Effect of the Frequency Allocation Table in the Speech Processor Upgraded

Introduction: The new frequency allocation tables (FAT) were developed for cochlear implant users, some patients may have good results with new tables, but it is possible that others do not adapt and degraded the performance of speech perception.

Objective: To identify the effect of the FAT of the Freedom speech processor to the patients implanted with Nucleus 22.

Methods: Seventeen experienced patients, ranging from 15 to 82 years, without previous experience with the new technology were selected. Two maps were created with different FAT, the converted maps used the same table that the old processor, except the limit of high frequency. The upgraded maps used a new table ranged from 188 to 7,938 Hz. After the programming of the two maps, the perception of vowels and monosyllabic words were performed. The audiometric thresholds were tested both speech processor.

Results: Eleven patients maintained the map that had been used with the Spectra, but only three patients were possible to maintain the same FAT and performance better in all tests. Eight patients were maintaining the limit on the low frequency at 120 Hz, but the high-frequency limit of 8,658 Hz was changed to 7,938 Hz. In this case, we observed better performed on monosyllables test and the worst threshold at 8,000 Hz. Six patients preferred the upgraded map, and three of all performed better in monosyllables when the high frequency was increased.

Conclusions: Most of the patients (64.7%) retained the original FAT, showing the importance to maintaining the characteristics and preferences used by the patient.