RESUMO
Early- and middle-component-averaged electroencephalic responses (AER) to monotic clicks at 60, 40 and 20 dB normal hearing level were elicited from 18 carefully selected normal neonates. Grand-composite AERs of the responses from all 18 babies showed stimulus-related configurations at all three stimulus levels. AERs for individual babies were more frequently identified as stimulus-related when poststimulus activity beyond 10 ms was included in response-identification procedures than when only the first 10 ms was observed.
Assuntos
Transtornos da Audição/diagnóstico , Testes Auditivos/métodos , Audiometria , Eletroencefalografia , Humanos , Recém-Nascido , Doenças do Recém-Nascido/diagnóstico , Programas de RastreamentoRESUMO
Auditory masking generated by two-tone complexes centered around 7 000 Hz was measured in 10 young adults with normal hearing sensitivity as a function of the frequency separation (deltaf) and SPL of the masker's components. Remote masking (1) was evident for test signals in the frequency region corresponding to the masker's deltaf; (2) increased with masker SPL, but at a rate less than that usually observed when lower frequency bands of noise are used as maskers, and (3) was relatively constant in magnitude for a given SPL as a function of the masker's deltaf. The masking produced in low-frequency regions by high-frequency two-tone complexes adds support to the hypothesis that remote masking is primarily a result of aural distortion.
Assuntos
Percepção Auditiva/fisiologia , Mascaramento Perceptivo/fisiologia , Estimulação Acústica , Adulto , Limiar Auditivo , Feminino , Humanos , MasculinoRESUMO
One ear of each of seven normal-hearing subjects was exposed to a continuous 1000-Hz tone at 110 dB SPL for three minutes. During exposure, a broad-band noise at 100 dB SPL was presented to the contralateral ear. The noise was either continuous or pulsed. Four pulsed conditions employed repetition periods of 360, 180, 90, or 9 msec with a 50% duty cycle. A control condition in which no noise was presented was also included. Temporary threshold shift was measured at selected postexposure times at the frequency one-half octave above the exposure frequency. TTS2 was greatest for the control condition and least for the 360- and 180-msec conditions. Results are discussed in relation to the dynamics of the acoustic reflex, particularly reflex relaxation, reflex adaptation, and reflex temporal summation.