Event Abstract Back to Event Suppressed SSVEP strength in stroke patients with unilateral spatial neglect Masato Shimura1, Yumie Ono1*, Satoko Omatsu2 and Takanori Tominaga2 1 Meiji University, Department of Electronics and Bioinformatics, Japan 2 Murata Hospital, Department of Rehabilitation, Japan Introduction: Previous studies demonstrated that attention to the visual stimulus enhances the strength of the SSVEP signals in healthy adults, suggesting that the attention-related increase in the SSVEP response may represent the strength of attention oriented to the visual stimulus. We therefore compared the attention-related increase in the SSVEP response among healthy controls, stroke patients with unilateral spatial neglect (USN), and those without USN to better understand the mechanism between attention and primary visual processing in patients with USN. Methods:Ten healthy young adults and 14 stroke patients participated in the experiment. Four out of 14 stroke patients were with USN. EEG was measured from PO7, O1, O2, and PO8 based on the international 10% system. A fixation point was placed at the center position in front of the participants and a flicker stimulus (white LED, 6Hz) was placed on their right or left visual field (45 and 15 degrees in healthy controls and patients, respectively). First, participants watched the fixation point without paying attention to the flicker stimulus. EEG was measured for 30 s for 3 times with each visual field. Second, we conducted the same experiment again except we placed a red LED in the vicinity of the white LED, which blinked randomly 5 or 6 times during the measurement. They were instructed to report the number of the blink of the red LED at the end of the measurement, yielding spontaneous attention of participants to the specific visual field. Results and Discussion: Healthy controls and patients without USN reported correct number (accuracy: 96-100%) of the red LED blinking located at either visual hemifield. Patients with USN reported the number of blinking as correct as other participants (98%) when the red LED was presented to the right visual hemifield but they failed to count more than half number of blinking when it was presented to the left visual hemifield (46%). Wavelet-based time-frequency analysis showed that attention to the visual hemifield robustly enhanced SSVEP strength in the healthy controls. Although patients without USN showed enhanced SSVEP strength by paying attention, the increase in SSVEP response was is smaller than that of healthy controls. The increase of patients with USN in SSVEP response was further smaller than those in patients without USN. Patients with USN showed decreased SSVEP response in case of paying attention to their right side. These results suggest that patients were not able to pay attention than healthy controls. Also, patients with USN could not pay attention to both visual hemifields than those without USN. The pathology of USN even affects the primary visual response of attention-oriented change in SSVEP. Further research would be conducted to study whether the recovery of USN is associated with the recovered strength of SSVEP response in stroke patients. Keywords: SSVEP, Stroke, Unilateral spatial neglect, Visual stimulus, attention-related increase Conference: 2015 International Workshop on Clinical Brain-Machine Interfaces (CBMI2015), Tokyo, Japan, 13 Mar - 15 Mar, 2015. Presentation Type: Poster 1-5 Topic: Clinical Brain-Machine Interfaces Citation: Shimura M, Ono Y, Omatsu S and Tominaga T (2015). Suppressed SSVEP strength in stroke patients with unilateral spatial neglect. Conference Abstract: 2015 International Workshop on Clinical Brain-Machine Interfaces (CBMI2015). doi: 10.3389/conf.fnhum.2015.218.00027 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 23 Apr 2015; Published Online: 29 Apr 2015. * Correspondence: Dr. Yumie Ono, Meiji University, Department of Electronics and Bioinformatics, Tama-ku, Kawasaki, Japan, yumie@meiji.ac.jp Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Masato Shimura Yumie Ono Satoko Omatsu Takanori Tominaga Google Masato Shimura Yumie Ono Satoko Omatsu Takanori Tominaga Google Scholar Masato Shimura Yumie Ono Satoko Omatsu Takanori Tominaga PubMed Masato Shimura Yumie Ono Satoko Omatsu Takanori Tominaga Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.