2021 Volume 64 Issue 6 Pages 331-338
Although high-frequency hearing loss, as typified by age-related hearing loss, accounts for a large percentage of cases of hearing disorders, high-frequency hearing loss does not cause much inconvenience in conversation. Therefore, tinnitus as a symptom of hearing loss is the most common complaint of patients with high-frequency sensorineural hearing loss when they visit an otorhinolaryngologist, as their hearing is close to normal in the low to mid frequency range. Cisplatin, an anticancer drug used in the treatment of many malignancies, is well-known as a cause of sensorineural hearing loss of the high-frequency type. Although the incidence of sensorineural hearing loss increases when the cumulative dose of cisplatin exceeds 300 mg/m2, hearing impairment can occur even with smaller cumulative doses of cisplatin. In this study, we report the case of a patient who developed tinnitus during adjuvant chemotherapy after lung cancer surgery, at a relatively small cumulative dose (160 mg/m2). Pure-tone audiometry showed high-frequency sensorineural hearing loss, and assessment of distortion product otoacoustic emission (DPOAE) showed a decrease in the distortion product level at high frequencies, suggesting the diagnosis of tinnitus associated with cochlear damage caused by cisplatin treatment. The high-frequency distortion-type sensorineural hearing loss progressed with increasing cumulative dose of cisplatin. Both the distortion product level and signal-to-noise ratio of distorted component otoacoustic emissions, which was used to evaluate cochlear damage, were decreased, and the tinnitus handicap inventory (THI) score, which reflects the severity of the subjective symptom of tinnitus, worsened. It is thought that it would be useful to perform not only pure tone audiometry, but also a combination of various other tests including measurement of distortion component otoacoustic emissions and assessment by the tinnitus handicap inventory for a thorough auditory evaluation in patients receiving treatment with cisplatin.
