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PHYSIOLOGY AND METHODS OF STUDY OF HEARING

The auditory system provides a sound wave, its conversion into nerve impulses, their transmission to the auditory centers, analysis and integration of sound information. The frequency, strength and timbre of sounds are differentiated. With the help of speech, people communicate. Thanks to auditory memory, you can find out whether a voice belongs to a specific person, animal or sound - an object. The auditory system provides tuning of the middle ear and sensitive cells of the spiral organ to sounds of a certain strength and frequency. With strong sounds, it, to a certain extent, lowers sound conduction, performing a protective function. With the help of the hearing organ, with a sudden strong sound, protective and indicative reactions of the body are realized: blinking (ankylosing spondylitis reflex), narrowing of the pupil (cochleopupillary reflex Shurygin), turning the head towards the sound source.

An adequate irritant to the organ of hearing is sound, which is the oscillatory movement of particles of an elastic medium propagating in the form of waves in air, liquids and solids.

Sounds of the same frequency or clear sounds (tones of a tuning fork, audiometer) are rare in nature. They are characterized by sinusoidal, that is, periodic oscillations. More often we are surrounded by complex sounds and noises with overtones and aperiodic vibrations.

The parameters of sound waves are amplitude, frequency, phase, length, period, duration, spectrum and others.

Sound propagating in a medium is a wave (Fig. 1.2.1) with the phases of condensation (increase of atmospheric pressure) and rarefaction (decrease of atmospheric pressure) of its particles. The distance between the middle and extreme position of the oscillating body is called the amplitude of the oscillations. The amplitude of the periodic pressure fluctuations of a propagating wave is called sound pressure. The wavelength is the distance between two areas of compression or rarefaction of it, and the frequency is the number of oscillations (compressions or rarefactions) per second. The unit of measurement for the wavelength is 1 m, and the frequency is hertz (Hz), that is, one oscillation per second. The time during which a sound wave makes a complete oscillation is called the oscillation period. The propagation velocity of acoustic waves in air is 343 m / s, water - 1480 m / s and solids - 2000 m / s at a temperature of 200 C.

Fig. 1.2.1.

The absolute unit of measurement of acoustic quantity by sound pressure is Pascal (Pa) .1Pa = 1H.m-2. The absolute threshold of human hearing at a frequency of 1000 Hz is 2.10-5 Pa, which is taken as standard sound pressure (p0).

A relative unit of measure characterizes how much the value of a given acoustic quantity exceeds its standard value. Bel and decibels (dB) are taken as relative units.

Sound pressure, expressed in decibels relative to 2.10-5 Pa, is called the sound pressure level (SPL) or SPL (Sound Pressure Level), which is calculated using the logarithm according to the formula:

SPL = k. Lg? /? 0

At k = 2, the unit of ultrasound is Bel, and at k = 20 it is decibel / dB /.

The relative energy unit of a sound wave is calculated using the intensity level (L).

L = k. Lg I / I0

The threshold intensity (I0) is the energy threshold of sound audibility in Watts at a frequency of 1000 Hz, which is 10-12W.m-2. At k = 1, the unit of the intensity level is Bel, and at k = 10 it is the decibel (dB). Three values: p = 2.10-5 Pa; I = 10-12 W.m-2 and L = 0 dB characterize the same sound, that is, they essentially correspond to the thresholds of audibility in terms of sound pressure, power and sound intensity level.

Ia? En. 1.2.2. iieacaii,? oi i? e 20 aA caoeiaia aaaeaiea (p) corresponds to a 10-fold increase in the absolute threshold sound pressure (p0 = 2? 10-5 Pa), at 40 dB it increases 100 times, at 60 dB - 1000 times, at 80 dB - 10,000 times, at 100 dB - 100,000 times, etc.

Fig.
1.2.2.

In fig. 1.2.3. absolute hearing thresholds in Pascals and their corresponding SPL in decibels are indicated. To achieve them at frequencies of 1000 - 4000 Hz, a sound pressure of 2.10-5 Pa is sufficient. At 250 and 10,000 Hz an increase in pressure is required. Therefore, the curve of the absolute thresholds of hearing is convex upward.

Fig. 1.2.3.

