Hi Telis! This is the stuff Im talking about, and what I find so darn interesting! Ive had it many times as well, except that my tinnitus doesnt change afterwards, and if it does, its more to the better.
I believe that this is not related to the inner ear or auditory nerve pathways but rather the middle ear. It reminds me an aweful lot about the acoustic reflex. I suspect that this intermittent tinnitus is the result of muscle activity directly or indirectly related to the middle ear. Based upon my own experience, I believe the acoustic reflex can produce two types of tinnitus, a solid tone and a hiss and a temporarily hearing loss (I believe some refer this to a temporarily threshold shift) as a result of stiffening of the ossicular chain. Either because of the malleus being pulled towards the middle ear (by tensor tympani), or the stapes being pulled away from the oval window (by stapedius) or both.
Stapedius stiffens the ossicular chain by pulling the stapes of the middle ear away from the oval window of the cochlea.
Tensor tympani muscle stiffens the ossicular chain by loading the eardrum when it pulls the malleus in toward the middle ear.
I have read that even vocalization-induced stapedius reflex results in an approximate 20 dB reduction in transduction to the inner ear.
It could be that the root cause of what we experience is related to the following:
1. Tensor tympani is not able to keep the correct tension to the tympanic membrane.
2. Ossicle chain disruption
3. Central and/or the peripheral nervous system (I doubt this is the case with me though).
I really dont think this is related to the eustachian tube, as I cant see the logic and relation behind it (but who knows). Altough I believe that eustachian tube dysfunction might make one more susceptible to a perilymph fistula because of barotrauma or anything that would increase the barometric pressure inside the middle ear.
I think number one (1) can have multiple causes and result in multiple types of dysfunction, and those below could be a few of them:
a) Muscles that are attached in close proximity to the ear (neck muscles, jaw muscles, suprahyoid muscles etc) has the ability to create additional tension on the tympanic membrane, and in time stretch it. A danish ENT found that tension in the neck and jaw area directly affects how the tympanic membrane reflects light and could by that tell if neck and jaw muscles were tensed in his patients.
b) Irritation or damage of the nerves that innervates any of the muscles in the ear, especially tensor tympani in this case.
c) Related to elasticity of the tympanic membrane, or blood flow through the tympanic membrane. I think for example eczema could be one cause out of many.
d) Loud noise exposure, phonophobia, hyperacusis (as it would result in heavy load on the tympanic membrane caused by tensor tympani) or that the tensor tympani has reached some state of fatigue (not sure if that is possible, as it seem like the muscle is able to contract fast and is fatigue-resistant, but I wouldnt be surprised if this muscle could reach a state of fatigue as well).
And for number two (2):
a) A network of muscles are needed to keep the correct alignment of the middle ear ossicles. If they fail, stapedius and/or tensor tympani will try to adjust the ossicles and by that result in a temporarily hearing loss and an intermittent tinnitus by stiffening the ossicular chain by pulling the stapes away from the oval window. (I even read that stapedius is involved in the healing process of a perilymph fistula?). I also read that the SCM muscle alone was able to misalign the middle ear ossicles, affecting how they tap eachother in the process of transmission of vibrational energy to cochlea.
b) Ossicular chain disruption because of inflammatory disease, ear infection etc..
Other than that, I guess you have the obvious stuff that should be ruled out first, like perforated eardrum, sinus problems etc..
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For me, its hard to believe that its related to the inner ear, as I can feel movements in my middle ear and occasional pain that could remind of something similar to tendonitis right behind my eardrum. And when I experience intermittent tinnitus, it feels like some muscles are stretching something in and around my ear. (but that is the case with me though, and you might have something different).
Im no doctor, and I cant say anything for sure, and the stuff above is only based on information I have read and my own gut feeling and I share it in hope that you will find it somehow useful