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Biomedical subjects

S M Petrov

Publications and source records attributed to S M Petrov.

At least 19 recordsLinked to original sources
PubMed2005

[Speech perception learning in patients with cochlear implants].

A model of speech apprehensibility of postlingual patients after cochlear implantation has been developed. The study of filtrated speech comprehension by persons with normal hearing has used speech material in three 50 Hz spectral bands. The central frequencies were selected by tonotopics of the basilar cochlear membrane. Characteristics of speech comprehension and apprehensibility by recipients of cochlear implants are demonstrated. The model reveals problems of acoustic comprehension facing the implanted patients and shows importance of learning and personality features of the implanted patients for early rehabilitation.

Cochlear Implantation↗
PubMed2003

[Electrical testing of candidates for cochlear implantation].

The results of electrotesting and their possible value in selection of candidates for cochlear implantation are discussed. The threshold curve shape is explained. Basing on this explanation correlations between pre- and postoperative results obtained by different authors are discussed. Pure tone audiogram is thought to be a reliable predictor of the eighth nerve survival. The results of threshold audiometry are considered. Change of tonotopical organization in the recipients with neurosensory hypoacusis gives additional information about cochlear nerve condition.

Audiometry, Pure-Tone↗
PubMed2002

[Initial information on adjustment of speech processor of the cochlear implant].

Adjustment of a speech processor of the cochlear implant is the first procedure in rehabilitation of patients after cochlear implantation. Influence of setting understated and overstated threshold levels of current perception on processing of a speech signal was studied. The results of the study show that only precise estimation of current perception threshold and comfortable loudness allow transmitting maximal acoustic information for each patient.

Cochlear Implantation↗
PubMed2002

[Some aspects of adjustment of a speech processor of the cochlear implants Combi-40/40+ and Tempo+].

The author describes how to perform the first switching on the speech processors (SP) and subsequent adjustment of cochlear implant SP. These SP Combi-40/40+ and Tempo+ were adjusted in 25 patients aged 2 to 27 years who lost hearing at the age 0-26 years. By problems arising at the first switching on and adjustment, all the implanted patients can be divided into three groups: postlingual--those who lost hearing after speech establishment; perilingual--those who lost hearing step by step starting from hypoacusis; prelingual--those who had lost hearing before they could speak. How to adjust SP in each group of the above patients is described.

Adolescent↗
PubMed2000

[Some aspects of pure tone audiometry].

Masking procedure during hearing threshold measurement in air conduction mode, order of investigation of bone conduction perception are proposed. Range of application of broad band and narrow band masking noises is considered.

Adult↗
PubMed2000

[Band filtration of the speech signal: speech perception in health status and in sensorineural hearing loss].

We made band speech filtration by dividing the spectrum into the frequency bands 50, 100, 200, 500 and 1000 Hz with following removal of the even or odd bands. We found that audibility of speech in all the examinees with normal hearing was 100% irrespective of the band width and composition of the speech signal (a total of the even or odd bands). Audibility of speech composed of odd bands 100 Hz width improved by 4 to 16% in patients with neurosensory hypoacusis.

Audiometry, Pure-Tone↗
PubMed1999

[On the modeling of acoustic perception in patients with implants].

Four laws of the spectrum division into frequency bands programmed into the implant Combi-40 were applied. After processing of the speech tables using specially developed program, frequency-restricted speech signal was obtained. It contained 8 bands covering 50 Hz each. These were central frequencies of band filters of the speech processor. Training was needed for all examinees with normal hearing to master a new speech picture after which words differentiation reached 100% in all the four variants of the spectrum division. Thus, excess of speech in terms of frequency representation is more than 92.3%. Parallels are given between speech perception of patients with implants and perception of speech changed according to the above program by subjects with normal hearing.

Cochlear Implantation↗
PubMed1998

[Problem of cochlear implantation: brief introduction].

The only method of hearing rehabilitation for patients with severe hypoacusis and peripheral deafness is cochlear implantation consisting of insertion of electrodes into the scala tympani and direct electric impulse stimulation of the auditory nerve adjusted to the input acoustic signal. Only few such operations have been performed in this country. Much effort should be devoted to training of specialists and advocating this method among practitioners.

Cochlear Implantation↗
PubMed1998

[The characteristics of hearing perception in light of the problem of rehabilitating patients who have undergone implantation].

There are significant differences in hearing perception of normal and cochlear implanted individuals. Though the implant processor changes time and frequency characteristics of the speech signal, some implanted patients are able to adapt to their new perception and to return to full understanding of live speech. We make the attempt to understand how the implanted patients percept new picture of speech and suggest the plan of rehabilitation for subjects who lost hearing early.

Auditory Perception↗
PubMed1997

[Interpretation of the results of various audiological tests in patients with neurinoma of the VIII nerve].

The literature gives controversial data on audiological examination of patients suffering from neurinoma of the VIII nerve. They vary from normal to sharply abnormal. Mechanisms of clinical variations of this disease are also unclear. The author makes an attempt to explain the results of some audiological tests basing on the original model of perception and interpretation of the stimulus intensity.

Cranial Nerve Neoplasms↗
PubMedDate not supplied

[Use of shortened latent auditory evoked potentials in the evaluation of the effectiveness of hearing aids].

An electrophysiological correlate of an effective enhancement of hearing aids (HA) can be emergence of a well differentiated V wave in three BERA tracings. The presence or absence of an unstable V wave is indicative of an inadequate HA enhancement; when comfortable loudness is exceeded, high-amplitude V wave with a shortened latent period (LP) as well as other waves that do not belong to BERA are recorded. An average LP value of V wave for different types of hypoacusis has been determined when the HA output is set at comfortable loudness. Other factors that have an impact on the V wave LP are also considered.

Adult↗