer Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
*
Authors to whom correspondence should be addressed.
Shared contribution, alphabetical order.
Vision 2018, 2(4), 44; https://doi.org/10.3390/vision2040044
Received: 5 December 2018 / Revised: 5 December 2018 / Accepted: 13 December 2018 / Published: 18 December 2018
(This article belongs to the Special Issue Visual Perception and Its Neural Mechanisms)
Visual recognition deficits are the hallmark symptom of visual agnosia, a neuropsychological disorder typically associated with damage to the visual system. Most research into visual agnosia focuses on characterizing the deficits through detailed behavioral testing, and structural and functional brain scans are used to determine the spatial extent of any cortical damage. Although the hierarchical nature of the visual system leads to clear predictions about the temporal dynamics of cortical deficits, there has been little research on the use of neuroimaging methods with high temporal resolution to characterize the temporal profile of agnosia deficits. Here, we employed high-density electroencephalography (EEG) to investigate alterations in the temporal dynamics of the visual system in two individuals with visual agnosia. In the context of a steady state visual evoked potential paradigm (SSVEP), individuals viewed pattern-reversing checkerboards of differing spatial frequency, and we assessed the responses of the visual system in the frequency and temporal domain. JW, a patient with early visual cortex damage, showed impaired SSVEP response relative to a control group and to the second patient (SM) who had right temporal lobe damage. JW also showed lower decoding accuracy for early visual responses (around 100 ms). SM, whose lesion is more anterior in the visual system, showed good decoding accuracy initially but low decoding after 500 ms. Overall, EEG and multivariate decoding methods can yield important insights into the temporal dynamics of visual responses in individuals with visual agnosia. View Full-Text
Keywords: visual agnosia; EEG; decoding; SSVEP; neuropsychology visual agnosia; EEG; decoding; SSVEP; neuropsychology
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Haigh, S.M.; Robinson, A.K.; Grover, P.; Behrmann, M. Differentiation of Types of Visual Agnosia Using EEG. Vision 2018, 2, 44.

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