EEG power spectrum typical of vascular dementia in a subgroup of Alzheimer patients.

A statistical comparative study was carried out between two subgroups of patients with dementia, i.e. 22 with Alzheimer's dementia (AD, 44% of the entire Alzheimer group examined) and 36 with vascular dementia (VaD, 97% of the entire vascular group). The selection of the two subgroups was based on a similar EEG spectral profile in the rest eyes closed condition: a great increase in low frequency powers and a dominant activity in the 6.5-12 Hz band. The aim was to identify any possible difference between the two groups analysing the spectral descriptors, of the two conditions eyes closed and open, the demographic figures and the mental deterioration scores. The results are as follows: (i) the spectral profiles and their numerical descriptors of the AD subgroup patients are not distinguishable from the same parametric figures of the VaD patients; (ii) the spectral analysis becomes useful in differentiating the two types of dementia when a dynamic EEG is processed, i.e. the power ratio of recordings during eyes closed and open; (iii) a more severe mental deterioration, especially in attention and spatial and temporal orientation was found in the AD group as compared to the VaD. The findings are explained in the light of the changes in neural mechanisms which underlie both the alpha and slow rhythms.

[1]  H. Chui,et al.  Clinical subtypes of dementia of the Alzheimer type , 1985, Neurology.

[2]  E. John,et al.  Developmental equations for the electroencephalogram. , 1980, Science.

[3]  F. L. D. Silva,et al.  Basic mechanisms of cerebral rhythmic activities , 1990 .

[4]  T. Gasser,et al.  Transformations towards the normal distribution of broad band spectral parameters of the EEG. , 1982, Electroencephalography and clinical neurophysiology.

[5]  H. Soininen,et al.  EEG findings in senile dementia and normal aging , 1982, Acta neurologica Scandinavica.

[6]  T. Erkinjuntti,et al.  CT in the differential diagnosis between Alzheimer's disease and vascular dementia , 1987, Acta neurologica Scandinavica.

[7]  T. Tatemichi,et al.  How acute brain failure becomes chronic , 1990, Neurology.

[8]  B. Seltzer,et al.  A comparison of clinical features in early- and late-onset primary degenerative dementia. One entity or two? , 1983, Archives of neurology.

[9]  D Giannitrapani,et al.  The EEG spectra of Alzheimer's disease. , 1991, International journal of psychophysiology : official journal of the International Organization of Psychophysiology.

[10]  G. Buzsáki,et al.  The cholinergic system and EEG slow waves. , 1991, Electroencephalography and clinical neurophysiology.

[11]  B. Oken,et al.  Short-term variability in EEG frequency analysis. , 1985, Electroencephalography and clinical neurophysiology.

[12]  N L Foster,et al.  Towards a behavioral typology of Alzheimer's patients. , 1986, Journal of clinical and experimental neuropsychology.

[13]  K. Blennow,et al.  Pathogenetic basis of vascular dementia. , 1991, Alzheimer Disease and Associated Disorders.

[14]  B. Reisberg,et al.  The Global Deterioration Scale for assessment of primary degenerative dementia. , 1982, The American journal of psychiatry.

[15]  Gregory A. Miller,et al.  The linked-reference issue in EEG and ERP recording. , 1991 .

[16]  S. M. Sumi,et al.  Phenotypic heterogeneity in familial alzheimer's disease: A study of 24 kindreds , 1989, Annals of neurology.

[17]  M J Campbell,et al.  Laminar and regional distributions of neurofibrillary tangles and neuritic plaques in Alzheimer's disease: a quantitative study of visual and auditory cortices , 1987, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[18]  J. Blass.  Pathophysiology of the Alzheimer's syndrome , 1993 .

[19]  L. Iversen,et al.  Age and histopathologic heterogeneity in Alzheimer's disease. Evidence for subtypes. , 1987, Archives of general psychiatry.

[20]  D O Walter,et al.  Changes in brain functional connectivity in Alzheimer-type and multi-infarct dementia. , 1992, Brain : a journal of neurology.

[21]  H. Soininen,et al.  Longitudinal EEG spectral analysis in early stage of Alzheimer's disease. , 1989, Electroencephalography and clinical neurophysiology.

[22]  Arnold B. Scheibel,et al.  The Biological Substrates of Alzheimer's Disease , 1986 .

[23]  Janice E. Knoefel,et al.  Clinical neurology of aging , 1985 .

[24]  J. Coyle,et al.  Alzheimer's disease and senile dementia: loss of neurons in the basal forebrain. , 1982, Science.

[25]  J. Weber,et al.  Genetic linkage evidence for a familial Alzheimer's disease locus on chromosome 14. , 1992, Science.

[26]  F. Angeleri,et al.  Effects of chronic thalamic lesions on the electrical activity of the neocortex and sleep , 1969 .

[27]  J. Bendat,et al.  Random Data: Analysis and Measurement Procedures , 1971 .

[28]  S. Folstein,et al.  "Mini-mental state". A practical method for grading the cognitive state of patients for the clinician. , 1975, Journal of psychiatric research.

[29]  C. H. Vanderwolf,et al.  Cholinergic activation of the electrocorticogram: Role of the substantia innominata and effects of atropine and quinuclidinyl benzilate , 1984, Brain Research.

[30]  I. Rainero,et al.  Genetic linkage studies suggest that Alzheimer's disease is not a single homogeneous disorder , 1990, Nature.

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

[32]  E. Mohr,et al.  Heterogeneity in Alzheimer's disease: progression rate segregated by distinct neuropsychological and cerebral metabolic profiles. , 1992, Journal of neurology, neurosurgery, and psychiatry.

[33]  A. Alzheimer.  Uber eine eigenartige Erkrankung der Hirnrinde , 1907 .

[34]  F Angeleri,et al.  EEG spectral analysis in vascular and Alzheimer dementia. , 1995, Electroencephalography and clinical neurophysiology.

[35]  J. Coyle,et al.  Alzheimer disease: Evidence for selective loss of cholinergic neurons in the nucleus basalis , 1981, Annals of neurology.

[36]  J. Morrison,et al.  Quantitative morphology and regional and laminar distributions of senile plaques in Alzheimer's disease , 1985, The Journal of neuroscience : the official journal of the Society for Neuroscience.

[37]  Mario F. Mendez,et al.  Neurobehavioral changes associated with caudate lesions , 1989, Neurology.

[38]  R. Heaton,et al.  Neuropsychologic features of early- and late-onset Alzheimer's disease. , 1986, Archives of neurology.

[39]  R. Mayeux,et al.  Heterogeneity in dementia of the Alzheimer type , 1985, Neurology.

[40]  C. Villardita.  Alzheimer's disease compared with cerebrovascular dementia. Neuropsychological similarities and differences , 1993, Acta Neurologica Scandinavica.

[41]  J. Moossy,et al.  A brain regional analysis of morphologic and cholinergic abnormalities in Alzheimer's disease. , 1989, Archives of neurology.

[42]  J Marshall,et al.  Cerebral blood flow in dementia. , 1975, Archives of neurology.

[43]  N. Foster,et al.  Alzheimer's disease , 1983, Neurology.

[44]  D O Walter,et al.  Regional differences in brain electrical activity in dementia: use of spectral power and spectral ratio measures. , 1993, Electroencephalography and clinical neurophysiology.