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Biomedical subjects

N V Ponomareva

Publications and source records attributed to N V Ponomareva.

18 recordsLinked to original sources
PubMed2003

EEG alterations in subjects at high familial risk for Alzheimer's disease.

Twenty first-order relatives of patients with early-onset Alzheimer's disease (AD; mean age 43.7 +/- 1.3 years), 20 patients with early-onset AD (mean age 65.7 +/- 0.9 years) and age-matched normal controls for the relatives and the patients underwent quantitative EEG (qEEG) examinations. In AD patients, delta and theta relative power values were increased and alpha relative power was decreased compared with normal controls. The AD patients' relatives had normal resting EEG parameters. Under hyperventilation in the AD relatives, synchronous high-voltage delta and theta activity and sharp waves were revealed, theta and delta relative powers were increased and alpha relative power was decreased compared with the resting EEG in the same persons. Moreover, under hyperventilation, the theta and delta relative powers in the EEG of the relatives were higher, and the alpha relative power was lower compared with the EEG of normal controls under the same conditions. It is suggested that the excitotoxic processes and oxidative stress underlie the EEG alterations in the AD patients' relatives and that these alterations may be related to the further AD development.

Adult↗
PubMed2001

[The rate of cerebral energy metabolism: possibilities of its assessment by the electrophysiologic method].

The application of DC-potential method for estimation of the rate of human brain energy metabolism opens new vistas for the development of theoretical and applied aspects of neurophysiology. Theoretically, the close connection of information and energy processes of the brain is essential for gaining an insight into the brain energy-formation unit. In applied physiology, estimation of brain energy metabolism by the DC potential method is useful for studying the relationship of brain energy and memory processes during learning, for estimating the training in sportsmen, for predicting longevity in the elderly. The method reveals stress-induced changes in interhemispheric relationships. In medicine the method may be used to study the pathogenesis of primarily the diseases associated with impaired cerebral circulation and cerebral atrophic processes. Moreover, of particular diagnostic and prognostic value are these methods for drug addicts, as well as for monitoring suggestive therapeutical effects in the treatment of neuroses.

Adaptation, Physiological↗
PubMed1999

[Brain dysfunction in subjects at risk of Alzheimer's disease].

Visual evoked potentials versus flash (VEP) and brain DC-potentials were studied in the first-order relatives of patients (mean age 42.6 +/- 1.6 years) with Alzheimer's disease (AD) and probands (mean age 60.9 +/- 0.9 years) and age-matched healthy controls for the relatives and probands. In the relatives of AD patients, the latencies of N2, P3, N3 components were found to be delayed as compared with the controls. There was a delay in the latencies of the same components in the patients and their relatives, but it was smaller in the relatives of AD patients. The brain DC-potentials were higher in the relatives of AD patients than in the controls. Neurophysiological changes in the relatives of AD patients may be considered to be signs of latent neurodegeneration in the limbicoreticulocortical pathways, which may be associated with the excitotoxic processes and abnormal hyperactivity in the limbicoreticulocortical structures.

Adult↗
PubMed1999

[Analyzing correlation between neurophysiological parameters and level of stress hormone cortisol in aging].

A correlation between the serum levels of the stress hormone cortisole, neurophysiological parameters, and age was examined in 23 elderly healthy examinees (whose mean age was 65.7 +/- 2.1 years). The latency of the components of visual evoked potentials (VEP) was found to progressively increase with age. The individuals having high cortisole levels showed an increase in the latency of late VEP components associated with accelerated ageing and/or with the degenerative changes in the brain limbicoreticulocortical pathways. The DC potential level (DCPL) reflecting the intensity of brain energy expenditures correlated with the content of cortisole. Increased DCPL and longer latency of late VEP components were interrelated. It is suggested that high cortisole level produces a neurotoxic action and promotes accelerated ageing of brain regions having glucocorticoid receptors. Imbalance between the significant intensification of catabolic processes, the rise of energy expenditures and the limited increase in anabolism in elderly age is a course of this process.

