STUDY - Technical - New Dacian's Medicine
Hearing
disorders
(2)
Translation Draft
Let's continue with the lab investigations... Quantification of hearing-hearing disease is carried out with an audiometer, an electronic device that allows the presentation of specific frequencies at specific intensities at the level of each ear, either by aerial conduction or by bone conduction.
The test is performed in a soundproof room, usually applying ears that do not test a background noise, so that the answers are based on the perception of the investigated ear. In clinical practice frequencies between 200 and 8000 Hz are used, the responses being measured in decibels (dB). A dB is equal to 10 times the logarithm of the ratio of the acoustic power required to reach the threshold in a person with normal hearing.
The audiogram is the graphical representation (depending on frequency) of the intensity in dB needed to reach the threshold potential. The audiometric pattern of hearing-hearing has often diagnostic value.
Transmission hypoacusis usually has relatively equally increased thresholds for each frequency. High-mass transmission hypoacusis, as often found in middle ear exudates, have higher response thresholds at higher frequencies. Transmission hypoacusis with a large retractable component, as in the case of fixing the stair leg in incipient otosclerosis, have higher thresholds at lower frequencies.
In general, perception hearing-so-called hearing leave has increasing thresholds as frequency increases. Interesting exceptions to this rule make deafness caused by loud noises, in which hearing loss at 4000 Hz is higher at higher frequencies and Meniere's disease, especially in the early stages of the disease, where thresholds are higher at lower frequencies than at high frequencies.
Voice audiometry provides additional essential information. The spondee threshold is defined as the intensity at which speech makes sense and is obtained by representing bisilabic words through the audiometer, accentuating both syllables equally. The intensity at which the patient can correctly repeat 50% of the words is the spondee threshold and usually approximates the average response threshold to conversational frequencies (50, 1000 and 2000 Hz). After determining the spondee threshold, discrimination or the ability to recognize words shall be tested, presenting monosyllabic words at 25-40 dB above the spondee threshold.
Words are phonetically balanced (EF), in the sense that phonemes (speech sounds) appear in the list of words with the same frequency as they are encountered in ordinary conversational English. A person with normal hearing can correctly repeat 90 to 100% of the words EF. Also, people with transmission hearing loss do well in discrimination tests.
On the other hand, patients with hearing loss of perception have a reduction in discrimination, which can be attributed to a decrease in peripheral sound analysis in the inner ear or nerve VIII. In the case of a lesion in the inner ear, discrimination is moderately affected, usually within the limit of 50 - 80%, while in the case of neuronal lesions, discrimination is severely affected, often within limits of 0 - 50%.
Discrimination tests can then be performed at intensities greater than 25 to 40 dB above the spondee threshold to determine the performance-intensity function. The deterioration of the ability to discriminate at higher intensities suggests the existence of damage to the VIII nerve or central auditory tract.
Timpanometry measures the impedance of the middle ear to sound. A sound source, microphone and a sealing device shall be inserted into the hearing duct. The microphone quantitatively measures the sound that is absorbed into or reflected by the middle ear. More sounds are reflected in the transmission hearing loss than in the normal middle ear. The pressure in the auditory conduction may be increased or decreased in relation to atmospheric pressure.
Normally, the middle ear has the highest compliance with atmospheric pressure. In the case of negative pressure in the middle ear, as in the case of obstruction of Eustache's tube, the point of maximum compliance occurs at negative pressure in the auditory canal. In case of osciolare chain interruption, a maximum compliance point cannot be obtained.
Timpanometry is particularly useful for identifying and diagnosing fluid discharges from the middle ear in children. During timenanometry, an intense tone (80 dB above the audible threshold) causes contraction of the stair muscle. Changes in the composition of the middle ear can be detected when the stair muscle is contraction. The presence or absence of this acoustic reflex is important for the anatomical localization of facial nerve paralysis. The presence or absence of decreased acoustic reflex helps to differentiate sensory and neural hearing loss. In neuronal hearing leave, the reflex adapts or decreases over time.
In order to assess a patient with hearing loss, the minimum audiological investigation should include: determination of the threshold for detection of a pure tone by air and bone conduction, spondee threshold, score on discrimination tests, performance-intensity function, otoacoustic emission (EOA), timpanometry, acoustic reflexes and diminution of acoustic reflex.
These data carry out a comprehensive screening evaluation of the entire auditory analyzer and allow to determine the need for further investigations aimed at differentiating sensory (cochlear) hearing loss from neuronal (retrocochlear) hearing loss. In addition to these tests, recovery testing, index of sensitivity to small frequency increases, reduction of tone, Bekesy audiometry, evoked auditory brain potentials (PAE) help to differentiate the site of neurosensory hearing loss.
In response to sound stimuli, 5 distinct waves with electrodes placed on the scalp and connected to a computer can be recorded. Diminished or absent waves, abnormal wave latency, abnormal latency of the interval between waves are evidence of nerve viii and brain stem lesions. In addition, EAPs are useful in which patients cannot or do not want to voluntarily provide credible hearing thresholds.
