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Biomedical subjects

L Tsaneva

Publications and source records attributed to L Tsaneva.

At least 19 recordsLinked to original sources
PubMed2004

Correlations between certain hearing changes and vegetative balance in miners.

This study responds to the priorities of the National Health Strategy aimed at control and mitigation of the hazardous effects of the workplace factors on cardio-vascular diseases of people in active working age from the branch "Mining industry". The aim of this work is to study the vegetative balance (by analysis of heart rate variability--AHRV) and the correlations with the state of miners' hearing functions. Sixty eight miners (diggers and mate-diggers) from mining industry were studied. This paper treats the results of AHRV examination of 25 miners who have no major and additional causes, leading to hearing injury--traumas, other diseases, medicines, etc. The analysis of heart rate variability was made by computer analysis of heart rate and variability. Standard ECG electrodes at bi-polar breast lead-off were used for recording ECG signals. The echo-cardiographic signal was converted by an ECG converter board into epochs of cardiac events (R-R intervals) for 10 minutes. The principal indices of heart rate variability were analysed. The obtained results provide the ground for further comprehensive studies on different workers contingents from other industries in order to detect workers with initial changes in the hearing analyser and to establish the corresponding pathogenetically based registration, monitoring, and treatment system. The studies conducted for monitoring the dynamic of vegetative equilibrium reflect the degree of disturbed heterostasis by chronically manifested sympatic activity in miners, diagnosed by AHRV indices. The revealed significant relationships between hearing changes and AHRV indices prove the presence of an extra-aural paraprofessional effect and statistically significant relations with the changes in the critical organ. The revealed highly significant correlations between AHRV indices and hearing show a significant relationship between the physiological vegetative level (assessed by AHRV) and the hearing status at chronic exposure to work-related stress factors in miners. The chronic sympathicotonia is an additional pathogenic factor (besides acoustic stress) manifested by spastic changes in the microcirculation of the cochlear neuroreceptor elements.

Adult↗
PubMed2003

Masking effect of music upon oral information processing.

The masking effect of three types of music and white masking noise upon special audiometric tests was determined in laboratory c. The stimulus-noise (S/N) ratio was found to be the most considerable factor influencing oral information processing in spite of the type of music or noise used as a masking agent. All types of music (modern, classic or modern music records in backwards order) showed no significant differences in masking being in the same way stronger maskers as white noise. Some conclusions are made concerning hygienic and ergonomic aspects of the problem.

Audiometry, Speech↗
PubMed2002

The "cost" of silence.

Changes in the organism of control desk operators caused by difficulties faced during productionally relevant speech information processing under conditions of intense occupational noise, represent the psychophysiological "cost" of noise masking. Its presence attests to difficulties in processing before deterioration of the quality of the latter while its quantitative characterisation correlates positively with the degree of the masking effect of noise and with the neuropsychic stress of this particular type of work. For this reason an attempt is made to demonstrate noise masking under laboratory conditions with it approximate quantitative evaluation at two signal/noise ratios- +15 and The statistically significant differences between the values of pulse rate, plethysmography and vocal exertion at the above ratios point to both its presence, and to the necessity to be considered when assessing the occupational burden and standardisation of noise intensity in productions associated with speech signals.

Bulgaria↗
PubMed1998

[The evaluation of indices of noise impact on humans].

Due to noise, information processing changes, rate and quality of work deteriorate. Laboratory experiments prove noise exposure to increase dyastolic blood pressure. Multiple factors of occupational environment induce significant individual variability of blood pressure, putting a little value to blood pressure changes. Functional changes of visual analyzer are expressed by reliable increase in eye electrical sensitivity threshold and by lower acuity of vision. Changes in oculomotory coordination are expressed by longer performance time and higher error rate. The authors discuss possible use of psychophysiologic methods to evaluate influence of noise on humans.

Humans↗
PubMed1997

Changes in some psychophysiological parameters in speech information processing under masking noise effect.

The aim of the present work was to study the influence of masking broad-band (white), impulse and interrupted noise with intensities LAeq 60 and 90 dB(A) on the execution of some psychophysiological tasks. The following parameters were studied: pulse frequency and variation, breathing frequency and variation, vascular tone etc. The psychological tasks model different parts of the operators' activity and include: conduction of mathematical calculations at datum speed; test related to the information processing; complex optional task supplied by Piorkovski's device. After statistical processing of results by Student-Fischer's t test and monofactor dispersion analysis it was established that the masking noise effect was more strongly expressed in the execution of psychophysiological tasks connected with the main memory. Of all tested physiological parameters the changes in the peripheral circulation, expressed in elevated vascular tone of peripheral blood vessels, were the most significant.

