The Tones of Tinnitus: Are Those 'Sounds' That You 'Hear'?

Although you have not yet progressed to the second sentence of this lengthy paper, there is almost a 100% guarantee that, before this text directs your attention to reality and essence of tinnitus, you are already knowledgeable about the phenomenon that is the basis for the following discussion. The legitimacy of this estimate can be attributed to the presumption that, at some point in your life, you were made conscious of your ‘head noise’ through the incidence of ringing in one or both of your ears. The presence of some ‘head noise’ is ordinary and natural, and most of us are only aware of its presence through transitory yet noteworthy ringing noises in our ears. However, the variation in the overall nature perceived sound (its duration and intensity for example) and among the innumerable ways in which it has been and continues to be managed is so immense that the phenomenon as a whole demands critical consideration on multiple levels. Is the presence of such ‘head noise’ a cause or an effect in the biological sense? Is it reasonable to argue that some forms of tinnitus are evidence that we are changing our surroundings in ways that exceed our capacity to evolve? In the philosophical sense, is there a need to differentiate or to reconcile ‘head’ noise and ‘actual’ noise? Is our current and standard definition of ‘sound’ inadequate to some extent? Presumably, a discussion of this phenomenon will highlight the causes and implications of the incidence of ‘sound without sound,’ and how it relates to common notions of perception.

What is tinnitus and what constitutes ‘head noise’? The American Tinnitus Association defines tinnitus as “the medical term for the perception of sound in one or both ears or in the head when no external sound is present” (1). The perceived sound can be occasional, periodic, continuous, or recurring, and its volume can range from barely noticeable to incredibly disturbing (1). It is essential to note, however, that the ‘sound’ of tinnitus, unlike that associated with some forms of schizophrenia, does not complement everyday noises such as that of voices, music, or of chirping birds. The word ‘tinnitus’ is derived from the Latin word meaning ‘to tinkle or to ring like a bell,’ which corresponds precisely to what tinnitus patients perceive as “ringing, buzzing, roaring, whistling, or hissing” noises of varying frequency and pitch (1,2). Consequently, the tinnitus ‘noise’ is one that interferes destructively with ‘true’ external sounds and that can be immediately recognized and distinguished from these sounds at the moment that it is perceived and throughout its duration. Considerations of scientific observations will likely further and enhance an understanding of the character and of the multiple forms of this condition.

What is the scientific basis of tinnitus? The most concrete explanation of tinnitus can be localized to the cellular level. Auditory cells in the inner ear are coated with microscopic and fragile hairs that move upon interaction with sound waves (2). Movement of these small hairs generates an electrical signal that travels along the auditory nerve and to the brain, where it is interpreted and perceived as a sound (2). If such hairs are damaged (usually through overly loud noise), they move in less consistent and functional ways, thus causing undesirable leakage of electrical messages, which the brain receives and interprets as ‘noise’ (2). The identification of such auditory and neural mechanisms as a major cause of ‘head noise’ has enabled scientists and clinicians to further classify tinnitus into more rigorous forms.

Tinnitus is currently classified as one of two major forms: objective or subjective. Objective tinnitus often presents itself in the form of pulsatile tinnitus. In this form of tinnitus, the ‘sounds’ are rhythmic, and often in sync with one’s pulse (1). Such a form of tinnitus can be detected by clinicians through use of stethoscopes or sensitive microphones, and is primarily associated with underlying cardiovascular disease or health problems. The role of tinnitus as a side-effect in this case accounts for its increased responsiveness to treatments (1). The other major category of tinnitus, subjective tinnitus, is much more inexplicit. As a result, the associated treatments and their effectiveness are much more variable and inconsistent from person to person. Consequently, unlike the objective form, subjective tinnitus cannot be detected or perceived directly by a clinician (3). It is possible, though, that the intensity of both forms of tinnitus can be indirectly quantified, based solely on the brain’s ability to facilitate and to implement selectivity in the process of hearing (3).

The extent of tinnitus can be measured by having the patient listen to external sounds at a variety of decibel levels; the precise decibel level at which the patient claims he or she cannot perceive the ringing noises serves as a quantitative measurement of the intensity of their tinnitus (3). However, even this method is not entirely practical or useful, as the brain can influence and interfere with the results of such tests. For example, if the brain selects solely for the external noise that the patient is exposed to during the examination, the intensity of his or her tinnitus may be underestimated with respect to that which he or she claims to hear on a daily basis (3). Analogously, if the brain selects for the noise of the tinnitus upon exposure to the sample noise, the tinnitus ‘noise’ has a tendency to override the external noise, and thus its intensity can be greatly overestimated (3). Outside of such quantitative attempts to measure or gauge tinnitus intensity, there is no comparable uniformity or consistency associated with tinnitus, especially in the process of identifying effective treatments for patients.

