Decrease of evoked delta, theta and alpha coherences in Alzheimer patients during a visual oddball paradigm

In this study event related coherence of patients with Alzheimer type of dementia (AD) was analyzed by using a visual oddball paradigm as stimuli. A total of 21 mild probable AD subjects (10 untreated, 11 treated) were compared with a group of 19 healthy controls. The members of the groups had their EEG recorded from 12 electrodes by means of a visual oddball paradigm. The evoked coherence was analyzed for delta (1-3.5 Hz), theta (4-7 Hz) and alpha (8-13 Hz) frequency ranges for inter-hemispheric (F3-F4, C3-C4, T3-T4, T5-T6, P3-P4, O1-O2) and long range intra-hemispheric (F3-P3, F4-P4, F3-T5, F4-T6, F3-O1, F4-O2) electrode pairs. The control group showed higher values of evoked coherence in "delta", "theta" and "alpha" bands in the left fronto-parietal electrode pairs in comparison with the untreated AD group (p<0.01 for all frequency bands). Furthermore, the control group showed higher values of evoked coherence in the left fronto-parietal electrode pair in theta frequency band (p<0.01) and higher values of evoked coherence in the right fronto-parietal electrode pair in delta band (p<0.01) when compared to treated AD group. The only significant difference between the treated and untreated AD groups was in the alpha band. The treated AD group showed higher values of evoked coherence at the left fronto-parietal pair in alpha band in comparison to the untreated AD group (p<0.01). During a working memory process the coherence in the left fronto-parietal electrode pair (F3-P3) of AD patients is significantly decreased, thus indicating reduced connectivity between frontal and parietal sites.

[1]  Manuel Schabus,et al.  Fronto-parietal EEG coherence in theta and upper alpha reflect central executive functions of working memory. , 2005, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[2]  Österreichische Akademie der Wissenschaften,et al.  Eeg and Thinking: Power and Coherence Analysis of Cognitive Processes , 1998 .

[3]  E. Basar,et al.  Increased frontal phase-locking of event-related theta oscillations in Alzheimer patients treated with cholinesterase inhibitors. , 2007, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[4]  Bradley T. Hyman,et al.  Neurofibrillary tangles but not senile plaques parallel duration and severity of Alzheimer's disease , 1992, Neurology.

[5]  W. R. Adey,et al.  Hippocampal slow waves. Distribution and phase relationships in the course of approach learning. , 1960, Archives of neurology.

[6]  G. Adler,et al.  EEG coherence in Alzheimer’s dementia , 2003, Journal of Neural Transmission.

[7]  W. R. Adey.  Cell Membranes, Electromagnetic Fields, and Intercellular Communication , 1989 .

[8]  J. Polich,et al.  Cognitive and biological determinants of P300: an integrative review , 1995, Biological Psychology.

[9]  T. Bullock,et al.  EEG coherence has structure in the millimeter domain: subdural and hippocampal recordings from epileptic patients. , 1995, Electroencephalography and clinical neurophysiology.

[10]  E. Basar,et al.  Event-related theta rhythms in cat hippocampus and prefrontal cortex during an omitted stimulus paradigm. , 1994, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[11]  D Liberati,et al.  EEG coherence in Alzheimer's disease. , 1998, Electroencephalography and clinical neurophysiology.

[12]  M. Tanaka,et al.  Periodic appearance of theta rhythm in the frontal midline area during performance of a mental task. , 1980, Electroencephalography and clinical neurophysiology.

[13]  Jean-François Dartigues,et al.  The 9 year cognitive decline before dementia of the Alzheimer type: a prospective population-based study. , 2005, Brain : a journal of neurology.

[14]  E Halgren,et al.  Cognitive evoked potentials as modulatory processes in human memory formation and retrieval. , 1987, Human neurobiology.

[15]  Erol Başar,et al.  Integrative brain function. Neurophysiology and cognitive processes , 1999 .

[16]  T. Bullock,et al.  Comparison of ongoing compound field potentials in the brains of invertebrates and vertebrates , 1988, Brain Research Reviews.

[17]  Paolo Vitali,et al.  Effects of long-term Donepezil therapy on rCBF of Alzheimer's patients , 2002, Clinical Neurophysiology.

[18]  Erol Başar,et al.  Memory and Brain Dynamics: Oscillations Integrating Attention, Perception, Learning, and Memory , 2004 .

[19]  Erol Başar,et al.  Brain dynamics : progress and perspectives , 1989 .

[20]  Marco Catani,et al.  From hodology to function. , 2007, Brain : a journal of neurology.

[21]  D. O. Walter,et al.  Electroencephalographic spectra and coherence in the diagnosis of Alzheimer's-type and multi-infarct dementia. A pilot study. , 1987, Archives of general psychiatry.

[22]  P. Pietrini,et al.  Altered brain functional connectivity and impaired short-term memory in Alzheimer's disease. , 2001, Brain : a journal of neurology.

[23]  H. Creasey,et al.  Age at onset and pattern of neuropsychological impairment in mild early-stage Alzheimer disease. A study of a community-based population. , 1996, Archives of neurology.

