Biomedical subjects
Publications and source records attributed to V I Pudov.
The Center of Cochlear Implantation at St-Petersburg ENT Research Institute was set up in 1997. For three years of its activity 19 cochlear implantations were made in patients of different age. All of them received Combi 40/40+ implants (Med-El, Austria). Prospects of cochlear implantation and problems of its introduction in Russia are analysed.
Updated models of cochlear implants provide good speech audibility and thus complete rehabilitation of children who have lost hearing after learning speech. All the children who lost hearing before learning speech can hear sounds of normal loudness and orient in sound media by means of cochlear implant. However, they need long-term audio-vocal rehabilitation the results of which depend on the age of the child's operation and hi(her) individual traits. Cochlear implants in children aged under 3 years are most perspective. Russian language methodology including 7 tests and 2 questionnaires is described. It is intended for assessment of audio-vocal development in children with cochlear implants and results of audio-vocal rehabilitation as well as of effectiveness of using cochlear implant in children over 2 years of age. Establishment of centers for cochlear implantation and introduction of cochlear implantation state program are recommended.
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.
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.
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.
The examination of 250 children with neurosensory hypoacusis (NSH) demonstrated a 78% efficacy of endaural phonophoresis with dalargin (DPP) and transcranial electrostimulation (TCE) for improvement of acoustic function in the presence of positive ultrasound prognosis. Rheoencephalography and biochemical tests show that neuropeptides improve cerebral hemodynamics and normalize metabolism. Both DPP and TCE promote normalization of protein spectrum of the serum. In addition, TCE normalizes serum magnesium levels and its renal elimination, while DPP normalizes serum content of cholesterol.
Focused ultrasound with a frequency of 2.5 MHz and amplitude-modulated in the range of audiometric frequencies (125-8000 Hz) was employed to examine 50 normal hearing persons and in complex diagnostics of over 500 patients suffering from sensorineural deafness, otosclerosis, chronic otitis media, and acoustic neurinoma. Typical diagnostic signs of these diseases were revealed. Modulated ultrasound is shown to offer an improved diagnosis of hearing diseases. The results confirm the previous observation that amplitude-modulated ultrasound may excite not only the acoustic receptors but also the acoustic nerve fibres. Possible mechanisms of the stimulating effect of focused modulated ultrasound are discussed.
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The versatile II phi-01 flux-gate magnetic pole locator is intended for detecting and locating ferromagnetic foreign bodies in human tissue. The sensitivity of the device to magnetic field gradient is 4 mOe/cm on a large scale. The device can be used to locate a hypodermic needle at a distance of 50-90 mm, a sewing needle at 60-122 mm, a routine 7.62-mm bullet at 90 mm and a 5.6-mm bullet at 105 mm.
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