In audiometry, measurement of relative auditory thresholds is accepted

(HL) from the zero isoline resulting from the average hearing thresholds of young healthy people. Hearing Level (HL) - hearing level. At the factory, the audiometers are specially tuned to the initial level of 0 dB (Fig. 1.2.3.) As the minimum auditory sensation at each frequency. The zero level of the audiometer does not correspond to the level of absolute hearing thresholds.

In fig. 1.2.4. the relative threshold isoline of hearing is presented in the form of a straight zero line and its ratio with absolute thresholds (dotted line). The lower dashed curve shows the maximum level of air conduction intensity on the audiometer, where the middle frequencies (1000 - 4000 Hz) have a greater sound range than low and high frequencies.

Fig. 1.2.4.

Sensation Level (SL) - individual threshold level of hearing of the patient from an audiometric zero at the appropriate frequency.

SPL, HL, and SL are European Community (EU) terminology.

Along with physical / objective / sound concepts, there are psychophysiological concepts corresponding to them: intensity - volume, frequency - pitch, spectrum - timbre and others that are associated with a person’s auditory sensations and have other units of measure (background, chalk, etc.).

Important properties of sound include phenomena of resonance, reflection, diffraction, and others. Resonance is the property of sound to cause sound vibrations of another object. Resonance matters in the mechanism of sound conduction in the outer, middle and inner ear. The natural oscillation frequency of the sound-conducting apparatus is about 1000 Hz. At this frequency, an increased sensitivity of the ear due to resonance is noted.

The ability of a sound wave to go around obstacles is called diffraction. Low sounds have better diffraction. The reflection of a sound wave from obstacles in an open atmosphere is an echo (in a forest, mountains), and indoors - a reverberation. As a result of the meeting in the room: the acting and reflected waves, their interaction occurs, which is called interference, while the sound is amplified or weakened.

The average duration of the acoustic signal that the human ear perceives is 0.001 s. The sound impression remains in the ear for 0.009-0.1 s. The latent period of the patient’s reaction depends on the frequency and intensity of the tone: for high tones, it is shorter and inversely proportional to the intensity.

The human ear is capable of perceiving sounds from 16 to 20,000 Hz. Oscillations with a frequency of less than 16 Hz belong to infrasounds, and with a frequency of more than 20,000 Hz - to ultrasounds. However, B. M. Sagalovich (1968) notes that a person can perceive sounds from 1 Hz to 225 000 Hz, so their division into audible and inaudible is somewhat arbitrary. Sounds comfortable for our ear (noise of the forest, rain, sea) are in the range of about 1000 Hz. Human hearing acuity is most pronounced at the age of 15-30 years. The range of frequencies perceived by the ear is divided into three parts: tones up to 500 Hz are called low-frequency, from 500 to 3000 Hz - mid-frequency from 3000 to 8000 Hz - high-frequency and above 8000 Hz - super-frequency. The area of ​​speech frequencies is located in the region of 500 - 4000 Hz.

The auditory system includes sound-conducting and sound-receiving sections. The sound-conducting apparatus includes the outer and middle ear, peri-and endolymph, the main membrane, the integumentary and Reiner membranes. Sound perception begins with the receptor cells of the organ of Corti and includes the auditory centers of various levels of the central nervous system.
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PHYSIOLOGY AND METHODS OF STUDY OF HEARING

  1. PHYSIOLOGY AND CLINICAL METHODS OF STUDYING VESTIBULAR APPARATUS
    The term “aanoeaoey? Iue aiia? Ao” iaicia? A? O ioieeoiaua e ampullary receptors of the ear labyrinth. Due to the special anatomical arrangement of the semicircular canals and sacs of the vestibule, as well as the presence of an auxiliary apparatus, the ampullar receptors respond to angular acceleration, and the otolith receptors respond to rectilinear ones. Intermediaries in the perception by receptor cells of corresponding accelerations in
  2. CLINICAL ANATOMY AND PHYSIOLOGY OF THE UPPER RESPIRATORY AND EAR. RESEARCH METHODS OF ENT ORGANS
    Otorhinolaryngology is a science and practical discipline about diseases of the ear, nose, pharynx and larynx (abbreviated as ENT). Given the applied nature of the manual, it is advisable to provide the main content - a description of the diseases - with information on the clinical anatomy, physiology and research methods of these organs. Since diseases of ENT organs are often interconnected with pathology nearby
  3. Anatomy, Physiology and Pathology of the Hearing Organ
    The organ of hearing is one of those receptor (perceiving) devices by means of which communication and balancing of the animal and human organism with the external environment are carried out. These devices are called analyzers. Each analyzer is a single integrally functioning system consisting of three departments: a) peripheral, or receptor; b) average, or
  4. STUDY OF HEARING
    The main objective of hearing research is to determine the acuity of hearing, i.e., the sensitivity of the ear to sounds of different frequencies. Since the sensitivity of the ear is determined by the threshold of hearing for a given frequency, in practice, the study of hearing consists mainly in determining thresholds of perception for sounds of different
  5. Neyman L.V., Bogomilsky M.R. Anatomy, physiology and pathology of the organs of hearing and speech, 2001

