What is the meaning of MPO in hearing aid fitting and debugging?

Hearing aid fitting and debuggingMPOWhat do you mean?

Under the premise of selecting the shape and power of the hearing aid, an important debugging step for the hearing-impaired person to listen comfortably is the control of the maximum sound output of the hearing aid, ieMPOAdjustment. However, it is often easy to ignore in daily fittings.MPOAdjustment. Then,MPOWhat is the role of regulation? When do you want to adjust? How to adjust?

MPOversusUCLRelationship

MPOIt refers to the maximum sound output limit of the hearing aid and is the control of the maximum sound output capability of the hearing aid.

UCLThe uncomfortable threshold is the intensity at which the sound causes a significant discomfort in hearing.

We all have experience. When we hear high-intensity sounds such as firecrackers and airplanes, we often frown and habitually block our ears with both hands, because the sound size exceeds our discomfort threshold.

Therefore, it is not difficult to understand that special attention should be paid to the adjustment of the hearing aid to the hearing aid wearer.MPOTo control the maximum output of the hearing aid (MPO), ensuring that the wearer’s discomfort threshold is not exceeded (UCL).

How to test the discomfort threshold?

The discomfort threshold test is one of the pure tone hearing test items. The test steps are as follows:

The first step: testing500Hz,1000Hz,2000Hz,4000HzThe air conduction threshold of the frequency;

Step 2: Inform the subject to test the content and guide the subject to “the volume will gradually increase. If the sound is too uncomfortable, press the button or raise your hand”;

The third step: from1000HzAir conduction threshold10dBOr20dBStart with each time5dBThe increment gradually increases to the intensity of the sound until the first reaction of the subject feels uncomfortable, recording the intensity of the sound at that time, that is1000HzThe discomfort threshold.

Test the discomfort thresholds of other frequencies in the same way.

MPOWhat is the significance of the adjustment?

1. Improve speech intelligibility

Through the setting of the maximum sound output of the hearing aid, the hearing impaired person can comfortably perceive the ambient sound and the speech sound, and avoid the reduction of the loudness of the hearing aid and the decrease of the speech intelligibility.

2. Avoid acoustic damage

The maximum sound output setting for different hearing loss enables the sound signal output by the hearing aid to be within the comfortable and audible range of the hearing impaired person, avoiding the excessively large sound output setting, causing discomfort to the hearing impaired person and even damaging the residual hearing.

Especially important for children’s hearing aid fitting!

Since children are unable to subjectively describe or provide accurate feedback on over-amplified sounds, special attention should be paid to observing children’s subtle reactions in time and appropriate adjustments.MPO .

When do you need to adjust?MPO?

For the fitter,MPOThe adjustment is made at the beginning of the new hearing aid debugging, that is, after the first fitting is obtained, the target curve is adjusted according to the discomfort threshold to ensure comfortable listening.

In addition, in the subsequent return visit debugging, when encountering some problems, it also needs toMPOMake some adjustments.

Hearing Health Studio based on years of experience in fitting and researching the fitting software of major manufacturers, listed the following needs to be adjustedMPOThe situation for your reference.

Most of them are loweredMPOValue, but in the case of loud distortion, you also need to considerMPOSet the distortion caused by too low.

How to adjustMPO?

Different hearing aid manufacturers softwareMPOThe display interfaces are different, some are pure curves, some are curves plus numbers, and some are pure numbers.

however,MPOThe method of adjustment is inseparable from its sect, summed up in one sentence, the hearing aidMPOThe value is set to be no larger than the hearing impairedUCLValue.

1. If it is a pure curve or a curve plus a digital interface display, willMPOThe curve is adjusted to not exceedUCLThe curve can be.

2. If it is a purely digital interface display, that is onlyMPONumerical sumUCLValues ​​require special consideration of a problem:

Unit conversion!

we know,MPOControls the maximum sound output of the hearing aid, the displayed value on the software, and the unit is the sound pressure level (dB SPL).

AndUCLIt is the uncomfortable sound intensity measured by pure tone, and its unit is the hearing level (dB HL).

It can be seen that the units of the two are inconsistent, we are graspingMPOversusUCLFor large hours, you need to understand the zero-level sound pressure level at different frequencies (as shown in the table below).

According to the “sound pressure level value=Hearing zero-level sound pressure level+The hearing level value is used to convert the sound pressure level and the hearing level.

OnMPOWhen adjusting, willUCLThe value plus the hearing zero-level sound pressure level, and thenMPONumerical comparisons andMPOThe corresponding adjustments.