What is the ear plugging effect of hearing aids?
It is well known that when the external auditory canal is closed (usually in the case of wearing a custom hearing aid or a lug ear mold), some hearing aid users are prone to occlusion effects, causing the hearing aid to wear discomfort.
When the low frequency hearing is less than 40 dB HL, wearing the hearing aid is prone to cause the ear plugging effect.
After wearing the hearing aid, even if the switch has not been turned on, some people will feel that they have echoed their voices, and they are as if they are talking in a wooden barrel. This is because the ear mold (or custom hearing aid housing) closes the external auditory canal, and the sound of the self-talk is transmitted through the middle ear and the skull, causing the vibration of the external ear canal cartilage. Under normal circumstances (without hearing aids) the external auditory canal is open and this vibrational energy is released without being noticed. When the external auditory canal is closed by the ear mold, this part of the energy is left in the external auditory canal, thereby causing the above phenomenon. This phenomenon is called "plugging effect" in medicine.
Four ways to solve the ear plugging effect of hearing aids
The individual effects of the ear plugging effect are very different. If there is a blocking effect, it should be solved according to the following method.
a.First check the ear canal portion of the hearing aid or ear mold. The ear canal portion of a poorly prepared hearing aid (ear mold) may be relatively imaginary, which may cause the hearing aid (ear mold) to be biased toward the side of the ear canal wall. This condition may also be caused by the effect of the ear cavity. The ear cavity effect means that there is an angle between the ear canal portion of the hearing aid and the bottom of the ear cavity, and the ear canal is sealed. At this time, it is necessary to polish the surface of the hearing aid to reduce the degree of sealing with the external auditory canal and reduce the effect of blocking the ear.
b.Increase the diameter of the vent. The inner diameter of the vent hole is increased and the length is shortened, which causes the low frequency cutoff frequency to shift upward and increase the low frequency attenuation. Reduce the ear plugging effect. With open hearing aids, it has better wearing comfort than traditional hearing aids.
c.Extend the ear canal portion of the hearing aid. According to the acoustic principle, the smaller the closed cavity formed by the hearing aid and the external auditory canal, the smaller the ear blocking effect.
d.A small number of patients are extremely sensitive to the ear plugging effect. For this type of patient, you can only persuade it to adapt slowly. In addition, the current open ear selection concept makes the ear free to breathe.
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