Adult↗
PubMed1996

[The hygienic ergonomic protection of speech communication over time].

In the course of the experimental laboratory studies it was found out a significant impairment of the communication following a 2-hour processing of speech signals in conditions of masking noise. In order to diminish the auditory exhaustion in impeded communication the authors created physiologically grounded model of the working and resting regime in accordance to the experimental data, which require the including of two breaks in the first half of the working day, i.e. after a two hour exposition to masking noise. The minimal duration of the break at the end of the second hour (according to the experimental data) must be not less than 10 minutes in order to reach the initial or near to it speech communication. The time of the second break may coincide with the regulated lunch-time. The created working and resting regime was approbated in working conditions at DF "Kremikovtsi". It was found out that following the introduction of the physiological regime of work and rest, the auditory exhaustion decreased which was expressed in lowering of the rate of tone-intensity steps.

Adaptation, Physiological↗
PubMed1995

[The effect of different masking noises on psychophysiological tasks].

This paper describes experimental investigations aimed at clarifying the influence of wide-range (white), pulsed and interrupted noise with intensities Lequ 60 and 90 dB (A) on some psychophysiologic characteristics of problem solving. Physiologic indicators were recorded: pulse rate and variance, breathing rate and variance, vascular tone, ets. Psychologic problems to be solved modeled various features of operator activities, including: performing mathematical computations at a given rate; a test involving information processing; a compound option problem offered by Piotkovski's apparatus. Statistical data treatment (t-test of Student and Fisher, and monofactorial dispersion analysis) indicated the masking effect of noise to be more marked in dealing with psychophysiologic problems relating to operative memory. From the physiologic parameters tested, most informative proved to be the changes occurring in peripheral circulation, notably, the rise in vascular tone to peripheral vessels.

Adolescent↗
PubMed1995

[The effect of different types of music on the perception of speech information].

Under experimental conditions, the masking effect of three types of music and of "white" masking noise was studied using a special speech-audiometric test (L. Tsaneva 1978, 1993). The signal-to-noise relation was found to be the most significant factor affecting spoken information perception, regardless of the type of music used as masking agent (level of correlation coefficients, jR = 0.89). The types of music used (modern, classical, playback) showed no appreciable differences in masking, remaining at the same time stronger masking factors compared to "white" noise. Conclusions were made as to hygienic-ergonomic aspects to be considered for intensity of musical programs in conforming with pertinent standards.

Audiometry, Speech↗
PubMed1994

[The mapping of the masking effect of noise in relation to the adaptive potentials of the auditory analyzer for speech communication].

The work considers the problem of ergonomic evaluation on the abilities of the auditory analyzer for speech information processing, depending on the zones of masking effect of noise and the rate of speech communication. Significant increase the loss of speech communication with increase in the intensity of the masking effect of noise (from 21.33% at L eq. 40 dB to 96% at L eq. 90 and above 90 dB/A). The speech communication is determined on scale in 4 zones, depending on the qualitative-quantitative criteria of the speech communication processing [I, II, III and IV zones]. Of point of view of ensuring the necessary conditions for perception of the speech communication is confirmed the correctness of the norm for masking noise L eq. 65 dB/A/, which guarantees a good speech communication. Equivalent levels of the masking noise about or equal to L eq. dB/A/ guarantee a satisfactory speech communication in the command desks. When the intensities of the masking noise are above the norms they are of specific importance, as they fall into the unaccepted (bad) zone, of the auditory perception of speech communication.

Adaptation, Physiological↗
PubMed1993

[The discomfort threshold studied in operators at the control consoles in automated production with a view to its use in job selection].

The results from the investigation of the threshold of discomfort in 385 operators from firm "Kremikovtsi" are discussed. The most expressed changes are found in operators with increased tonal auditory threshold up to 45 and above 50 dB, in high confidential probability. The observed changes in the threshold of discomfort are classified into 3 groups: 1). Raised tonal auditory threshold (up to 30 dB) without decrease in the threshold of discomfort; 2). Decreased threshold of discomfort (with about 15-20 dB) in raised tonal auditory threshold (up to 45 dB); 3). Decreased threshold of discomfort on the background of raised (above 50 dB) tonal auditory threshold. On 4 figures are represented audiograms, illustrating the state of tonal auditory threshold, the field of hearing and the threshold of discomfort. The field of hearing of the operators from the III and IV groups is narrowed, and in the latter also deformed. The explanation of this pathophysiological phenomenon is related to the increased effect of the sound irritation and the presence of recruitment phenomenon with possible engagement of the central end of the auditory analyser. It is underlined, that the threshold of discomfort is sensitive index for the state of the individual norms of each operator for the speech-sound-noise discomfort.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