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S9-2 Factors influencing ERPs
29th International Congress of Clinical Neurophysiology S8-5 Brain computer interfaces for communication and control of robotic devices and domotic applications: possible role for clinical applications F. Babiloni1 , D. Mattia2 , F. Cincotti2 1 Department of Physiology and Pharmacology, University of Rome Sapienza, Rome, Italy, 2 IRCCS Fondazione Santa Lucia, via Ardeatina 306, 00179, Roma, Italy Aim: The aim of this paper is to analyze whether the use of the cortical activity estimated from non invasive EEG recordings could be useful to detect mental states related to the imagination of limb movements and how this technology could be useful in clinical applications. Methods: Estimation of cortical activity was performed on high resolution EEG data related to the imagination of limb movements and detection of P300 gathered in a group of normal healthy subjects by using realistic head models. Cortical activity was estimated in Region of Interest associated with the subjects Brodmann areas by using depth-weighted minimum norm solutions. Comparisons between surface recorded EEG and the estimated cortical activity were performed. Subjects are asked to interact with different electronic devices of common use by using such BCI system. A restricted group of patients suffering by cerebral stroke were also involved in the BCI experiments. Motor imagery for stroke patients is used in the context of rehabilitation tasks. Results: With the proposed methodology healthy users are able to drive several mechanical and electronic devices by modulating their EEG activity related to motor imagery. BCI-based P300 is found a methodology easier to use for the stroke patients than motor imagery for driving devices. Rehabilitation tasks in patients involving motor imagery could be checked by using BCI system. Conclusions: EEG recordings can be used to drive electronic and mechanical devices in healthy and in a group of patients suffering from stroke. An possible role of BCI system in rehabilitation tasks for certain class of stroke patients has been investigated. The presented approach could extend the possibility for a use of BCI system into the rehabilitation path for those patients. S9. Physiological studies of cognitive functions S9-1 Cognitive neuroelectric measures in the clinic J. Polich1 1 Molecular and Integrative Neurosciences Department, The Scripps Research Institute, La Jolla, California, USA Cognitive event-related potentials (ERPs) have been studied for at least 50 years. Despite their responsivity to neurologic and psychiatric disorders, neuroelectric evaluation has not been adopted as a routine clinical assessment tool. Several largely tractable and historical factors contributed to this outcome: (1) inter-subject measurement variability, (2) failure to standardize disease-based ERP methodologies, and (3) the concomitant emergence of other neuroimaging techniques. The present overview will highlight the historical origins of these issues, how the technical challenges can be addressed, with directions suggested by contemporary empirical and theoretical findings. Clinically reliable neuroelectric measures that quantify cognitive dysfunction will be of considerable benefit as present populations age beyond the years of previous generations. S9-2 Factors influencing ERPs C.A. Tomberg1 1 Brain Research Unit, Faculty of Medecine, University of Brussels, Brussels, Belgium Event-related potentials are giving valuable marks of brain information processing. Each stage is influenced by numerous factors modulating cognitive resources involvement. Their management is dependent on intrinsic brain states as well as on external interactions. From molecular contribution to genetic and drugs influences an overview of these factors will be presented in physiological as well as in pathophysiological states.
S19 S9-3 Cognitive VEPs Y. Kuroiwa1 1 Department of Neurology, Graduate School of Medicine, Yokohama City University Introduction: A P300 component is independent of motor processing and is a useful parameter in studying cognitive processing in a variety of normal and clinical populations. P300 testing is a viable approach that may prove helpful for the evaluation of implicit information-processing capabilities The Methods: ERPs, SPECT, motor disability score, and WAIS-R were studied in 22 PD patients and 23 normal controls (NC). Visual ERPs and reaction time were measured at different interstimulus intervals in patients with PD. Results: (1) ERPs and reaction time were correlated with motor disability score. (2) ERPs tended to be more strongly correlated with WAIS-R scores than with MD scores. (3) We found negative correlation of P300 latencies and reaction time to rCBF changes. (4) We found positive correlation of P300 amplitude to rCBF changes. (5) The influence of group was characterized by longer latency for P300, N200, and reaction time and decreased P300 amplitude in PD than in NC. (6) Both P300 latency and reaction time to rare targets in PD showed significantly longer latency in long ISI condition compared to short ISI condition. Discussion: (1) We measured visual event-related potentials and reaction time during oddball and S1-S2 tasks at different interstimulus intervalsin patients with Parkinson disease. (2) The major findings of the present study were the influence of group, and ISI influence on P300 latency to rare targets, occurring only in PD. (3) The influence of group was characterized by longer latency for P300, N200, and reaction time and decreased P300 amplitude in PD than in NC. (4) ERPs and reaction time were correlated with WAIS-R, motor disability, and cerebral blood flow. (5) Both P300 latency and reaction time in PD showed significantly longer latency in long ISI condition compared to short ISI condition. (6) Our results indicate that ISI manipulations significantly influence the time required for cognitive processing in PD. S9-4 Cognitive ERPs in Fragile X-associated Tremor Ataxia Syndrome (FXTAS) and early Alzheimer’s Disease J. Olichney1,6 , M. Kutas2 , V. Iragui3 , F. Tassone4 , R. Hagerman4,5 Department of Neurology, University of California, Davis, CA, USA, 2 Department of Cognitive Science, University of California, San Diego, 3 Department of Neurosciences, University of California, San Diego, 4 MIND Institute, University of California, Davis, 5 Department of Pediatrics, University of California, Davis, 6 Center for Mind and Brain, University of California, Davis 1
Background: FXTAS is a recently described neurodegenerative disorder associated with premutation alleles (55 200 CGG repeats) of the FMR1 gene. Full mutations (>200 repeats) cause gene silencing and fragile X syndrome, the most common cause of inherited cognitive impairment. Patients with FXTAS typically display cerebellar ataxia, peripheral neuropathy, and cognitive impairment in the later stages. At autopsy, FXTAS brains typically have numerous intranuclear inclusions in the hippocampus and neocortex, both in neurons and astrocytes. Objective: While a ‘frontal-subcortical’ predominance of cognitive deficits has been described in FXTAS (Grigsby et al, Neuropsychology 2008), studies of standard clinical neuropsychological tests have not found any robust discrimination between FXTAS and Alzheimer’s Disease (Seritan et al, Neuropsychiatric Genetics 2008). One possible explanation for this is that FXTAS inclusions are particularly numerous in the hippocampus, a predilection site for AD neurofibrillary pathology as well. In this presentation, I will review the findings of prior studies of the auditory P300 and our ERP studies of word repetition in AD and compare these to recent data acquired in >50 patients with FXTAS. Results: One of the major ERP findings in FXTAS was a severe decrement of the N400 word repetition effect. In contrast to AD, the P600 word repetition effect is often of normal amplitude, except in those FXTAS patients who demonstrate the most severe verbal memory deficits. Higher mRNA levels for FMR1 are correlated with reduced N400 amplitudes in FXTAS, which suggests a major modulatory role of the FMR1 gene and FMRP protein upon synaptic excitability. The prognostic significance of abnormal N400 and P600 word repetition effects in very early stage AD (i.e. in the ‘Mild cognitive impairment’ stage) will also be discussed.