It is estimated that more than 50 million Americans have some form of tinnitus, one quarter of which possess a form that is harsh enough to necessitate medical attention (1). What are the potential causes of tinnitus, and can the condition lead to further problems? Tinnitus itself is not considered to be a disease; it is generally considered to be a symptom of overexposure to loud sounds or of an underlying or preexisting medical condition (2). While tinnitus is most often linked to hearing loss as a result of overexposure to loud noise, it is also can present itself in specific circumstances; such circumstances include the buildup of wax in the ear canal, side-effects of some medications, cardiovascular problems, circulatory problems, infections, misalignment of the jaw, trauma to the head or neck, and injury to or infection of the outer, middle, and/or inner ear (1, 2, 4). In addition, the continuous ringing or squealing noises of more severe forms of tinnitus can interfere with sleep patterns, the ability to concentrate, maintenance of personal relationships, and approach to everyday activities. It can also affect psychological and neural systems, and may initiate or escalate depression and related maladies (1). While tinnitus itself is not a fatal illness, it appears to play an interesting yet irksome dual role as both a cause and an effect, and does not necessarily discriminate between the young and the elderly; some children are born with some degree of tinnitus, but they do not notice it because they are habituated to it and are much less likely to identify the existence of a bothersome ‘sound’ that they have ‘heard’ it all of their life (1). While those born with tinnitus can perhaps unconsciously select for ‘true’ external noises, the coping mechanisms for the remainder of tinnitus patients are more complicated and problematic.

Recognition and adequate management of tinnitus is established almost entirely at the personal and individual level, as the intensity, the severity, and the ability to cope with or tolerate the ‘sounds’ varies extensively from one person to the next (1). Some patients find that their tinnitus is ameliorated through use of certain medications, while others find that external noise can help them cope. Depending on their tolerance and the severity of tinnitus, patients may use devices that resemble hearing-aids to emit true sounds to mask the ‘sounds’ that they hear, while others make use of out-of-ear sound generators (radios, television, iPods, etc), psychotherapy, or counseling to help them cope. Some suggested steps toward prevention include use of ear protection upon exposure to loud everyday noises (including hair dryers, lawn mowers, music, and various other household appliances and machinery), avoidance of substances that tend to exacerbate the condition (including caffeine, nicotine, and alcohol), and management of stress and overall state of health (1). Currently, it is not known whether there is a genetic component associated with tinnitus, but researchers have identified genes for various other forms of hearing loss with which tinnitus is often an associated symptom. Most of current research on tinnitus is focused on its causes and especially methods of treatment, as increased consistency and reliability in treatments and responsiveness to them is highly desired (1).

It is essential to note that, while potency and efficiency of response to numerous forms of treatments is highly variable, the main goal of all of these mechanisms is the same; each sufferer must “retrain the brain to no longer notice the tinnitus signal” (1). The microscopic hairs on the auditory cells cannot be regenerated or repaired. In fact, especially in the case of subjective tinnitus, recovery or progress is not at all associated with detectable or visible modifications of auditory cells; rather, it is most directly correlated to one’s individual adjustment to such symptoms (2). But is our desire to ‘retrain’ the brain a logical or realistic aspiration?

It appears that recovery from tinnitus is expected if the brain could learn to ignore the ‘real’ messages that it receives from leaky membranes, and to convince itself that such messages are erroneous. But how could we possibly expect such a conversion to occur, and so readily at that? Perhaps we could compare this phenomenon to an everyday analogy; if I am in New York City and a trusty friend calls from Hawaii to tell me that it is raining in Honolulu, what would cause me to question the truth of this statement? It would not be in my friend’s best interest to lie to me, so and we have a working relationship because there is a sense of trust, so I have every right to believe her without actually double-checking all the time. Would it be worth my time and energy to fly all the way to Honolulu to confirm that it is, in fact, raining there? Most likely not, as this would be incredibly inefficient! It seems plausible then, that the unwillingness of the brain to ‘question’ the reality of its incoming auditory messages may have evolutionary underpinnings.

The brain works in our favor by striving for efficiency, and this includes communication and management of the ‘reality’ that it receives and perceives. The brain and the remainder of the nervous system in the average human have evolved to yield increased sophistication in the receiving and transmitting or signals, which has, over the course of time, engendered an analogous sense of ‘trust’ in the receiving and transmitting of signals. However, data collected on the incidence of tinnitus demonstrates that the condition is very prevalent in the modern developed world where there is increased exposure to machinery and unnaturally loud noise (3). Can we reasonably expect that the special ‘trust’ mechanism between the brain and the auditory component of the nervous system will readily dismantle itself to adapt to changes as recent as several hundred years ago? It appears not, as tinnitus is regarded, in this context, as evidence of the struggle for the brain and the auditory system to alter their relationship. Although it may seem counterintuitive, would it be wrong to say that there may actually be a positive side of tinnitus, as it potentially represents a warning that we are changing our environment faster than we are able to physically and mentally adapt?

