RESUMO
Purpose The purpose of this study was to characterize spatial hearing abilities of children with longstanding unilateral hearing loss (UHL). UHL was expected to negatively impact children's sound source localization and masked speech recognition, particularly when the target and masker were separated in space. Spatial release from masking (SRM) in the presence of a two-talker speech masker was expected to predict functional auditory performance as assessed by parent report. Method Participants were 5- to 14-year-olds with sensorineural or mixed UHL, age-matched children with normal hearing (NH), and adults with NH. Sound source localization was assessed on the horizontal plane (-90° to 90°), with noise that was either all-pass, low-pass, high-pass, or an unpredictable mixture. Speech recognition thresholds were measured in the sound field for sentences presented in two-talker speech or speech-shaped noise. Target speech was always presented from 0°; the masker was either colocated with the target or spatially separated at ±90°. Parents of children with UHL rated their children's functional auditory performance in everyday environments via questionnaire. Results Sound source localization was poorer for children with UHL than those with NH. Children with UHL also derived less SRM than those with NH, with increased masking for some conditions. Effects of UHL were larger in the two-talker than the noise masker, and SRM in two-talker speech increased with age for both groups of children. Children with UHL whose parents reported greater functional difficulties achieved less SRM when either masker was on the side of the better-hearing ear. Conclusions Children with UHL are clearly at a disadvantage compared with children with NH for both sound source localization and masked speech recognition with spatial separation. Parents' report of their children's real-world communication abilities suggests that spatial hearing plays an important role in outcomes for children with UHL.
Assuntos
Perda Auditiva Unilateral , Localização de Som , Percepção da Fala , Adulto , Criança , Audição , Testes Auditivos , Humanos , Mascaramento PerceptivoRESUMO
Purpose: The purpose of this study was to evaluate the impact of code-switching on Spanish/English bilingual listeners' speech recognition of English and Spanish words in the presence of competing speech-shaped noise. Method: Participants were Spanish/English bilingual adults (N = 27) who were highly proficient in both languages. Target stimuli were English and Spanish words presented in speech-shaped noise at a -14-dB signal-to-noise ratio. There were 4 target conditions: (a) English only, (b) Spanish only, (c) mixed English, and (d) mixed Spanish. In the mixed-English condition, 75% of the words were in English, whereas 25% of the words were in Spanish. The percentages were reversed in the mixed-Spanish condition. Results: Accuracy was poorer for the majority (75%) and minority (25%) languages in both mixed-language conditions compared with the corresponding single-language conditions. Results of a follow-up experiment suggest that this finding cannot be explained in terms of an increase in the number of possible response alternatives for each picture in the mixed-language condition relative to the single-language condition. Conclusions: Results suggest a cost of language mixing on speech perception when bilingual listeners alternate between languages in noisy environments. In addition, the cost of code-switching on speech recognition in noise was similar for both languages in this group of highly proficient Spanish/English bilingual speakers. Differences in response-set size could not account for the poorer results in the mixed-language conditions.