Auditory training in patients with unilateral cochlear implant and contralateral acoustic stimulation

It was hypothesized that auditory training would allow bimodal patients to combine in a better manner the low-frequency acoustic information provided by a hearing aid with the electric information provided by a cochlear implant, thus maximizing the benefit of combining acoustic (A) and electric (E) stimulation (EAS).

Performance in quiet or in the presence of a multitalker babble at +5 dB signal to noise ratio was evaluated in seven bimodal patients before and after auditory training. The performance measures comprised identification of vowels and consonants, consonant-nucleus-consonant words, sentences, voice gender, and emotion. Baseline performance was evaluated in the A-alone, E-alone, and combined EAS conditions once per week for 3 weeks. A phonetic-contrast training protocol was used to facilitate speech perceptual learning. Patients trained at home 1 hour a day, 5 days a week, for 4 weeks with both their cochlear implant and hearing aid devices on. Performance was remeasured after the 4 weeks of training and 1 month after training stopped.

After training, there was significant improvement in vowel, consonant, and consonant-nucleus-consonant word identification in the E and EAS conditions. The magnitude of improvement in the E condition was equivalent to that in the EAS condition. The improved performance was largely retained 1 month after training stopped.

Auditory training, in the form administered in this study, can improve bimodal patients' overall speech understanding by improving E-alone performance.