They are also used to measure auditory function in newborns and young children and to monitor the integrity of the auditory nerve and brain stem in various clinical situations, including intraoperatively, and to determine brain death.
Otoacoustic emissions can be measured with sensitive microphones inserted into the external auditory conduction in infants, children and adults. Emissions can be spontaneous or evoked by sound stimulation. The presence of otoacoustic emission (EOA) indicates that external ciliated cells are intact and can be used as an important argument in differentiating sensory and neuronal hearing loss.
Otoacoustic emissions are especially strong in infants. EOA measurement can be carried out quickly and with technical equipment limited to newborns. It is not certain whether EOA or automatic PAE will become the preferred method of screening hearing disorders in newborns. One strategy is to screen all newborns with EOA and confirm hearing disorders with PAE.
High-risk factors include: family history of hearing impairment, prenatal infections, prematurity, low birth weight, neonatal anoxia, low Apgar score, neonatal jaundice and neonatal infections. Unfortunately, 50% of children with severe hearing impairment are not identified by the use of EAP in children at high risk (generally, the average age at which severe hearing disorders are identified is 2 and a half years).
The normal acquisition and development of speech and language depends on auditory function. The critical period for language acquisition is the first 2 years of life. Therefore, early identification of infant hearing disorders is of particular importance, so that hearing amplification with a special aids device and special education can be started from the first months of life.
In addition, compared to the universal screening for hearing disorders in infants, hearing should be evaluated in all children before the first formal educational experience (kindergarten or preschool). Hearing should also be evaluated in the late period of adolescence, when otosclerosis and noise-induced hearing loss begin to occur, and in the 6th decade of life, when presbciacusis occurs.
In addition to the risk factors already mentioned, known causes of hearing impairment are meningitis, cytomegalovirus infections, head trauma, infections and discharges of the middle ear, administration of ototoxic drugs (e.g. salicylates, quinine and its synthetic analogues, aminoglycoside antibiotics, furosemide-like diuretics and etacrinic acid and anticancer chemotherapy of the cis-platinum type) and exposure to noise. Whenever one of these risk factors occurs in the course of his life, an audiological assessment should be carried out.
Hey, but it's a holiday, a day off... If I want to get a good spot on green grass, I have to go NOW... And, there's my father's birthday... Happy birthday, Old Man! I'm coming to your party... Can you hear me???
Let's continue with the lab investigations... Quantification of hearing-hearing disease is carried out with an audiometer, an electronic device that allows the presentation of specific frequencies at specific intensities at the level of each ear, either by aerial conduction or by bone conduction.
The test is performed in a soundproof room, usually applying ears that do not test a background noise, so that the answers are based on the perception of the investigated ear. In clinical practice frequencies between 200 and 8000 Hz are used, the responses being measured in decibels (dB). A dB is equal to 10 times the logarithm of the ratio of the acoustic power required to reach the threshold in a person with normal hearing.
The audiogram is the graphical representation (depending on frequency) of the intensity in dB needed to reach the threshold potential. The audiometric pattern of hearing-hearing has often diagnostic value.
Transmission hypoacusis usually has relatively equally increased thresholds for each frequency. High-mass transmission hypoacusis, as often found in middle ear exudates, have higher response thresholds at higher frequencies. Transmission hypoacusis with a large retractable component, as in the case of fixing the stair leg in incipient otosclerosis, have higher thresholds at lower frequencies.
In general, perception hearing-so-called hearing leave has increasing thresholds as frequency increases. Interesting exceptions to this rule make deafness caused by loud noises, in which hearing loss at 4000 Hz is higher at higher frequencies and Meniere's disease, especially in the early stages of the disease, where thresholds are higher at lower frequencies than at high frequencies.
Voice audiometry provides additional essential information. The spondee threshold is defined as the intensity at which speech makes sense and is obtained by representing bisilabic words through the audiometer, accentuating both syllables equally. The intensity at which the patient can correctly repeat 50% of the words is the spondee threshold and usually approximates the average response threshold to conversational frequencies (50, 1000 and 2000 Hz). After determining the spondee threshold, discrimination or the ability to recognize words shall be tested, presenting monosyllabic words at 25-40 dB above the spondee threshold.
Words are phonetically balanced (EF), in the sense that phonemes (speech sounds) appear in the list of words with the same frequency as they are encountered in ordinary conversational English. A person with normal hearing can correctly repeat 90 to 100% of the words EF. Also, people with transmission hearing loss do well in discrimination tests.
On the other hand, patients with hearing loss of perception have a reduction in discrimination, which can be attributed to a decrease in peripheral sound analysis in the inner ear or nerve VIII. In the case of a lesion in the inner ear, discrimination is moderately affected, usually within the limit of 50 - 80%, while in the case of neuronal lesions, discrimination is severely affected, often within limits of 0 - 50%.
