Reflex stapédien
The reflex stapédien (of Latin stapia: clamp) consists of the contraction of the muscle of the clamp of the average Oreille, aiming at attenuating the level of intensity of the sounds transmitted to the internal ear. It has three principal functions:
- a function of increase in the dynamic field of hearing, allowing a good auditive discrimination for sounds of strong intensity (up to approximately 120-130 dB, that is to say the threshold of pain). Indeed, when the reflex stapédien starts, any increase in the perceived sound is attenuated, and thus an increase of 10 dB will involve only one transmission raised of 3dB towards the internal ear. It is the principal role of the reflex stapédien: the protection of the internal ear . However, like all the muscles, the stapédius tiredness .
To 109 dB, it holds 1 mn 52 S.
To 100 dB, it resists 15 mn… on average.
Moreover like all the reflexes, the neurosensory system which implements it has a response time. At the time of an impulse noise (explosion, slapping of door) the ear is not protected. Thus, it is good to stop the ears when it is seen that there will be a great noise.
-
a function of reduction in the Effect of mask . For the sounds of strong intensities, the serious sounds tend to mask the sounds acute S. the reflex stapédien is very effective in the attenuation of the sounds whose frequency is lower than 2000 Hz, therefore the sounds medium with low register. However the comprehension of the human voice is done primarily by the correct perception of these zones of frequencies around 2000 Hz. When the reflex stapédien appears, the discrimination of the acute sounds (perception of the consonants in particular, allowing best the comprehension of the words) is better.
-
a function of auditive adaptation , the purpose of which is to make it possible the auditive system to decrease its answer.
| Random links: | Cité de l' car | Duck spatula | Andechs | Banner of Ejin Horo | Championship of Ireland of football 1943 | Magnoliopsida |