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Biomedical subjects

L I Peresleni

Publications and source records attributed to L I Peresleni.

16 recordsLinked to original sources
PubMed1996

[A clinico-physiological and psychological-pedagogical analysis of the structure of the defect in cognitive activity in 3 cases of different forms of speech pathology].

Clinical (neurological), neurophysiological (EEG) and psychological examinations were carried out in 3 children with general speech defects. These children represented 3 main groups with speech disturbances: with speech defects which may be logopedically corrected, with speech defect and intact intellectual ability, with considerable disturbances of speech and cognitive functions. The peculiarities of cognitive disturbances were determined in each group. They were manifested in the form of alterations either of basic EEG or of EEG response to different stimuli as well as in psychological profile structure.

Child↗
PubMed1989

[Characteristics of the conceptual and logical thinking of younger schoolchildren from the aspect of diagnosing intellectual impairment].

To improve reliability of mental retardation (MR) diagnosis, psychiatrists should employ techniques providing assessment of various psychic functions including conceptual thinking. Such a technique is presented in the paper along with four verbal subtests, relevant examination procedure, processing of the data obtained, evaluation of the successful task performance. The examination has covered a representative sample of an ordinary school pupils attending forms 1 and 2 as well as MR children. Quantitative criteria of MR determination have been established. The validity of the technique inclusion into the standard complex aimed at detecting the underlying factor in the defect is described.

Age Factors↗
PubMed1986

[Diagnosis and clinical picture of oligophrenia among students with cerebral palsy].

A clinico-psychological examination covered 112 children aged 7-9 years with cerebral paralysis. The authors consider the diagnosis of intellectual disorders using traditional clinico-psychological techniques and an original technique of prediction ("Ugadaika" and Raven's matrices). the latter two methods, when combined with clinical examination, were shown to be highly informative in diagnosing oligophrenia in junior schoolchildren. Characteristics of oligophrenia in different forms of infantile cerebral paralysis are described.

Cerebral Palsy↗
PubMedDate not supplied

Neurophysiological mechanisms of the attention disturbance in children with learning difficulties.

The features of orientation reaction (OR) and the background EEG were investigated with the purpose of studying the neurophysiological mechanisms of the disturbance of voluntary attention in children aged 6.5-9 years with learning difficulties caused by delayed mental development (DMD). A decrease in the expressivity of components of the OR as compared with the norm, discovered in a situation of involuntary attention against a background of insufficiently developed cortical rhythmicity in the alpha range, was compensated for given an increase in the significance of the stimuli. These facts support the hypothesis of a deficit in regulatory corticofugal influences in children with DMD. The inadequacy of the engagement of central regions of the cortex characteristic of children with DMD in the realization of OR in a situation of directed attention can be regarded as a reflection of disturbances of the integrative activity of the brain.

Attention↗
PubMedDate not supplied

[The characteristics of probabilistic prognosis and of the orienting reaction in children with learning difficulties].

Middle-aged school-children were examined with learning disabilities, differentiated by the parameters of probabilistic prognosis in two subgroups: with disturbances of attention (1) and memory (2). The first subgroup differed from the norm by intensified reaction of desynchronization of the projection areas of the cortex to irrelevant stimuli. Relevant information evoked an increase of activation of the associative zones, less expressed than in the norm. In the second subgroup a weak involvement of associative cortical areas in the reaction of desynchronization to relevant stimuli correlated with insufficient formation of alpha 2-rhythm and high frequency of meeting the signs of dysfunction of mesodiencephalic brain structure. The results are discussed in the aspect of the role of neurophysiological mechanisms of regulation and trace fixation for the formation of the integrative brain activity in the ontogenesis.

Attention↗
PubMedDate not supplied

[Neurophysiologic mechanisms of attention disorder in children with learning difficulties].

