Frequency-compression outcomes in listeners with steeply sloping audiograms

Previous investigation of an experimental, wearable frequency-compression hearing aid revealed improvements in speech perception for a group of listeners with moderately sloping audiograms (Simpson et al, 2005). In the frequency-compression hearing aid, high frequencies (above 1600 Hz) were amplified in addition to being lowered in frequency. Lower frequencies were amplified without frequency shifting. In the present study, an identical frequency-compression scheme was evaluated in a group of seven subjects, all of whom had steeply sloping hearing losses. No significant differences in group mean scores were found between the frequency-compression device and a conventional hearing instrument for understanding speech in quiet. Testing in noise showed improvements for the frequency-compression scheme for only one of the five subjects tested. Subjectively, all but one of the subjects preferred the sound quality of the conventional hearing instruments. In conclusion, the experimental frequency-compression scheme provided only limited benefit to these listeners with steeply sloping hearing losses. Sumario Las investigaciones previas sobre un auxiliar auditivo experimental con compresión de frecuencia revelaron una mejor percepción del lenguaje en un grupo de oyentes con audiogramas de pendiente moderada (Simpson y col., 2005). En el auxiliar auditivo con compresión de frecuencia, las frecuencias agudas (por encima de 1600Hz) se amplificaron además de ser reducidas en frecuencia. Las frecuencias más graves fueron amplificadas sin cambio en la frecuencia. En el presente estudio, un esquema similar de compresión de frecuencia fue evaluado en un grupo de 7 sujetos, todos los cuales tenían hipoacusia con pendientes abruptas. No se encontraron diferencias significativas en los puntajes medios de grupo para entender el lenguaje en silencio entre el dispositivo con compresión de frecuencia y el instrumento convencional. La evaluación en ruido mostró mejoría para el esquema de compresión de la frecuencia en sólo uno de los cinco sujetos evaluados. Subjetivamente, todos menos uno de los sujetos, prefirieron la calidad del sonido de los instrumentos auditivos convencionales. En conclusión, el esquema experimental de compresión de frecuencia aportó sólo un beneficio limitado para los oyentes con hipoacusias de pendiente abrupta.

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