Acoustic qualification of tinnitus will include measurement of several acoustic parameters like frequency in cases of monotone tinnitus or frequency range and bandwidth in cases of narrow band noise tinnitus, loudness in dB above hearing threshold at the indicated frequency, mixing-point, and minimum masking level.[51] In most cases, tinnitus pitch or frequency range is between 5 kHz and 10 kHz,[52] and loudness between 5 and 15 dB above the hearing threshold.[53]
To understand what causes tinnitus, you first need to understand what tinnitus is. Tinnitus is, very simply, unexplainable noises you hear in your head when there is no actual sound present. A person with tinnitus will often hear a whistling, humming, buzzing, whooshing, clicking or ringing in their ears, even when there is nothing in the area that is emitting that particular sound. It may be intermittent or last only a short time or never seem to stop.
Experts believe that tinnitus is associated with neural (brain and nerve) injuries that affect the auditory pathway and therefore someone’s ability to hear sounds. (10) Most of the time, tinnitus is a result of a disorder that affects parts of either the outer, inner or middle ear. The good news is that the majority of cases are not linked to any serious illness, although some cases are.
Schecklmann et al (2014) suggested that tinnitus is associated with alterations in motor cortex excitability, by pooling several studies, and reported that there are differences in intracortical inhibition, intra-cortical facilitation, and cortical silent period. We doubt that this means that motor cortex excitability causes tinnitus, but rather we suspect that these findings reflect features of brain organization that may predispose certain persons to develop tinnitus over someone else.
Microvascular compression may sometimes cause tinnitus. According to Levine (2006) the quality is similar to a "typewriter", and it is fully suppressed by carbamazepine. It seems to us that response to carbamazepine is not a reliable indicator of microvascular compression as this drug stabilizes nerves and lowers serum sodium. Nevertheless, this quality of tinnitus probably justifies a trial of oxcarbamazine (a less toxic version of carbamazepine).
Patients with head or neck injury may have particularly loud and disturbing tinnitus (Folmer and Griest, 2003). Tinnitus due to neck injury is the most common type of "somatic tinnitus". Somatic tinnitus means that the tinnitus is coming from something other than the inner ear. Tinnitus from a clear cut inner ear disorder frequently changes loudness or pitch when one simply touches the area around the ear. This is thought to be due to somatic modulation of tinnitus. We have encountered patients who have excellent responses to cervical epidural steroids, and in persons who have both severe tinnitus and significant cervical nerve root compression, we think this is worth trying as treatment.
The degree of loudness or annoyance caused by tinnitus varies greatly from one individual to another. Loudness and annoyance do not always covary. An individual with loud tinnitus may not be troubled, while an individual with soft tinnitus may be debilitated. Most individuals with subjective tinnitus have hearing loss that shows up in a standard clinical audiogram. Tinnitus can sometimes worsen or sometimes improve over time.
Ototoxic drugs can also cause subjective tinnitus, as they may cause hearing loss, or increase the damage done by exposure to loud noise. Those damages can occur even at doses that are not considered ototoxic.[30] Over 260 medications have been reported to cause tinnitus as a side effect.[31] In many cases, however, no underlying cause could be identified.[2]
In the advance online edition of Nature on January 12, 2011, the researchers reported that the number of neurons tuned to the high frequency had jumped by 79% compared to control rats. The scientist then tested 2 different tones in a second group of rats but stimulated the vagus nerve only for the higher one. The neurons tuned to the higher tone increased by 70%, while those tuned to the lower one decreased in number. This showed that the tone alone wasn’t enough to initiate the change; it had to be accompanied by VNS.
If you are living with tinnitus, contact the Sound Relief Hearing Center. We are the tinnitus experts you need to experience the best possible outcome with your tinnitus treatment. To learn more about us, please browse our website or give us a call at 720-259-9962. You can also schedule an appointment online to meet with one of our tinnitus specialists. We look forward to hearing from you!
Cartoon of the middle ear showing muscles that attach to ossicles (ear bones), and ear drum. The stapedius is attached to the stapes (of course -- horseshoe object above), while the tensor tympani is attached to the ear drum. While useful, be aware that there are multiple errors in this illustration from Loyola Medical School. With permission, from: http://www.meddean.luc.edu/lumen/meded/grossanatomy/dissector/mml/images/stap.jpg
A diagnosis of tinnitus is based upon identification of characteristic symptoms, a detailed patient history, a thorough clinical evaluation and complete audiologic testing. These steps will help to differentiate rhythmic tinnitus from non-rhythmic tinnitus. It cannot be overemphasized that tinnitus is a symptom of another underlying condition and not a diagnosis in and of itself. Because of the high number of underlying causes of tinnitus, a variety of specialized tests to detect the specific cause may be necessary. Attempting to identify the underlying cause of tinnitus is the first step in evaluating a person with tinnitus.
Ringing-in-the-ears or a fullness-of-the-head sensation are the most common symptoms of tinnitus. While ringing is the most common experience, the noise can also sound like a buzzing, hissing or whizzing sound. It can range from a low pitch to a high pitch and may be soft or loud at times. For some, tinnitus seems to get louder at night, just before sleep when no other sounds are competing with it. Tinnitus can remain constant or come and go intermittently. In severe cases, the ringing in the ears is loud enough to interfere with work or daily activity, whereas those with mild tinnitus can experience soft ringing that is no more than a minor annoyance.
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