What do you know about real ear analysis?

Refinement to the field of hearing aids refers to the acoustic measurement around the interventional gain at the position near the eardrum. Through the measured data, we can understand more objectively the actual compensated sound of the hearing aid, whether it can meet the hearing requirements of the patients: whether it can be heard in a low voice, whether it can be heard clearly in a middle voice, and whether it is difficult to hear it in a loud voice. At the same time, we also need to accurately adjust the parameters of the hearing aid according to the test data to achieve the best effect.

People’s external auditory canal plays a role in resonance amplification of sound, but the acoustic characteristics of each person’s external auditory canal are different, and the acoustic characteristics of children’s and adults’ external auditory canal are very different, so if only traditional evaluation methods are used, accurate results will not be obtained. For example, children can’t cooperate with behavioral audiometry, so they can only use electrophysiological methods to evaluate hearing threshold, because of middle ear and inner ear diseases leading to hearing fluctuation, etc.
Our real ear analysis will penetrate the probe tube of the collected sound into the eardrum near the external auditory canal, record the gain of the hearing aid at the eardrum near the human ear, make the effect of the hearing aid selected by the audiologist or the matched examiner more accurate, and debug the gain value of the hearing aid that best meets the needs of the patient.

For the understanding of voice, very young children can’t express at all, while older children often can’t express clearly because they are exposed to clear voice for the first time. So, can the amplification of children’s hearing aids meet the needs of children’s speech development? Is the amplification reasonable and safe? We can measure it objectively through true ear analysis.

As shown in the figure above, the real ear analysis will accurately calculate the gain of loud target (purple dotted line), medium target (orange dotted line) and low target (blue dotted line) according to the child’s listening chart. The actual gain of the hearing aid: the actual gain of the loud (purple solid line), the actual gain of the middle (orange solid line) and the actual gain of the low (blue solid line), if they are as close to the target gain as possible, and the maximum output (green solid line) can be within the safe range (green dotted line). Such debugging data is the best debugging for children. Of course, it is important to test the audiogram accurately. Moreover, the actual gain curve should be lower than the target gain curve for the hearing impaired people who wear hearing aids for the first time or who just wear hearing aids.

80% of children’s language is formed between 1-3 years old. Many deaf mute children are mainly due to the late diagnosis and correction of deafness, so we have been emphasizing early intervention. The premise and key of deafness is to accurately detect children’s hearing, select appropriate hearing aids, and enlarge the hearing aids to meet the needs of children’s language development.

1. Real ear unaided gain (reug), also known as real ear unaided response (reur), is the response of the ear canal to the sound source when the hearing aid is not worn, and is the natural amplification characteristic of the outer ear canal, with great individual differences. Its measurement is to insert a probe tube into the ear canal near the tympanic membrane when the ear canal is completely open, detect the sound intensity of each frequency point in the ear canal from the probe tube, and subtract the sound source sound pressure level recorded by the reference microphone near the outer ear canal mouth.

2. Real ear aid gain (reag), also known as real ear aid response (real ear aid response), refers to the gain or response of the sound pressure level near the eardrum minus the sound source sound pressure level recorded by the reference microphone near the outer ear canal mouth under the working condition of the hearing aid.

3. Real ear insertion gain (reig), also known as real ear insertion response (reir), refers to the difference of sound pressure levels near the tympanic membrane when the ear canal is equipped with hearing aid or not. That is to say, the data obtained by subtracting the real hearing aid gain from the real hearing aid gain.
The difference between it and the real ear hearing aid is that the interference gain takes into account the natural change effect of the ear channel on the characteristics of the sound source, while the real ear hearing aid gain does not take into account this factor.

4. Real ear occluded gain (Reor), also known as real ear occluded response (Reor), refers to the gain or response of ear canal equipped with ear mold or hearing aid (the hearing aid does not work), which is obtained by subtracting the sound pressure level near the tympanic membrane from the sound source recorded by the reference microphone near the outer ear canal.
It reflects the effect of earplugs, ear molds and hearing aids inserted into the ear canal on the natural characteristics of the auricle and ear canal.

5. Real ear coupler difference (recd) refers to the difference between the response of the hearing aid near the tympanic membrane of the real ear and its response in the 2cc coupling cavity.
It reflects the difference of the change of the output frequency response of the hearing aid due to the head, auricle, ear canal, etc. after wearing the hearing aid in the simulation ear test of 2cc coupling cavity and the real ear test.

• 1. Environmental requirements: the environment is quiet, and the patient should keep quiet as much as possible during the test.
Clean the outer ear canal: please clean the outer ear canal before testing.
• 3. Speaker orientation: generally use an angle of 0 ° or 45 ° between the sound source and the test ear, keep the tester at the same level with the speaker, about 50cm away from the speaker.
• 4. Test signal: internal sound, narrowband noise, wideband noise, speech noise, etc.
5. Position of test probe: generally, the probe should be 5mm higher than the inner end of hearing aid or ear mold, and the position should be as deep as possible < br >
(recommended depth is 31mm for adult male, 28mm for female, 20-25mm for children and 10-15mm for infants)