Are There Cochlear Dead Regions Involved in Hearing Loss after Cisplatin Ototoxicity?

BACKGROUND: The most common complaint of patients affected by chemotherapy-induced hearing loss is difficulty understanding speech in noisy environments despite the use of hearing aids. Cochlear dead regions, those areas with damaged or absent inner hair cells and dendrites, may account for this type of hearing loss. However, it is unknown whether this condition is associated with cisplatin agents. OBJECTIVE: The aim of this study was to determine whether cisplatin is associated with hearing loss and cochlear dead regions. METHODS: This prospective cross-sectional study was conducted in patients participating in routine audiological monitoring during and after chemotherapy treatment. Adults undergoing audiological evaluation who had completed chemotherapy treatment were invited to participate. Patients were divided into 3 groups according to pure tone thresholds. Group 1 patients had thresholds over 70 dB (HL) at 2,000 Hz and higher frequencies. Group 2 patients had thresholds below 70 dB (HL) up to 2,000 Hz. Patients in the control group had normal thresholds at all frequencies. The threshold equalizing noise test (TEN[HL]) was used to identify cochlear dead regions by repeating thresholds in the presence of TEN noise played from a compact disc. The presence of cochlear dead regions was established when the masked threshold was 10 dB or greater above the TEN level and 10 dB or greater above the absolute threshold at any frequency. RESULTS: Twelve patients were included in study group 1, 10 patients in study group 2, and 7 patients in the control group. Cochlear dead regions were present in all patients with hearing loss and in none of the control group. For groups 1 and 2, mean differences between absolute and masked thresholds were 21 and 16 dB at 500 Hz; 22 and 15 dB at 1,000 Hz; 31 and 17 dB at 2,000 Hz; 32 and 20 dB at 3,000 Hz; and 31 and 21 dB at 4,000 Hz, respectively. Nevertheless, analysis of variance testing with Bonferroni analysis showed a difference between groups 1 and 2 only at 2,000, 3,000, and 4,000 Hz. CONCLUSION: We found unresponsive or dead cochlear regions in patients who had undergone cisplatin chemotherapy even among patients with mild to moderate hearing loss.

Evaluation of ototoxicity in children treated for retinoblastoma: preliminary results of a systematic audiological evaluation.

BACKGROUND: The objective of this study was to identify the ocurrence of hearing loss in children treated for retinoblastoma using a multidisciplinary approach. PATIENTS AND METHODS: Thirty-two children were evaluated pre- and post-treatment. Eleven children were treated exclusively with enucleation, fifteen with carboplatin and six with cisplatin. Otoacoustic emissions were performed with the ILO 88, before and after the treatment. RESULTS: In our study we found 5 children (24%) with hearing loss among the 21 evaluated. However in the group of children treated with carboplatin (N=15), 1 case (6.6%) presented hearing loss, while among those treated with cisplatin (N=6) we found 4 cases (66.6%) with hearing loss (p=0.0114). CONCLUSION: We concluded that patients who are treated with cisplatin are at risk for developing hearing loss.

Hearing loss and complaint in patients with head and neck cancer treated with radiotherapy.

OBJECTIVE: To investigate occurrences of hearing loss and hearing complaints among patients with head and neck tumors who underwent radiotherapy. DESIGN: Prospective case-control study. SETTING: Tertiary care hospital. PARTICIPANTS: Two hundred eighty-two participants underwent evaluation, including 141 with head and neck tumors and 141 as an age-matched control group. The controls had never undergone oncological treatment that put their hearing at risk. MAIN OUTCOME MEASURES: Results of audiological evaluation, including the Hearing Handicap Inventory for the Elderly questionnaire and pure-tone, speech, and immittance audiometry, and radiation dose received by the auditory system (based on the percentage of the external auditory canal included in the radiation field). RESULTS: We observed occurrences of hearing loss in 102 (72.3%) of the participants exposed to radiotherapy and 69 (48.9%) of the control group (P < .001). Hearing losses were mostly sensorineural and of mild degree, but those exposed to radiotherapy more frequently presented with severe and mixed-type hearing losses (P < .001). Of the participants exposed to radiotherapy, 19.1% had a severe handicap (P < .001). CONCLUSION: Patients undergoing radiotherapy in the head and neck region have a higher incidence of hearing loss and more severe hearing handicap. Trial Registration  clinicaltrials.gov Identifier: NCT01102621.