The P300 is a positive peak in EEG occurring after presentation of a target stimulus. For brain-computer interfaces (BCIs), eliciting P300s by tactile stimuli would have specific advantages; the display can be hidden under clothes and keeps the user’s gaze free. In addition, robust classification is especially important for BCIs. This motivated us to investigate P300s in response to tactile and visual stimuli unimodally and bimodally. Tactile stimuli were delivered by tactors around the participant’s waist. Visual stimuli were flashed circles on a monitor, schematically representing the tactors. Participants attended to the vibrations and/or flashes of a “target” presented in a stream of standards. The P300 amplitude for the different modalities was comparable in size and depended on electrode location. Classification accuracy was highest in the bimodal condition. We conclude that bimodal stimuli could enhance classification results within a BCI context compared to unimodal presentations.
{"title":"Tactile, Visual, and Bimodal P300s: Could Bimodal P300s Boost BCI Performance?","authors":"A. Brouwer, J. V. Erp, F. Aloise, F. Cincotti","doi":"10.3814/2010/967027","DOIUrl":"https://doi.org/10.3814/2010/967027","url":null,"abstract":"The P300 is a positive peak in EEG occurring after presentation of a target stimulus. For brain-computer interfaces (BCIs), eliciting P300s by tactile stimuli would have specific advantages; the display can be hidden under clothes and keeps the user’s gaze free. In addition, robust classification is especially important for BCIs. This motivated us to investigate P300s in response to tactile and visual stimuli unimodally and bimodally. Tactile stimuli were delivered by tactors around the participant’s waist. Visual stimuli were flashed circles on a monitor, schematically representing the tactors. Participants attended to the vibrations and/or flashes of a “target” presented in a stream of standards. The P300 amplitude for the different modalities was comparable in size and depended on electrode location. Classification accuracy was highest in the bimodal condition. We conclude that bimodal stimuli could enhance classification results within a BCI context compared to unimodal presentations.","PeriodicalId":159265,"journal":{"name":"Srx Neuroscience","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131723149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We present a case of a demented patient who experienced a reversible period of superimposed symptoms typical of Ganser syndrome. This is a poorly understood condition characterized by paralogia, clouding of consciousness and dissociative/conversion symptoms. Etiological factors include personal conflicts, organic brain syndromes, and child abuse. Even though more common in young adults, cases of conversion disorder in the elderly have been described as a form of pseudodementia, with functional impairment yet no evidence of organic deterioration. This was a 78 year old married male who came to our geriatric center after a hospitalization for a urinary tract infection, bronchitis and dehydration. The initial psychiatric evaluation offered evidence to rule out delirium, and errors in calculation compatible with paralogia (near right answers), disorientation, and errors in reality testing. Family also gave a history of an insidious and progressive deterioration of his cognition prior to his hospitalization that was not compatible with our initial findings. As well as a conflicting relationship with his ill and dependent wife. The treatment course during the following 12 months showed improvement in his mental status, compatible with the resolution of a superimposed and transient state compatible with Ganser syndrome, in a patient with underlying dementia of the Alzheimer type.
{"title":"Ganser Syndrome in a Patient with Dementia: A Case Report","authors":"B. Ng, E. D. García","doi":"10.3814/2010/219261","DOIUrl":"https://doi.org/10.3814/2010/219261","url":null,"abstract":"We present a case of a demented patient who experienced a reversible period of superimposed symptoms typical of Ganser syndrome. This is a poorly understood condition characterized by paralogia, clouding of consciousness and dissociative/conversion symptoms. Etiological factors include personal conflicts, organic brain syndromes, and child abuse. Even though more common in young adults, cases of conversion disorder in the elderly have been described as a form of pseudodementia, with functional impairment yet no evidence of organic deterioration. This was a 78 year old married male who came to our geriatric center after a hospitalization for a urinary tract infection, bronchitis and dehydration. The initial psychiatric evaluation offered evidence to rule out delirium, and errors in calculation compatible with paralogia (near right answers), disorientation, and errors in reality testing. Family also gave a history of an insidious and progressive deterioration of his cognition prior to his hospitalization that was not compatible with our initial findings. As well as a conflicting relationship with his ill and dependent wife. The treatment course during the following 12 months showed improvement in his mental status, compatible with the resolution of a superimposed and transient state compatible with Ganser syndrome, in a patient with underlying dementia of the Alzheimer type.","PeriodicalId":159265,"journal":{"name":"Srx Neuroscience","volume":"58 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126209423","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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