  6. Researching forks with tuning forks
    A more accurate method is the study of hearing using tuning forks. Tuning forks emit pure tones, with the pitch (oscillation frequency) for each tuning fork being constant. In practice, tuning forks tuned to tone C (do) in different octaves are usually used, including tuning forks C ,, C, c, cv c2, c3, c4, c5. Hearing tests are usually performed by three (C128, C512, C2048 or C4096) or even two
  7. Hearing test
    When clarifying the patient’s complaints, attention is drawn to hearing loss in one or both ears (constant, progressive, or with periodic improvement, worsening), degree of hearing loss (hears conversation at a short distance, communication with others is difficult at work, at home or at home, is used constantly, periodically by the hearing aid, how it affects hearing acuity, hearing change in noisy
  8. Speech Research
    The simplest and most affordable method is the study of hearing by speech. The advantages of this method are the absence of the need for special instruments and equipment, as well as its conformity to the main role of the auditory function in humans - to serve as a means of verbal communication. In the study of hearing, speech uses whispering and loud speech. Of course, both of these concepts do not include the exact
  9. Hearing examination with an audiometer
    A more advanced method is the study of hearing using a modern apparatus - an audiometer (Fig. 20). {foto22} Fig. 20. Researching hearing with an audiometer An audiometer is a generator of variable electrical voltages, which with the help of a telephone are converted into sound vibrations. For the study of auditory sensitivity in air and bone
  10. Speech Research
    The distance at which the subject perceives whispering and colloquial speech serves as an indicator of visual acuity. Normally, in a whispering speech, a person hears low sounds at a distance of at least 6 m, and high ones - 20 m. The room where the study is carried out should be quiet. In a hospital, a hearing test can be performed in the patient’s room. Every doctor produces a constant whisper intensity
  11. Study of hearing in children
    The study of hearing in children should be preceded by a collection of brief anamnestic information: the course of the child’s early physical development, speech development, the time and causes of hearing loss, the nature of speech loss (simultaneously with deafness or after some time, immediately or gradually), the conditions for raising the child. In various periods of a child’s life, the occurrence of hearing loss and deafness is associated
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  13. THE METHOD OF “Slices” AND THE METHOD OF STEP-BY-STEP FORMING IN THE STUDY OF CHILD'S THINKING
    A comparison of our ideas with the ideas of J. Piaget is of great importance to us, for we also proceed from action as the central problem of mental life and psychology. We recognize that from a general biological point of view, the psyche is an auxiliary apparatus of behavior; Moreover, we believe that mental processes are nothing more than sublimated objective actions, and images -
  14. Research methods
    As the organizational methods, we used the comparative method (comparing the properties of the samples depending on the profession, place of residence and age characteristics), longitudinal (the change in the level of development of multi-ethnic competence, ethnic tolerance and emotional intelligence was monitored before and after participating in acmeological programs). As empirical methods
  15. Research methods
    The work mainly used nomothetic research method. The empirical level included the planning and organization of a study conducted in 2005-2008. The following methods were used to solve the problems posed and test hypotheses: theoretical analysis of concepts and research in the field of personality psychology, developmental psychology, differential psychology, philosophy, sociology and
  16. Research methods
    The complex and systemic approaches implemented in this study with its multifaceted nature of the tasks required required the use of various methods for collecting empirical data, diagnostics, and the formation of the procedure for their mathematical processing. Empirical research methods: observation and self-assessment method using computer technology; psychodiagnostic methods in
  17. Research method
    The study of any new field must begin with the search and development of the method. One can express in general terms the idea that any fundamentally new approach to scientific problems inevitably leads to new research methods and methods. The object and research method are closely related to each other. Therefore, the study takes a completely different look and flow then,
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