The benefits of combining acoustic and electric stimulation for the recognition of speech, voice and melodies

Abstract

Fifteen patients fit with a cochlear implant in one ear and a hearing aid in the other ear were presented with tests of speech and melody recognition and voice discrimination under conditions of electric (E) stimulation, acoustic (A) stimulation and combined electric and acoustic stimulation (EAS). When acoustic information was added to electrically stimulated information performance increased by 17-23 percentage points on tests of word and sentence recognition in quiet and sentence recognition in noise. On average, the EAS patients achieved higher scores on CNC words than patients fit with a unilateral cochlear implant. While the best EAS patients did not outperform the best patients fit with a unilateral cochlear implant, proportionally more EAS patients achieved very high scores on tests of speech recognition than unilateral cochlear implant patients.

(c) 2007 S. Karger AG, Basel

Figures

Fig. 1

Mean audiogram for 15 patients with low-frequency residual hearing.

Fig. 2

Mean scores and standard deviations for E, A and EAS conditions. Significant differences among conditions are indicated, e.g., E > A, for each type of test material. a CNC words. b Consonants. c Vowels. d Sentences – quiet. e Sentences +10 dB SNR. f Sentences +5 dB SNR.

Fig. 3

Mean scores and standard deviations for E, A and EAS conditions. Significant differences among conditions are indicated, e.g., E > A, for each type of test material. a Melodies. b Voice – within. c Voice – between.

Fig. 4

Percent correct CNC words for conventional implant patients in Helms et al. [1997] and for the patients in the current study using E and EAS stimulation. Each dot indicates the performance of a single patient. Group mean scores are indicated by a horizontal line.

Fig. 5

Percent correct scores for patients, fit with conventional cochlear implants, who scored 50% correct or better on CNC words (average and above) and for patients in the current study using EAS. Each dot indicates the performance of a single patient. a CNC words. b Consonants. c Vowels. d Sentences – quiet. e Sentences +10 dB SNR. f Sentences +5 dB SNR.

Fig. 6

Percent correct scores for patients, fit with conventional cochlear implants, who scored 50% correct or better on CNC words (average and above) and for patients in the current study using EAS. Each dot indicates the performance of a single patient. a Melody recognition. b Voice – within. c Voice – between.