From Big Medical Encyclopedia

SURDOTERAPEVTICHESKY EQUIPMENT — the devices intended for development of hearing and the speech in hearing-impaired and deaf people.

Long since for strengthening of a sound at relative deafness used special horns, loud-hailers, acoustical pipes, to-rye allowed to concentrate sound vibrations and to transfer them to an ear of hearing-impaired. At the end of 19 century as generators of a sound for a research of the remains of hearing tuning forks, Urbanchich's harmonic were offered (see. Surdomutism ), kinezifon Maurice. In process of development of physics and it undressed — acoustics (see) the sound-amplifying devices based on use of electrical energy were developed. With their help modeling of a source of sounds of various frequency and the choice of required strengthening of a signal became possible. In 70 — 80

20 century thanks to achievements of radio electronics, physiological acoustics, cybernetics more perfect electro-acoustic devices were created — hearing aids (see), audiometers (see. Audiometriya ), the special tape recorders, electrophones and acoustical exercise machines which found broad application for development of hearing and the speech at deafness (see) and relative deafness (see).

Acoustical exercise machines represent the difficult devices which are turning on the microphone (one or two), the amplifier of audibles signal (one-or two-channel) with regulators of level of an output signal, frequency correction and automatic strengthening, headphones for sound transmission on air conductivity and bone vibrators for sound transmission on bone and fabric conductivity. Exercise machines are intended for individual and group occupations. The USSR uses the sound-amplifying equipment to holding individual classes in development of hearing and the speech of deaf children — the «MT Filter» intended for a training of acoustical function, the «Filter-01» intended for a research of acoustical function. The main amplifier with a set of 15 strip and resonant filters in the frequency range of 37 — 10 000 Hz, blocks of the regulator of level of an output signal with the self-adjustment of strengthening, the amplifier of power, two phones and one bone vibrator are included in its package. Depending on a condition of hearing the Filter-01 equipment provides the necessary frequency band of strengthening of audibles signal, their giving separately in each ear or at the same time in both ears.

The equipment can be used also to holding group occupations. In this case it is in addition completed with 12 amplifiers of power with phones and bone vibrators that provides training along with 12 patients.

For development of the speech at severe forms of relative deafness and deafness use, in addition to the listed devices, special devices, to-rye can carry out frequency transfer of a speech range from one zone in ANOTHER - E.g., sounds of a high-frequency spectral range (2000 — 8000 Hz) which are usually not perceived by deafs can be transferred to the low-frequency area (250 — 500 Hz), perception to-rykh at deafs it is often kept. Other devices — chastotnopolosny voice coders, the strip SUVAG-1 and SUVAG-P amplifiers developed in Yugoslavia also can be carried to this group of devices (Guberina, 1961). Special group C. and. make the devices of the so-called visible speech containing the special screen, in particular devices of domestic production «I-2», «I-2M», «VIR-6A», «VIR-6B». The speech of the teacher and answers of the trainee are fixed on the screen of the device in the form of various curves specific to the corresponding audibles signal that allows the patient to control visually correctness of the speech, to try to obtain proofreading of a pronunciation.

Bibliography: M. M Efruss. Hearing aids and audiometers, M., 1975.

V. G. Bazarov, B. S. Moroz.