S19 S9-3 Cognitive VEPs Y. Kuroiwa1 1 Department of Neurology, Graduate School of Medicine, Yokohama City University Introduction: A P300 component is independent of motor processing and is a useful parameter in studying cognitive processing in a variety of normal and clinical populations. P300 testing is a viable approach that may prove helpful for the evaluation of implicit information-processing capabilities The Methods: ERPs, SPECT, motor disability score, and WAIS-R were studied in 22 PD patients and 23 normal controls (NC). Visual ERPs and reaction time were measured at different interstimulus intervals in patients with PD. Results: (1) ERPs and reaction time were correlated with motor disability score. (2) ERPs tended to be more strongly correlated with WAIS-R scores than with MD scores. (3) We found negative correlation of P300 latencies and reaction time to rCBF changes. (4) We found positive correlation of P300 amplitude to rCBF changes. (5) The influence of group was characterized by longer latency for P300, N200, and reaction time and decreased P300 amplitude in PD than in NC. (6) Both P300 latency and reaction time to rare targets in PD showed significantly longer latency in long ISI condition compared to short ISI condition. Discussion: (1) We measured visual event-related potentials and reaction time during oddball and S1-S2 tasks at different interstimulus intervalsin patients with Parkinson disease. (2) The major findings of the present study were the influence of group, and ISI influence on P300 latency to rare targets, occurring only in PD. (3) The influence of group was characterized by longer latency for P300, N200, and reaction time and decreased P300 amplitude in PD than in NC. (4) ERPs and reaction time were correlated with WAIS-R, motor disability, and cerebral blood flow. (5) Both P300 latency and reaction time in PD showed significantly longer latency in long ISI condition compared to short ISI condition. (6) Our results indicate that ISI manipulations significantly influence the time required for cognitive processing in PD. S9-4 Cognitive ERPs in Fragile X-associated Tremor Ataxia Syndrome (FXTAS) and early Alzheimer’s Disease J. Olichney1,6 , M. Kutas2 , V. Iragui3 , F. Tassone4 , R. Hagerman4,5 Department of Neurology, University of California, Davis, CA, USA, 2 Department of Cognitive Science, University of California, San Diego, 3 Department of Neurosciences, University of California, San Diego, 4 MIND Institute, University of California, Davis, 5 Department of Pediatrics, University of California, Davis, 6 Center for Mind and Brain, University of California, Davis 1
Background: FXTAS is a recently described neurodegenerative disorder associated with premutation alleles (55 200 CGG repeats) of the FMR1 gene. Full mutations (>200 repeats) cause gene silencing and fragile X syndrome, the most common cause of inherited cognitive impairment. Patients with FXTAS typically display cerebellar ataxia, peripheral neuropathy, and cognitive impairment in the later stages. At autopsy, FXTAS brains typically have numerous intranuclear inclusions in the hippocampus and neocortex, both in neurons and astrocytes. Objective: While a ‘frontal-subcortical’ predominance of cognitive deficits has been described in FXTAS (Grigsby et al, Neuropsychology 2008), studies of standard clinical neuropsychological tests have not found any robust discrimination between FXTAS and Alzheimer’s Disease (Seritan et al, Neuropsychiatric Genetics 2008). One possible explanation for this is that FXTAS inclusions are particularly numerous in the hippocampus, a predilection site for AD neurofibrillary pathology as well. In this presentation, I will review the findings of prior studies of the auditory P300 and our ERP studies of word repetition in AD and compare these to recent data acquired in >50 patients with FXTAS. Results: One of the major ERP findings in FXTAS was a severe decrement of the N400 word repetition effect. In contrast to AD, the P600 word repetition effect is often of normal amplitude, except in those FXTAS patients who demonstrate the most severe verbal memory deficits. Higher mRNA levels for FMR1 are correlated with reduced N400 amplitudes in FXTAS, which suggests a major modulatory role of the FMR1 gene and FMRP protein upon synaptic excitability. The prognostic significance of abnormal N400 and P600 word repetition effects in very early stage AD (i.e. in the ‘Mild cognitive impairment’ stage) will also be discussed.