[24]  P Ungan,et al.  Combined dynamics of EEG and evoked potentials. II. Studies of simultaneously recorded EEG-EPograms in the auditory pathway, reticular formation, and hippocampus of the cat brain during sleep. , 1979, Biological cybernetics.

[25]  J. T. Enright,et al.  Are the electroencephalograms mainly rhythmic? Assessment of periodicity in wide-band time series , 2003, Neuroscience.

[26]  K. Blennow,et al.  Synaptic Pathology in Alzheimer’s Disease , 1997 .

[27]  M. Weiner,et al.  Reduced hippocampal functional connectivity in Alzheimer disease. , 2007, Archives of neurology.

[28]  C C Wood,et al.  On the neural origin of P300 in man. , 1980, Progress in brain research.

[29]  M. Rowan,et al.  Memory-related EEG power and coherence reductions in mild Alzheimer's disease. , 2003, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[30]  T. Gasser,et al.  EEG coherence in Alzheimer disease. , 1994, Electroencephalography and clinical neurophysiology.

[31]  Christoph Braun,et al.  Coherence of gamma-band EEG activity as a basis for associative learning , 1999, Nature.

[32]  M Schürmann,et al.  Delta responses and cognitive processing: single-trial evaluations of human visual P300. , 2001, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[33]  W. Klimesch.  Brain Function and Oscillations, Vol. II: Integrative Brain Function. Neurophysiology and Cognitive Processes, edited by Erol Basar , 1999, Trends in Cognitive Sciences.

[34]  E. Ba§ar,et al.  EEG-Brain dynamics: Relation between EEG and brain evoked potentials , 1982 .

[35]  P Ungan,et al.  Combined dynamics of EEG and evoked potentials , 1979, Biological Cybernetics.

[36]  F. H. Lopes da Silva,et al.  Relative contributions of intracortical and thalamo-cortical processes in the generation of alpha rhythms, revealed by partial coherence analysis. , 1980, Electroencephalography and clinical neurophysiology.

[37]  Z. Jiang,et al.  Abnormal cortical functional connections in Alzheimer's disease: analysis of inter- and intra-hemispheric EEG coherence. , 2005, Journal of Zhejiang University. Science. B.

[38]  Tamer Demiralp,et al.  Electroencephalogram alpha (8–15 Hz) responses to visual stimuli in cat cortex, thalamus, and hippocampus: a distributed alpha network? , 2000, Neuroscience Letters.

[39]  Dr. Robert Miller.  Cortico-Hippocampal Interplay and the Representation of Contexts in the Brain , 1991, Studies of Brain Function.

[40]  M. Folstein,et al.  Clinical diagnosis of Alzheimer's disease , 1984, Neurology.

[41]  C. C. Wood,et al.  Scalp distributions of event-related potentials: an ambiguity associated with analysis of variance models. , 1985, Electroencephalography and clinical neurophysiology.

[42]  J. G. van Dijk,et al.  EEG correlates in the spectrum of cognitive decline , 2007, Clinical Neurophysiology.

[43]  R. Verleger,et al.  Reduction of P3b in patients with temporo-parietal lesions. , 1994, Brain research. Cognitive brain research.

[44]  M Schürmann,et al.  Topological distribution of oddball 'P300' responses. , 2001, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[45]  Annalena Venneri,et al.  Cerebral blood flow and cognitive responses to rivastigmine treatment in Alzheimer's disease , 2002, Neuroreport.

[46]  T. Bullock.  How do brains evolve complexity? An essay. , 2006, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[47]  H. Jasper,et al.  The ten-twenty electrode system of the International Federation. The International Federation of Clinical Neurophysiology. , 1999, Electroencephalography and clinical neurophysiology. Supplement.

[48]  Ian A. Cook,et al.  Reduced EEG coherence in dementia: State or trait marker? , 1994, Biological Psychiatry.

[49]  H. Petsche,et al.  The contribution of the cortical layers to the generation of the EEG: field potential and current source density analyses in the rabbit's visual cortex. , 1982, Electroencephalography and clinical neurophysiology.

[50]  L Carlin,et al.  Neocortical neurofibrillary tangles correlate with dementia severity in Alzheimer's disease. , 1995, Archives of neurology.

[51]  E. Basar,et al.  Event‐related delta oscillatory responses of Alzheimer patients , 2008, European journal of neurology.

[52]  E. Basar,et al.  P300-response: possible psychophysiological correlates in delta and theta frequency channels. A review. , 1992, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[53]  Bernat Kocsis,et al.  Theta synchronization in the limbic system: the role of Gudden's tegmental nuclei , 2001, The European journal of neuroscience.

[54]  Ivo D Dinov,et al.  Metabolic patterns associated with the clinical response to galantamine therapy: a fludeoxyglucose f 18 positron emission tomographic study. , 2005, Archives of neurology.

[55]  K. Blennow,et al.  Synaptic pathology in Alzheimer's disease: Relation to severity of dementia, but not to senile plaques, neurofibrillary tangles, or the ApoE4 allele , 2005, Journal of Neural Transmission.