Aged↗
PubMed1996

[The neuroimmune relationships during normal aging and in Alzheimer-type dementias].

Relationships between neurophysiological and immune parameters were studied in normal middle-aged and elderly subjects and in patients with dementia of Alzheimer's type (DAT). The rate of such interaction was minimal in normal aging, in DAT neuroimmune relations increased. The correlation between the immune parameters and the characteristics of components of visual evoked potentials and auditory brain-stem responses suggests that in the middle-aged healthy subjects, a primary role in neuroimmune relations belongs to limbicoreticular structures and to the mesencephalon. In normal aging, the influence of limbicoreticular structures on immune structures decreases. In DAT, the modulation of immune processes by limbicoreticular and thalamocortical structures, as well as the pontobulbar part of the brain stem increases. In middle age and in DAT, persons with different functional brain asymmetry (as estimated from electrophysiological criteria) have different lymphocytic functional activities and rates of neuroimmune interactions.

Adult↗
PubMed1995

[Neuroimmune interactions in normal aging and in Alzheimer disease].

The study was undertaken to examine nerve-immune processes and the specific visual and limbic-reticular-cortical systems by analysing visual evoked potentials (VEP), as well as nerve-immune relationships in 21 patients aged 62.2ë1.3 years who had Alzheimer's disease and in 15 healthy individuals of the same age. AD patients were found to have lower lymphocyte count, enhanced proliferative activity of T lymphocytes and to tend to have increased production of interleukin (IL-1) as compared to that in healthy individuals. In AD, latent periods of late EVP components are higher than normal age-specific ones. The relationship between VEP and immunity parameters differ in normal ageing and AD. In health, there is a negative correlation between the latencies of N1, P2, N2 VEP components and the lymphocyte count and between the amplitude of a N1 VEP component and the production of IL-1. There is a prevalent correlation of immune parameters with VEP parameters in the right hemisphere. In AD, the higher proliferative activity of T lymphocytes is associated with more prolonged latent periods of N3 VEP components, suggesting that there are abnormal changes in the limbic-reticular-cortical systems of the brain.

Aging↗
PubMed1994

[The energy aspect of the brain activity in normal aging and in Alzheimer's disease].

In normal aging and Alzheimer's disease, there are regular changes in brain energy homeostasis, which are associated both with the time course of the average level of catabolism and with the intensity rate of catabolic processes by hemispheres. In normal aging, there is generally decrease in the catabolic level estimated by the level of the DC potential. In Alzheimer's disease, the level of catabolism secondarily increases. The findings suggest that there is a causal relationship between the brain energetic homeostasis and the visual information processes. The correlation of energetic and information processes increases with normal and especially pathological aging. The authors' methods enabled them to observe the time course of energy metabolism and to reveal their critical levels. The correction of energetic processes in due time should be useful in preventing atrophic changes in the brain with aging.

Aging↗
PubMed1992

[Longitudinal approaches to the problem of clinical heterogeneity of Alzheimer-type dementia].

A total of 160 patients with Alzheimer-type dementias (ATD), including 84 with Alzheimer's diseases (AD) and 76 with senile dementia (SD), were examined. The initial signs of the disease were analyzed by making a retrospective assessment of informative history data. The prospective follow-up involved clinical, neuropsychological and electrophysiological (EEC mapping, evoked potentials) studies by applying the standardized assessment of results. There was shown to be a set of clinical and paraclinical parameters for the status of ATD patients, indicating a distinct-quantitative and qualitative difference between patients with AD and those with SD and supporting the heterogeneity of ATD.

Aged↗
PubMed1989

[Relation between the changes in evoked and constant potentials of the brain and emotional disorders in Alzheimer's disease].