Discrimination tests can then be performed at intensities greater than 25 to 40 dB above the spondee threshold to determine the performance-intensity function. The deterioration of the ability to discriminate at higher intensities suggests the existence of damage to the VIII nerve or central auditory tract.
Timpanometry measures the impedance of the middle ear to sound. A sound source, microphone and a sealing device shall be inserted into the hearing duct. The microphone quantitatively measures the sound that is absorbed into or reflected by the middle ear. More sounds are reflected in the transmission hearing loss than in the normal middle ear. The pressure in the auditory conduction may be increased or decreased in relation to atmospheric pressure.
Normally, the middle ear has the highest compliance with atmospheric pressure. In the case of negative pressure in the middle ear, as in the case of obstruction of Eustache's tube, the point of maximum compliance occurs at negative pressure in the auditory canal. In case of osciolare chain interruption, a maximum compliance point cannot be obtained.
Timpanometry is particularly useful for identifying and diagnosing fluid discharges from the middle ear in children. During timenanometry, an intense tone (80 dB above the audible threshold) causes contraction of the stair muscle. Changes in the composition of the middle ear can be detected when the stair muscle is contraction. The presence or absence of this acoustic reflex is important for the anatomical localization of facial nerve paralysis. The presence or absence of decreased acoustic reflex helps to differentiate sensory and neural hearing loss. In neuronal hearing leave, the reflex adapts or decreases over time.
In order to assess a patient with hearing loss, the minimum audiological investigation should include: determination of the threshold for detection of a pure tone by air and bone conduction, spondee threshold, score on discrimination tests, performance-intensity function, otoacoustic emission (EOA), timpanometry, acoustic reflexes and diminution of acoustic reflex.
These data carry out a comprehensive screening evaluation of the entire auditory analyzer and allow to determine the need for further investigations aimed at differentiating sensory (cochlear) hearing loss from neuronal (retrocochlear) hearing loss. In addition to these tests, recovery testing, index of sensitivity to small frequency increases, reduction of tone, Bekesy audiometry, evoked auditory brain potentials (PAE) help to differentiate the site of neurosensory hearing loss.
In response to sound stimuli, 5 distinct waves with electrodes placed on the scalp and connected to a computer can be recorded. Diminished or absent waves, abnormal wave latency, abnormal latency of the interval between waves are evidence of nerve viii and brain stem lesions. In addition, EAPs are useful in which patients cannot or do not want to voluntarily provide credible hearing thresholds.
They are also used to measure auditory function in newborns and young children and to monitor the integrity of the auditory nerve and brain stem in various clinical situations, including intraoperatively, and to determine brain death.
Otoacoustic emissions can be measured with sensitive microphones inserted into the external auditory conduction in infants, children and adults. Emissions can be spontaneous or evoked by sound stimulation. The presence of otoacoustic emission (EOA) indicates that external ciliated cells are intact and can be used as an important argument in differentiating sensory and neuronal hearing loss.
Otoacoustic emissions are especially strong in infants. EOA measurement can be carried out quickly and with technical equipment limited to newborns. It is not certain whether EOA or automatic PAE will become the preferred method of screening hearing disorders in newborns. One strategy is to screen all newborns with EOA and confirm hearing disorders with PAE.
High-risk factors include: family history of hearing impairment, prenatal infections, prematurity, low birth weight, neonatal anoxia, low Apgar score, neonatal jaundice and neonatal infections. Unfortunately, 50% of children with severe hearing impairment are not identified by the use of EAP in children at high risk (generally, the average age at which severe hearing disorders are identified is 2 and a half years).
The normal acquisition and development of speech and language depends on auditory function. The critical period for language acquisition is the first 2 years of life. Therefore, early identification of infant hearing disorders is of particular importance, so that hearing amplification with a special aids device and special education can be started from the first months of life.
In addition, compared to the universal screening for hearing disorders in infants, hearing should be evaluated in all children before the first formal educational experience (kindergarten or preschool). Hearing should also be evaluated in the late period of adolescence, when otosclerosis and noise-induced hearing loss begin to occur, and in the 6th decade of life, when presbciacusis occurs.
In addition to the risk factors already mentioned, known causes of hearing impairment are meningitis, cytomegalovirus infections, head trauma, infections and discharges of the middle ear, administration of ototoxic drugs (e.g. salicylates, quinine and its synthetic analogues, aminoglycoside antibiotics, furosemide-like diuretics and etacrinic acid and anticancer chemotherapy of the cis-platinum type) and exposure to noise. Whenever one of these risk factors occurs in the course of his life, an audiological assessment should be carried out.
Hey, but it's a holiday, a day off... If I want to get a good spot on green grass, I have to go NOW... And, there's my father's birthday... Happy birthday, Old Man! I'm coming to your party... Can you hear me???
Have a good day, everyone!
Dorin, Merticaru