Nothing Is as Loud as a Sound You Are Trying Not to Hear
MARK S. SCHWARTZ
"Tinnitus" is derived from the Latin word tinnire, which means "to ring," and refers to the perception of an auditory stimulus without an external source of sound (Hazell & Jastreboff, 1990). Tinnitus is commonly classified as "objective" or "subjective." Objective tinnitus refers to sounds that are produced in or close to the auditory system and are in principle audible to an external listener. They may be related to vascular disorders, otoacoustic emissions, or tensor tympany syndrome. (As in other chapters, italics on first use of a term in text indicate that the term is included in the glossary at the chapter's end.) It is often possible to identify the underlying cause and thus cure the problem. Subjective tinnitus is only audible to the patient and may be related to hearing loss, noise exposure, or Menière's disease. The objective– subjective distinction has been criticized, because tinnitus is always a subjective experience and always has a physiological correlate, even if the sounds the patient hears are not directly audible or measurable by an outside observer. In addition, vascular tinnitus can often only be heard by the person with tinnitus.
In only a small proportion of tinnitus cases can an internal source of the sound be identified (see below). In most cases, the perception of tinnitus cannot be explained by an abnormality in the auditory pathways. Tinnitus affects about 35–45% of the population at some point in their lives; however, only about 1–2% experience major interference and seek medical attention (Kirsch, Blanchard, & Parnes, 1989; Nadol, 1993; Parving, Hein, Suaducani, Ostri, & Gyntelberg, 1993; Schleuning, 1991). There are about 1.7–3.4 million persons with severe tinnitus in the United States, and more than 800,000 are seriously disabled by it. Although it affects people of any age, most persons with tinnitus are age 40 or older. There is no gender difference. When the tinnitus becomes chronic, it usually lasts forever. Tinnitus can be described as constant or intermittent; it can affect both ears or be unilateral; it can be similar to a pure tone or can be "noisiform" and take on many characteristics, such as "whistling, ringing, roaring, humming, buzzing, static, whooshing, chirping, like running water, among others, or combinations of these noises" (Ince, Greene, Alba, & Zaretsky, 1987, p. 175). Tinnitus is often associated with "hyperacusis," which is an "exceptionally acute sense of hearing … used to denote a painful sensitiveness to sounds" (Dorland's Illustrated