As a result of the ‘disagreement’ between the sufferer and the brain in this matter, it often takes countless attempts to find a means reconcile the two, and such a mechanism is not always found. Consequently, treatments for tinnitus are not consistently covered by health and medical insurance, as they are often deemed ‘experimental’ (1). Thus, there seems to be a sort of closed loop of social neglect; society as a whole inflicts this problem on all of its members, but no one is willing to account for or to support the consequences of the dilemma. In the context of this economic arrangement, is an epidemic of tinnitus in industrialized countries the quicker solution to the problem? If such an epidemic leads to increased awareness on a large scale, would we not respond by devising alternative methods in industrial practices, or advocate standards for ear protection? These acts would hypothetically contribute to the maintenance of the ‘trusty’ relationship between the brain and the auditory system. Is it not more efficient to work to preserve this mechanism during our lifetimes, rather than to wait passively for the long-established mechanism to alter itself, potentially through evolution? Might tinnitus be a call for activism of some sort? The somewhat ambiguous nature of tinnitus makes it the foundation and the basis of many questions that either whose answers are either disputed or addressed only in terms of personal opinion. Such is the case in the realm of perception.

If a tree falls in a forest and no one is around to hear it, does it make a sound? The Merriam-Webster dictionary defines ‘sound’ as “mechanical radiant energy that is transmitted by longitudinal pressure waves in a material medium and is the objective cause of hearing” (5). This dictionary definition seems to acknowledge that ‘sound’ is itself a physical entity that exists outside of perception. However, at the same time, this definition suggests that our ability to distinguish and identify the physical nature of this entity in the first place was achieved exclusively through our ability to perceive it. The tinnitus phenomenon further complicates this issue of defining ‘sound,’ especially in its subjective form; especially because it is not associated with underlying medical problems, the presence of such ‘radiant energy’ does not exist when the ringing is perceived. Perhaps, then, the leaky membranes are to blame for confusion of defining sound; the output message that travels to the brain as a message lacks an identifiable ‘input.’ The ‘input’ or its source can likely be traced to the leaky membranes, or it may not exist at all.

Although the nature of this ‘input’ is rather vague, it must not be overlooked because it plays a critical role in the reafferant loop (a causal effect that is cyclic in nature, inputs and outputs are both the result and cause of each other) that characterizes nervous system functions. But if perception cannot be localized any more precisely beyond leaky membranes, and if we cannot ‘will’ our brain to distinguish what we think is ‘sound’ from what the brain believes to be ‘sound,’ how can we be sure of what we are perceiving at all? Is there a difference or disconnect between the ‘we’ and the ‘brain’? Does the brain do all of the technical work, while we oversee and criticize its activity?

In discussions that have occurred in my current Neurobiology and Behavior class, we have considered a potential link between the ‘we’ and a hypothetical region of the brain known as the I-function; we have contemplated its existence, its role in the nervous system, and even its lack of a true or valuable role. But why did we attempt to distinguish ourselves as located in the I-function, a part of our nervous system? Why would we voluntarily consider ourselves as a distinct component of a larger biological powerhouse? Are we insecure? Are we selfish? Are we ignorant? Why have we assumed that we have experiences, and that they actively cause our neurons to rearrange or readjust their synapses? Why can we not step back and consider ourselves (the ‘we’) as the component that overseen and directed? Why is it not equally as valid to say that what we perceive is nothing more than ‘virtual’ reality? Can it not be possible that our neurons are actively rearranging themselves and reforming synapses to provide us with experiences? Why do we tend to think that we define and authorize the arrangement of our neurons? Can they not define and authorize everything about us? If the ‘we’ distinguishes tinnitus as a ‘fake’ sound, but is greatly disturbed by it, and if the brain distinguishes tinnitus as a ‘real’ sound, but is not at all disturbed by it, is it possible that tinnitus is both real and unreal?

Overall, the concrete and abstract nature of this condition makes tinnitus an interesting and thought-provoking topic. While tinnitus is most notably an individual experience, it certainly has implications for us all. So, the next time that you experience ringing in one or both of your ears, recognize that you are simultaneously correct and incorrect in identifying your ‘head noise,’ that is, the ‘sound’ that you ‘hear.’

Sources

1. http://www.ata.org/abouttinnitus/patient_faq.php “About Tinnitus: Frequently Asked Questions” American Tinnitus Association (accessed 17 Mar 2008).
2. http://www.mayoclinic.com/health/tinnitus/DS00365/DSECTION=2 “Tinnitus” MayoClinic.com (accessed 21 Mar 2008).
3. http://en.wikipedia.org/wiki/Tinnitus “Tinnitus” Wikipedia.org (accessed 1 Apr 2008)
4. http://www.medicinenet.com/tinnitus/article.htm “Tinnitus: Ringing and Other Ear Noise” MedicineNet.com (accessed 21 Mar 2008).
5. http://www.merriam-webster.com/dictionary “Sound” Merriam-Webster.com (accessed 3 Apr 2008).