Evaluation and selection of maskers and other devices used in the treatment of tinnitus and hyperacusis.

Abstract

For more than two decades there has been a significant increase in the number and quality of studies investigating the phenomenon of subjective tinnitus. We mention subjective tinnitus because it is, by far, the most prevalent. Subjective tinnitus may be defined as the perception of an acoustic-like sensation for which there is no external generation. Objective tinnitus (vibratory tinnitus), on the other hand, is an acoustic-like sensation that can be heard by others and lends itself to physical measurement. Chronic myoclonus (chronic spasm of a muscle or of a group of muscles) involving the tensor tympani, stapedius and palatine muscles (referring to the palate), blood flow turbulence, and movement involved in the opening of the Eustachian tube are conditions that can cause objective tinnitus. Perhaps, one may include otoacoustic emissions as a form of objective tinnitus. This review will concern itself primarily with the rationale underlying the use of masker devices, hearing aids and other noise generating systems used in the treatment of subjective tinnitus. We review not only the phenomenon of tinnitus masking, but also discuss the use of controlled levels of noise in the treatment of hyperacusis, an exaggerated or abnormal intolerance to ordinary sounds in one's acoustic environment. In so doing, the emphasis is placed on the reader's understanding of each of the disorders, not only in terms of an applied external, acoustic stimulus but also of the individual's behavioral response to his or her malady. There are four messages for those contemplating the provision of clinical service to patients with subjective tinnitus. First, there is no consensus regarding the etiology of this perplexing disorder. Second, there is no known “cure” for subjective tinnitus. Third, there is no single therapeutic modality sufficiently compelling to warrant its use above all others. We are not suggesting individuals cannot be helped with some form of therapeutic intervention, including masker devices, but rather that there is much to be learned about the neurophysiological generation of subjective tinnitus and the psychodynamics of those who are suffering from it. Fourth, there is enough intellectual and clinical challenge in the treatment of subjective tinnitus to warrant the interest and active involvement of audiologists. Those working with the tinnitus patient deal with the symptoms of the disorder. The clinician can control to some extent the patient's awareness of the ongoing tinnitus through the use of masker or noise generating instrument(s), but can do nothing to affect a cure. To cure this perplexing problem, a way must be found to suppress the tinnitus generator(s), whatever it (they) may be, and thereby alter the abnormal neural activity which gives rise to its perception. The understanding of tinnitus and its treatment has advanced to that point where it is no longer necessary, or prudent, for the physician or any other health practitioner to advise the patient to “learn to live with it.” We say this, because there are a number of therapeutic approaches which have proven of significant benefit to the tinnitus patient, including masker and noise generating devices. Our task here is to review therapeutic practices and patient management strategies related to the use of masker devices and other noise generating systems. This review will include not only traditional masking, wherein the intent is to cover an aversive sound with a neutral one, but it will also discuss the use of combination hearing aid-masker instruments and masking tinnitus with hearing aids. Finally, it will consider retraining therapy, which has the intent not of covering the sound but rather of retraining the brain to ignore the sound so that it is no longer an issue in the patient's life.