The human stapedius-muscle

The proliferation of wind turbines in the US has led me progressively further into the human auditory system’s mechanics and further, into the neuroscience of hearing. This is an absolutely fascinating realm, especially so when uncovering the gradual changes in scientific understanding of how the ear hears. Of course the “ear” is not just what we see on the outside of the head. Hearing goes all the way from the outer ear deep into the mysterious workings of our plastic brain.

This web site below surfaced today during a search about the stapedius-muscle reflex. I highly recommend it. While much of it may feel dense at first, reading this article is a lot like spelunking in a cave, uncovering brilliant gems of information about one of the most miraculous gifts we have been given as humans- our hearing. My interest, of course, is in the effects of very low frequency sound (such as that emitted by wind turbines) on human physiology.

The stapedius-muscle contraction reduces sound transmission at low sound frequencies at higher sound pressure levels. Does the stapedius-muscle reflex fire off when moderately intense infrasonic pulsations repeatedly enter the ear? It’s not clear if it does. If it doesn’t fire off, thereby leaving the inner ear open to higher pressure levels from infrasonic pulsations, could that play a role in gradual and cumulative dose-response impacts on the vestibular organs, such as vertigo, dizziness, even nausea? The stapedius-muscle reflex is one of several ways that the auditory system protects the inner ear. Are there other ways that infrasonic pulsations might bypass these protections and induce inertial movements in the vestibular organs (whose primary role is to sense their own movement)? Is it appropriate to say “no” without proof that these potentials do not exist?

Auditory system: Peripheral nonlinearity and central additivity, as revealed in the human stapedius-muscle reflex.