RESUMEN
Effects of frequency-shifted feedback are typically examined using Eventide Harmonizer Series processors to shift the fundamental frequency (F0) of auditory feedback during vocalizations, eliciting compensatory shifts in speaker F0. Recently, unexpected intensity changes were observed in speakers' ear canals, corresponding with F0 shifts. An investigation revealed that feedback time delays introduced by the processor resulted in phase shifts between feedback and unprocessed voice signals radiating into the ear canal via bone conduction, producing combination waves with gains as high as 6 dB. Shifts of this magnitude potentially alter the interpretation of previously published results and should be controlled in future studies.
Asunto(s)
Conducto Auditivo Externo/fisiología , Retroalimentación Psicológica , Mecanotransducción Celular , Personas con Deficiencia Auditiva/psicología , Acústica del Lenguaje , Percepción del Habla , Voz , Estimulación Acústica , Adulto , Umbral Auditivo , Implantación Coclear , Femenino , Humanos , Masculino , Persona de Mediana Edad , Personas con Deficiencia Auditiva/rehabilitación , Espectrografía del Sonido , Medición de la Producción del Habla , Factores de Tiempo , Adulto JovenRESUMEN
PURPOSE: To assess the Computerized Revised Token Test (CRTT) performance of individuals with normal hearing under several intensity conditions and under several spectral and temporal perturbation conditions. METHOD: Sixty normal-hearing listeners were randomly assigned to 1 of 3 groups. Group 1 provided performance-intensity information about CRTT performance using uncompressed acoustic stimuli. Groups 2 and 3 completed the CRTT using temporally and spectrally compressed and expanded stimuli. CRTT performance functions were plotted for each group. RESULTS: Group 1 required minimal audibility to perform maximally on this task. As expected, Groups 2 and 3 showed significant differences across subtests, regardless of distortion condition. Mean differences in performance between successive conditions for Group 2 increased beyond 40% time compressed. There was 1 significant difference for the time-expanded condition. There were no differences across frequency compressed and expanded conditions. CONCLUSION: Young listeners require limited signal gain on the CRTT to achieve maximum performance. Time and frequency compression and expansion results were consistent with previous findings with varying types of speech stimuli. The results have implications for administration and interpretation of the CRTT administered to persons from other populations and will help in the development of a normative database for the CRTT.