Tinnitus: A Journey of Discovery
Grant D. Searchfield, Ph.D.
Tinnitus (ear noise) is a common complaint poorly understood by most people and often misrepresented as a minor nuisance. It’s true that for many people tinnitus is a very occasional slight irritation, but some people do suffer and are tormented by the sounds within. While there’s still no cure for tinnitus, now more than ever there’s a wide range of options for its management and treatment. Since the Third Edition of this book, development of miniaturized computer technology and new understanding of tinnitus has resulted in some tinnitus treatment innovations. In this chapter, I’m going to take you on a journey of discovery, from tinnitus onset through to recovery. The information presented here should help you, your family and friends understand tinnitus and options for treatment. On this journey, I’ll introduce some of the most recent treatment ideas and things you can do yourself to reduce tinnitus annoyance. In reading this I hope you’ll discover what tinnitus is, how it is managed and signs that you’re on the right track for tinnitus recovery. Along the way I’ll offer some useful tips to help you on your journey.
Tinnitus is hearing a sound that isn’t present in our environment. The phrase “ringing in the ears” is sometimes used, but a ringing sound is just one example of different perceptions that can be classified as tinnitus (buzzing, hissing, cricket sounds are heard alongside many other sounds). A lot of people experience some degree of tinnitus. The American Tinnitus Association (www.ata.org) estimates that as many as 12 million Americans are sufficiently affected by tinnitus that they should seek professional help. Although some people see tinnitus as a by-product of our noisy, stressful modern life, tinnitus has accompanied ear injuries throughout human history. Theories have abounded as to its origins. It was once even attributed to supernatural or religious causes.1 With development of science and modern medicine, tinnitus became linked to hearing loss. It’s now considered not to arise just as a sound signal at the ear, but instead is considered to be the end consequence of a cascade of events, usually commencing with acoustic injury. Tinnitus is the result of a complex interplay of different regions of the brain.
How Tinnitus Develops
Most people with tinnitus have a hearing loss. This sometimes can be quite minor, and the tinnitus sound is often associated with areas responsible for hearing of similar normal sounds. While hearing damage is a common element in most cases of tinnitus, it’s only part of a complex puzzle. Increasing evidence from studies of how the brain works suggests that processing within the auditory pathways enhances changes in output from the cochlea—the complex portion of the inner ear necessary for hearing. Activity of the hearing system is altered enough to create an image of sound that’s actually not there. This is why tinnitus is sometimes called a phantom sound. Scientists believe that some tinnitus is created by a disruption in the balance of inhibitory (stops or slows) activity and excitatory (increases) activity. These inhibitory and excitatory processes emphasize irregularities in auditory activity. The persistent altered input to the central auditory system is believed to eventually result in functional changes in the auditory cortex (hearing center of the brain), perhaps so that it becomes synchronized to the new activity. Simply stated, it appears that the central auditory pathways overcompensate for ear injuries (even very small ones) creating tinnitus.2 In other words, tinnitus is a reflection of a change in the auditory system. After hearing damage, the brain attempts to adapt to the new pattern of acoustic input. Over time, the hearing pathways change their function. This can be rapid or slow. The capability of the brain to change over time is known as plasticity.
The impact of tinnitus on how well we feel is not fully explained by the amount of hearing injury. There’s usually a weak relationship between the extent of hearing loss and tinnitus impact. More hearing loss does not mean worse tinnitus. The brain’s system responsible for emotion, called the limbic system, is strongly implicated in tinnitus perception and understanding this has become an important part of many treatments.3 It’s thought that much of the severity of tinnitus relates to your psychological response to the abnormal perception. Things that we often don’t consider part of the hearing process, such as stress, anxiety and depression, can all lead to more severe tinnitus. Traumatic life events (e.g., death of spouse, loss of employment, ill health) frequently coincide with reported awareness of tinnitus.