Sound of tinnitus of music composer Bedrich Smetana

Famous czech composer Bedrich Smetana, who lived in 19th century (this year was 190th birth anniversary and 130th death anniversary), suffered with deafness and also with tinnitus (it happened in year 1874 and it continued until his death, thus its 140th anniversary - strange indeed!). In one of his works, Quartet No. 1 in E Minor (subtitled "From my life" - with autobiographical character), he placed sound which corresponded with his tinnitus - a constant high-pitched tone played by violin. You can hear it now:

Anatomy of human ear I. – An overview

I do not want to bother reader with wide explanation and therefore I provide only quick overview. Human ear, like ear of all mammals, consists of three main parts: outer ear, middle ear and inner ear.

Anatomy of human ear

Outer ear

Outer ear serves to gather sound waves and to lead them into external auditory canal, which is capped with drum called tympanic membrane. This membrane transfers vibrations further into middle ear.

Middle ear

Tympanic membrane carries sound forward to three bones named: hammer (malleus), anvil (incus), and stirrup (stapes). They amplify the sound (nearly thirty times) and bring it to the snail-shaped organ called cochlea, which is already element of inner ear.

Inner ear

Inner ear is neurosensory part of ear, which is literally “electronics” of ear as a whole – and it is highly sensitive to damage. Cochlea or cochlear apparatus or Organ of Corti is placed directly in cranial bone and it contains around 16000 neurosensory hearing cells called hair cells. These are of two types: inner hair cells (IHC) and outer hair cells (OHC). Function of IHC is to change sound waves to electric signal, which goes through auditory nerve or Cochlear nerve into brain. OHC serve as additional amplifier of those signal.
Damaged hair cells (most often by acoustic trauma) can't accomplish their purpose and outcome of such state is hearing loss. IHC are in general more resistant to damage than OHC, which are dying sooner and thus amplifying of sound is not sufficient – it results in lower hearing sensitivity.

Here is very illustrative video on this issue:



On the following image we can see the difference between intact and damaged hair cells:

source: pnas.org

Hyperbaric oxygen therapy as tinnitus treatment

If you are so unlucky and ringing in ears suddenly appears, promptly locate the closest medical facility with a hyperbaric chamber. Hyperbaric oxygen therapy (HBO) can significantly reduce symptoms of acoustic trauma, if applied in short time. Best immediately of course, because each day of delay reduces its effect.

HBO has a very large potential and really cures a lot of human ills, from traumatic brain injury after an accident to the complications caused by diabetes.

Hyperbaric chamber (source: wikimedia.org)

A hyperbaric chamber is substantially pressurized tank, where you breath 100% oxygen at higher pressure than atmospheric. Chamber pressure usually resides around 2.5 atmospheres. Such pressure dissolves up to 460% more oxygen in the blood than the atmospheric pressure. It is not only bound to the hemoglobin of blood cells, but is directly dissolved in the blood plasma and penetrates into the cells by diffusion (remember that auditory cells breathe only by diffusion). Theoretically, if we increase the pressure in the chamber by about 1 more atmosphere, the body would allegedly not need red blood cells for its survival.

With timely application of HBO damaged auditory cells can survive. I have myself attended 36 sessions in a hyperbaric chamber. Unfortunately, I learned about it almost a month after my accident, so its help at that time was only limited. Nevertheless, I believe that without treatment, even though late, I would now have my tinnitus much worse.

See one interesting paper on the basis of experience implies that HBO may be effectivelly used up to 3 months after the acoustic trauma or ototoxic damage:

http://www.ncbi.nlm.nih.gov/pubmed/9547879

Interesting curiosity: During one session in the hyperbaric chamber I have purposely held my breath, so that I can verify purity of oxygen. I endured not to breathe for the whole 5 minutes! While in the atmospheric pressure I can hold breath for less than 40 seconds.