In order to study neurophysiological mechanisms of the disturbance of voluntary attention in children of 6.5-9 years old, which had difficulties in learning caused by a delay of psychic development (DPD), characteristics were studied of electrocortical and vegetative components of orienting reaction (OR) to indifferent and relevant stimuli and also of background EEG. A decrease of OR components revealed in situation of involuntary attention against the background of insufficiently formed cortical rhythm of alpha-range, as compared with the norm, is compensated at the increase of stimuli significance by verbal instruction. These facts confirm the supposition about deficit of regulating influences of the frontal cortical areas on the ascending activating system in children with difficulties in learning. Deficiency of the involvement of the central cortical areas in OR realization, typical of the children with DPD in a situation of voluntary directed attention, can be considered as reflection of disturbances of integrative brain activity.

Acoustic Stimulation↗
PubMedDate not supplied

[Reorganization of human evoked potentials during automatization of motor reactions].

Evoked electrocortical activity appearing during rhythmic stimulation and its correlation with the level of expectancy of the signal next in turn (expressed in values of reaction time), were studied in nine grown up subjects. Reorganization of auditory evoked potentials (EPs), mostly expressed during reactions preceding the stimulus or coinciding with it occurs at motor responses to rhythmical stimuli. The character of correlation between EPs and perception is satisfactorily explained by a cyclic model of the sensory information processing. Adaptive behaviour is provided by the cyclic processes promoting engrams formation and adequate pretuning to probable events.

Acoustic Stimulation↗
PubMedDate not supplied

[Signs of pre-tuning in the dynamics of evoked activity and reaction time in children].

Somatosensory evoked potentials (EP) and reaction time (RT) in response to tactile signals proceeding in a fixed or random sequences were simultaneously recorded in ten to eleven year old children. The connection between the dynamics of sliding means of both parameters was analysed. It was found that a reduction of RT correlated with stabilization of electrical cortical responses. The change in the signals alternation produced an interrelated lengthening of RT and dispersion of EP amplitudes, particularly pronounced for its early phases. Distinct interconnection between RT shortening and reduction of dispersions of EP components reflects the organization of a representative system, which provides for the enhancement of the level of pre-tuning (readiness) for perception of the highly probable sequence of the signals. Hypothesis of reflection of reverberation processes in the EP waves permits a satisfactory explanation of EP variability in signals recognition.

Afferent Pathways↗
PubMedDate not supplied

[Relationship between evoked potential parameters and perception].

Somatosensory EPs and reaction time were recorded simultaneously in 7-8 years old children when they solved perceptual tasks with 4 levels of complexity. The obtained data confirm the studies, suggesting the lack of connection between perceptual processes and amplitude-temporal parameters of early and late EP components in the projection cortical area. The method of recording summary evoked activity, while allowing to determine the degree of involvement of nervous elements or structures in the response to sensory signals, does not reveal spatial-temporary patterns of impulse activity in the cortical and cortical-subcortical-cortical loops providing for perception. The idea that dynamics of EP parameters produced by multiple sensory signals reflects the process of entry into memory and read out of stored information may be efficient for the understanding of mechanisms underlying higher cortical functions.

Child↗
PubMedDate not supplied

[Phenomenon of masking in the reproduction of tactile signals].

The study of central masking and of its mechanisms is of interest in connection with the problem of transmitting information through the cutaneous communication channel. The subjects were children aged from seven to eight and from thirteen to fourteen with normal hearing, as well as deaf children. Latency and errors to localizing signals from isolated or paired action of four vibrators were determined in three series of experiments, using three, six and ten altenatives. A dependence of the precision of localization on the amount of information has been found: deteriorated identification is more pronounced in junior schoolchildren and in those with abnormal development. Matrices of the errors provide material for plottingildterial for plotting charts of convergence of afferent inputs. To elucidate the mechanisms of central masking, a comparison was made between the results of psychophysical and microphysiological experiments. Data analysis leads to the conslusion that the phenomenon of masking is determined by two factors: (1) the nature of the convergence of afferent inputs on the neuronal brain structures; (2) the level of formation of psychic operations which provide for singling out distinctive characteristics of signals, with subsequent decision regarding the certain class to which they belong, and with their recognition.

Adolescent↗