Temporal fine structure in cochlear implants: preliminary speech perception results in Cantonese-speaking implant users.

CONCLUSION: Acute comparisons between continuous interleaved sampling (CIS) and a temporal fine structure (TFS) coding strategy in Cantonese-speaking cochlear implant (CI) users did not reveal any significant differences in speech perception. Performance with the unfamiliar TFS coding strategy was on a par with CIS. Benefits of extended fine structure use observed in other studies should be investigated for tonal languages. OBJECTIVES: CIS-based stimulation strategies lack an explicit representation of fine structure, which is crucial for tonal language speech perception. The aim of this study was to assess speech recognition with a TFS coding strategy in Cantonese-speaking CI users with no prior fine structure experience. METHODS: The fine structure coding strategy encodes TFS on a few apical channels, while the remaining more basal channels carry CIS stimuli. Twelve MED-EL implantees and long-term CIS users participated in a study comparing recognition for Cantonese lexical tones and CHINT sentences between CIS and fine structure stimulation. RESULTS: Mean tone identification scores in 12 subjects were 59.2% with CIS and 59.2% with fine structure stimulation using 4 TFS channels, mean scores of CHINT sentences in 8 subjects were 54.2% with CIS and 55.9% with TFS stimulation. Differences between the two strategies were not significant for any speech test. Two additional versions of TFS strategy and pulse rates were tested in six subjects. No significant differences between strategies were found.

[Auditory brainstem implantation in patient with bilateral acoustic neuromas].

OBJECTIVE: To restore auditory sensation for patient suffering loss of hearing due to bilateral acoustic neuromas. METHOD: One patient of bilateral acoustic neuromas received auditory brainstem implant (ABI) at the same surgery for resection of the second tumor. The retrosigmoid approach was used for resection of the tumor and to exposure the lateral recess of the fourth ventricle for placement of ABI electrode array. Intraoperative 7th and 9th nerves monitoring and electrically evoked auditory brainstem responses (EABR) were recorded to localize the placement of ABI electrode array. RESULT: Initial ABI switch-on was performed eight weeks after the surgery under close monitoring of vital signs. Auditory sensation was perceived on stimulation of all channels. CONCLUSION: The multichannel ABI could effectively restore auditory sensation for patient deafened by bilateral acoustic neuromas. The accurate location of the cochlear complex during surgery was the critical factor for success of ABI.

ENT management of a child with CHARGE association.

The acronym CHARGE is used to describe specific congenital birth defects in children: colobomata, heart defect, atresia of the choanae, retarded growth or development, genital hypoplasia, and ear anomalies or deafness. CHARGE association with hearing impairment is a challenge to ENT surgeons. We report the case of a child with CHARGE association who underwent cochlear implantation using an unconventional surgical approach and review the postoperative speech perception results. The benefits of cochlear implantation in children with multiple congenital defects are discussed.

Randomized evaluation of the audiologic outcome of ventilation tube insertion for middle ear effusion in patients with nasopharyngeal carcinoma.

OBJECTIVE: Complications after ventilation tube insertion for middle ear effusion in patients with nasopharyngeal carcinoma are frequent. This may compromise the overall benefit obtained from the procedure. This study evaluates the hearing improvement after tube insertion compared with observation alone to see if the benefits of the procedure outweigh its potential complications. DESIGN: Prospective randomized controlled trial. SETTING: Full clinical and emergency otolaryngologic services hospital in an academic institution. METHODS: Patients with nasopharyngeal carcinoma and middle ear effusion were randomized for preradiotherapy ventilation tube insertion or observation. Audiologic assessment with a pure-tone audiogram was performed before the procedure, after ventilation tube insertion, and at fixed intervals after irradiation. Audiologic outcome was compared between the two groups. MAIN OUTCOME MEASURE: Air-conduction threshold and air-bone gap on a pure-tone audiogram at different intervals after radiotherapy. RESULTS: There was no significant difference in hearing threshold changes between the two groups for up to 4 years. Both groups had air-bone gap improvement following radiotherapy and the improvement was not significantly different between the two groups. The proportion of patients with closure of the air-bone gap on follow-up was not different between the two groups. CONCLUSIONS: Ventilation tube insertion before radiotherapy did not offer additional hearing benefit when compared with observation alone. The procedure had no deleterious effect on hearing for up to 4 years.