RESUMEN
Speech sound discrimination thresholds were obtained for two speech sound contrasts (/ba/ vs. /da/ and /ba/ vs. /ga/) for infant and adult subjects. The stimuli were computer-generated synthetic tokens. An adaptive (one-up, one-down) threshold procedure was used with the visual reinforcement infant speech discrimination procedure for the infant subjects. Adults were tested using the same apparatus and threshold-tracking protocol as the infants. There was a 28-dB difference in threshold for discrimination of /ba/ versus /da/ and a 25-dB difference in threshold for discrimination of /ba/versus/ga/ between the infants and the adults. The differences reveal that to reach a criterion level of performance on a simple speech perception task, infants require much greater stimulus intensity than do adults. This has implications for our understanding of normal auditory development, for our notions of hearing impairment in infants and for the role of intensity in research studies of infant speech perception.
Asunto(s)
Umbral Auditivo , Enmascaramiento Perceptual , Fonética , Pruebas de Discriminación del Habla , Prueba del Umbral de Recepción del Habla , Adolescente , Adulto , Atención , Femenino , Humanos , Lactante , Masculino , Valores de Referencia , Percepción del HablaRESUMEN
We studied 109 children with otitis media with effusion of 2 months' duration or longer that was unresponsive to medical management. Eighty-six subjects who had neither "significant" hearing loss nor defined symptoms were randomly assigned to receive myringotomy, myringotomy with tympanostomy tube insertion, or no surgery, and 23 subjects with significant hearing loss, defined symptoms, or both were randomly assigned to receive either myringotomy or myringotomy with tube insertion. Myringotomy with tube insertion provided more disease-free time and better hearing than either myringotomy alone or no surgery; however, some subjects who underwent myringotomy with tube insertion developed otorrhea or persistent perforation of the tympanic membrane. Myringotomy offered no advantage over no surgery regarding percent of time with middle-ear effusion, number of acute otitis media episodes, and number of subsequent surgical procedures. These results may not properly be extrapolated to less severely affected children.
Asunto(s)
Ventilación del Oído Medio , Otitis Media con Derrame/cirugía , Membrana Timpánica/cirugía , Pruebas de Impedancia Acústica/efectos adversos , Pruebas de Impedancia Acústica/métodos , Audiometría de Tonos Puros , Niño , Preescolar , Enfermedad Crónica , Enfermedades del Oído/etiología , Estudios de Seguimiento , Pérdida Auditiva/epidemiología , Humanos , Lactante , Ventilación del Oído Medio/efectos adversos , Otitis Media con Derrame/fisiopatología , Distribución Aleatoria , RecurrenciaRESUMEN
The binaural masking level difference (MLD) was measured at multiple masking levels (i.e. 500 Hz narrow band noise presented at 50-100 dB overall SPL) in normal hearing subjects and clinical subjects with varying types and degrees of hearing loss. MLD versus noise level (MLD-NL) functions then were derived for each subject. Some growth in the MLD-NL was seen in nearly all cases of hearing loss up to 70 dB in the poorer ear. These findings suggest that the MLD-NL function may provide the basis for extending the diagnostic usefulness of the MLD test in cases of substantive hearing loss.