The visual evoked potentials (VEP), brain DC potential (DP) mapping and emotional disorders were comparatively evaluated in patients with Alzheimer's disease (AD) and age-matched healthy individuals. In AD, the severity of emotional disorders correlated with the reduction of VEP late components P 4 N 4. In patients with frequent affect oscillations, the amplitude of N 3 component of the VEP and its variability was higher than in patients with rare undulations of the emotional state. In AD patients the DP levels were increased as compared to normal levels in all the brain sites investigated. The degree of emotional disorders in AD patients positively correlated with frontal DP levels. The rise in frontal DP levels and decrease in late VEP components were interrelated in AD patients.

Action Potentials↗
PubMed1989

[The relationship of the electrical reactions of the brain to lipid peroxidation processes in pathological aging].

The content of breathing air pentane as in vivo index of lipid peroxidation and electrophysiological parameters (visual evoked potentials and direct current (DC) potential level) of healthy volunteers and patients with senile dementia and Alzheimer's disease following weak stress sound influence were investigated. Unlike healthy subjects correlation between stress-induced changes of pentane level and electrophysiological parameters for patients with psychopathology was shown.

Acoustic Stimulation↗
PubMedDate not supplied

Interdependance of the level of the steady potential of the brain and visual evoked potentials in human aging: the norm and Alzheimer's disease.

The interrelationships between the amplitude-temporal parameters of the visual evoked potential (VEP) and of the level of the steady potential (LSP) of the brain in healthy middle-aged and elderly people and in Alzheimer's disease patients. The existence of a statistically significant correlation between the LSP and the amplitude-temporal characteristics of the VEP. The interrelationship is intensified both during aging in the norm and especially in Alzheimer's disease patients. The most stable positive correlation exists between the local LSP and in the occipital region and the amplitudes of the N1 and P2 components of the VEP.

Adult↗
PubMedDate not supplied

Possible neurophysiological markers of genetic predisposition to Alzheimer's disease.

Visual-evoked potentials (VEP) to a flash were studied in the first-order relatives of patients with Alzheimer's disease (AD) (mean age 38.2 +/- 2.6 years) in comparison with the patients (mean age 61.9 +/- 1.4 years) and age-matched normal controls. It was found that in the relatives of AD patients the latencies of N2, P3, N3 components were delayed compared with the age-matched normal controls. The delay in the latencies of the patients and their relatives concerned the same components but was smaller in the relatives of AD patients. The amplitude of the P2, N2 components was increased in the latter. The neurophysiological alteration in AD patients' relatives may be considered as signs of a latent neurodegeneration in limbico-reticulo-cortical pathways, which may be connected to the pathological hyperactivity of limbico-reticulo-cortical structures.

Adult↗
PubMedDate not supplied

[The dynamics of the direct current potentials of the brain during sustained attention in 10-11-year-old children].

The dynamics of direct current potentials of the brain was studied in 10-11-year-old children during sustained attention to successive presentation of series of Shulte tables. Children were examined twice: before and after the series of training to fast reading. A gradual increase in the level of direct current potentials during sustained attention was observed. The increase was more pronounced in children with excessive than in children with moderate reactions to the loading. After the series of training to fast reading, the increase in the level of direct current potentials was reduced in both groups. This aftertraining neurophysiological phenomenon was combined with a transformation of psychophysiological characteristics: a decrease in the time of viewing of Shulte tables and increase in the speed of reading. It is suggested that the shifts of direct current potentials reflects the dynamics of intensity of the cerebral energy metabolism.

Attention↗
PubMedDate not supplied

[The interrelation of the level of the brain DC potential and visual evoked potentials during human aging: the norm and Alzheimer's disease].

Correlation between DC-potential level and visual evoked potentials (VEP) was investigated in normal subjects of the middle and old age and the patients with Alzheimer's disease. Significant correlation between the DC-potential level and the amplitudes and latencies of different components of VEP was found. The correlation was intensified during ageing mostly in patients. More stable positive correlation existed between local DC-potential level recorded in the occipital area of the head and the amplitude of the components N1 and P2 of VEP.

Adult↗