Tinnitus
Many people who come for hearing testing experience tinni- tus, the sensation of hearing internal sounds when no sound is present (see Chapter 35). Tinnitus can interfere with the perception of test tones, which can lead to a large number of false-positive responses, and false-positive responses can produce an inaccurate (too sensitive) threshold estimation. Some listeners simply require additional instruction and encouragement to wait until they are more certain they have heard a test tone. In some cases, the audiologist can pres- ent a clearly audible tone at the test frequency to remind the listener of the test tone. For more intractable cases, the examiner can present a series of pulsed tones and ask the listener to count the number of tones. It is important with listeners who are giving false-positive responses to avoid a fixed presentation rhythm and to provide irregular intervals of “no trial” silence to confirm that their responses are, in fact, responses to test tones.
In rare cases, patients have tinnitus resulting from blood flowing nearby auditory structures. Blood flowing through a vein or artery sometimes produces masking noise or “bruit” that can elevate thresholds for low-frequency tones (Champlin et al., 1990). On the audiogram, this form of tinnitus may produce an apparent sensory/neural loss. The loss occurs because the tinnitus masks AC and BC thresh- olds. Bruit, a recordable form of tinnitus resulting from vibrations in the head or neck, is documented by audiolo- gists by measuring sound levels in the ear canal (Champlin et al., 1990). This problem is treatable when the problem is caused by a vein. In a case study reported by Champlin et al. (1990), the patient received some reduction in tinnitus loudness before surgery by applying pressure to her neck. Surgical ligation of the vein responsible for the tinnitus was shown to be an effective treatment. Surgery reduced tinnitus loudness, SPLs of the bruit measured in the ear canal were lower, and the audiogram showed significantly improved thresholds.
In rare cases, patients have tinnitus resulting from blood flowing nearby auditory structures. Blood flowing through a vein or artery sometimes produces masking noise or “bruit” that can elevate thresholds for low-frequency tones (Champlin et al., 1990). On the audiogram, this form of tinnitus may produce an apparent sensory/neural loss. The loss occurs because the tinnitus masks AC and BC thresh- olds. Bruit, a recordable form of tinnitus resulting from vibrations in the head or neck, is documented by audiolo- gists by measuring sound levels in the ear canal (Champlin et al., 1990). This problem is treatable when the problem is caused by a vein. In a case study reported by Champlin et al. (1990), the patient received some reduction in tinnitus loudness before surgery by applying pressure to her neck. Surgical ligation of the vein responsible for the tinnitus was shown to be an effective treatment. Surgery reduced tinnitus loudness, SPLs of the bruit measured in the ear canal were lower, and the audiogram showed significantly improved thresholds.
References, Handbook of Clinical Audiology