Competing noise interferes with comprehension of connected speech for most cochlear implant patients.

Surgical implantation of a multichannel cochlear prosthesis has become a widespread treatment for profound hearing loss. The relationship between duration of hearing loss and speech recognition ability was examined in 20 postlinguistically deafened adults using the Nucleus 22-Channel Cochlear Prosthesis. Data analysis indicated statistically significant negative correlations between duration of profound hearing loss and postoperative performance on the Central Institute for the Deaf Everyday Sentence Test and the Northwestern University Monosyllabic Word Test (NU-6). Age at implantation and age at onset of profound hearing loss were not found to be significantly correlated with performance on the two measures. These findings are discussed in terms of patient counseling and prediction of potential benefit to the patient.

A series of 73 postlinguistically deafened adults and 34 prelinguistically deafened children were evaluated with the Spectral Peak (SPEAK) coding strategy of the Nucleus 22-channel cochlear implant. The adults who received consecutive implants demonstrated rapid acquisition of open-set speech recognition skills in the initial postoperative period. Group mean sentence recognition improved to 53.5% (n = 52) after 2 weeks, 62.1% (n = 55) after 1 month, 69.8% (n = 57) after 3 months, and 74.4% (n = 42) after 6 months of use. At the 6-month evaluation interval, 43% of subjects scored greater than 90% on sound-alone sentence recognition in quiet and only one patient (2.4%) scored less than 10%. Mean monosyllabic word recognition was 35.6% after 6 months of use. The 34 prelinguistically deafened children were converted from the Multipeak strategy to Spectral Peak strategy at four large pediatric implant centers. After 6 months of using the new coding strategy, the children demonstrated significant improvements in their speech perception abilities.

This study demonstrates that important learning occurs during the first several weeks of cochlear implant use, making it difficult to adequately compare performance with different speech processing strategies. However, the finding that patients often prefer the strategy they understand speech the best with supports the clinical practice of letting adult patients select their preferred strategy without formally evaluating speech perception with each available strategy.

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