Is intratympanic injection of erdosteine protective against cisplatin-induced ototoxicity?

Cisplatin induces ototoxicity in adult and pediatric population. Our aim was (1) to assess the protective effect of intratympanic injections of erdosteine in the prevention of cisplatin-induced ototoxicity and (2) to investigate inner ear protection using a scanning electron microscope. Ears of 20 Hartley guinea pigs were assigned to four subgroups and received an intratympanic injection of: E1-erdosteine 1.125 mg/cc, NS-normal saline, E2-erdosteine 2.25 mg/cc and E4-erdosteine 4.5 mg/cc. After 45 min, an intraperitoneal cisplatin injection of 3 mg/kg was performed and repeated 8 times, once a week to achieve 24 mg/kg. Auditory brainstem responses were recorded before any injection and after 24 mg/kg of cisplatin for the frequencies 1, 2, 4, 6 and 8 kHz. Cochleas were analyzed under scanning electron microscope. Average hearing loss in the NS subgroup was 29.8 dB which was lower than E1, E2 and E4 subgroups (40, 43.9, and 51.7 dB, respectively). Difference in the mean threshold increase was statistically significant between NS and the three erdosteine subgroups (P < 0.03). No difference was identified between E1 and E2 (P > 0.05). However, difference was significant between E1 and E4 (P < 0.02) and between E2 and E4 (P < 0.03); Electron microscopy revealed almost complete destruction of the stereocilia of the outer hair cells in all subgroups (NS, E1, E2 and E4). The ears treated with erdosteine showed a diffuse inflammatory reaction and osteitis of the middle ear. Low or high concentration of intratympanic erdosteine does not offer protection against cisplatin-induced ototoxicity as it causes a considerable inflammatory reaction.

Bone anchored hearing aid in single sided deafness: outcome in right-handed patients.

OBJECTIVE: To assess the benefits in terms of sound localization, to evaluate speech discrimination in noise, to appraise the prosthesis benefit and to identify outcome in right and left handed patients when BAHA are implanted on the right or on the left deaf side. METHODS: Two years prospective study in a tertiary referral center. Tests consist on Hearing in Noise Test (HINT) and sound localization after 6 months of BAHA use. Quality of life was assessed by the Abbreviated Profile of Hearing Aid Benefit (APHAB) questionnaire. The paired T-test and the analysis of variance were used for the statistical measures. RESULTS: Twenty-one subjects participated in this study. HINT: patients score better when speech and noise are spatially separated and noise is not presented to the healthy ear. In the right-handed group (left dominant brain), unaided left-implanted patients performed better than right-implanted patient when speech is in front and noise to the good ear; when speech is presented to the good ear and noise to the front, aided right-implanted patients performed better than aided left-implanted patients. Sound localization: correct answers attain 35% at best. No statistical difference between the frequencies was found, neither between the left and right implanted patients. APHAB: the score improvement is statistically significant for the global score, the background noise subscale at 5 weeks and for the reverberation subscale at 6 months. CONCLUSION: It seems that left dominant hemisphere is able to filter crossed noise better than the right hemisphere. Results of uncrossed speech to the dominant left brain are better than the uncrossed speech to the non-dominant right brain.

Are intratympanic injections of N-acetylcysteine and methylprednisolone protective against Cisplatin-induced ototoxicity?

OBJECTIVE: To identify and to compare the protective effect of intratympanic injections of N-acetylcysteine (NAC) or methylprednisolone to prevent cisplatin-induced ototoxicity, to investigate inner ear protection using an electron microscope and to evaluate the effect of 4% NAC on the middle ear. DESIGN: Experimental study. SETTING: Basic ear research center at Sainte-Justine hospital. METHODS: Ten Hartley guinea pigs were divided into two groups, according to the product used intratympanically (4% NAC or 62.5 mg/mL methylprednisolone) in one ear. The other ear was left as control. Cisplatin was administered intraperitoneally (3 mg/kg), once a week for 5 weeks. MAIN OUTCOME MEASURES: Auditory evoked brainstem responses were used to test hearing. The inner ear was screened using an electron microscope. RESULTS: Significant threshold shift was seen on all tested frequencies of both groups. This difference is clinically and statistically significant in the methylprednisolone group. The NAC-treated group had a lower threshold shift than the methylprednisolone group in both ears. Electron microscope studies showed in all untreated-NAC ears severe lesion of the inner and outer hair cells with complete degeneration of steriocilia, whereas in NAC-treated ears we noted a nuclear and cytoplasmic membrane preservation with some preservation of steriocila. Also, 4% intratympanic NAC produces an external auditory canal and middle ear inflammatory reaction. CONCLUSIONS: Intratympanic injections of methylprednisolone failed to demonstrate efficacy in protecting cisplatin ototoxicity whereas 4% NAC showed a partial protection. The safety of intratympanic injections should be investigated in further studies, as possible systemic shift of the locally administered treatment is suspected.

How much residual hearing is 'useful' for music perception with cochlear implants?

AIM: To compare performance on a song recognition task of bilaterally combined electric and acoustic hearing (bimodal stimulation) with electric or acoustic hearing alone. METHODS: Subjects were 14 adults with cochlear implants (CI) who continued to use a hearing aid (HA) in one/both ears. Subjects were asked to identify excerpts from 15 popular songs, which were familiar to them, presented in a random order via a single loudspeaker. Presentation conditions were fixed in order: bimodal, CI alone and then HA alone. Musical excerpts were presented in each condition with and then without lyrics. RESULTS: In a subgroup of subjects (n = 8) with better low-frequency residual hearing (thresholds <85 dB hearing level (HL)), mean scores for bimodal stimulation were significantly greater than for CI alone. In addition, mean 'no lyrics' scores for HA alone (59.7%) were significantly greater than for CI alone (38.8%). All of these subjects considered bimodal stimulation to be the most enjoyable way to listen to music. For the remaining subjects (n = 6) there was no benefit from using bimodal stimulation over CI alone, and the majority of these preferred to listen to music using CI alone. CONCLUSIONS: Bimodal stimulation provides better perception of popular music, particularly melody recognition, compared to CI alone when low-frequency residual hearing is better than 85 dB HL.