Abstract
A dead region (DR) is a region of the cochlea where there are no functioning inner hair cells and/or neurones. We compared the edge frequencies, fe, of DRs estimated using four methods: the TEN(HL) test; psychophysical tuning curves (PTCs) measured in simultaneous masking (320-Hz wide noise masker) using a ‘fast’ method (sweeping masker) and a ‘classical’ method; and PTCs measured in forward masking (sinusoidal masker) using a ‘classical’ method. Fourteen subjects with high-frequency DRs were tested. For measurement of PTCs, the signal frequency was chosen to fall inside the DR; the tip frequencies of the PTCs were taken as indicating the values of fe. The values of fe obtained from the PTCs in forward and simultaneous masking (both fast and classical methods) were similar and were usually close to, but somewhat above, the values of fe estimated from the TEN(HL) test. Fast PTCs measured in simultaneous masking are recommended for use in clinical practice, as they give a precise estimate of fe and are quick to administer.
Acronyms | ||
BM | = | Basilar membrane |
DR | = | Dead region |
ERBN | = | The average value of equivalent rectangular bandwidth of the auditory filter at moderate sound levels for young listeners with no known hearing loss |
fe | = | Edge frequency of a dead region |
feTEN | = | Edge frequency of a dead region estimated from the TEN(HL) data |
fs | = | Signal frequency |
HF slope | = | High-frequency slope |
IHC | = | Inner hair cell |
LPF | = | Low-pass filtered |
LF | = | Low-frequency |
MDI | = | Modulation detection interference |
MMF | = | Minimum masking frequency |
MMFfast | = | Minimum masking frequency for “fast” PTCs |
MMFFWD | = | Minimum masking frequency for PTCs in forward masking |
MMFSIM | = | Minimum masking frequency for PTCs in simultaneous masking |
PTC | = | Psychophysical tuning curve |
SDT | = | Simple difference tone |
SL | = | Sensation level |
TEN | = | Threshold equalizing noise |
Acronyms | ||
BM | = | Basilar membrane |
DR | = | Dead region |
ERBN | = | The average value of equivalent rectangular bandwidth of the auditory filter at moderate sound levels for young listeners with no known hearing loss |
fe | = | Edge frequency of a dead region |
feTEN | = | Edge frequency of a dead region estimated from the TEN(HL) data |
fs | = | Signal frequency |
HF slope | = | High-frequency slope |
IHC | = | Inner hair cell |
LPF | = | Low-pass filtered |
LF | = | Low-frequency |
MDI | = | Modulation detection interference |
MMF | = | Minimum masking frequency |
MMFfast | = | Minimum masking frequency for “fast” PTCs |
MMFFWD | = | Minimum masking frequency for PTCs in forward masking |
MMFSIM | = | Minimum masking frequency for PTCs in simultaneous masking |
PTC | = | Psychophysical tuning curve |
SDT | = | Simple difference tone |
SL | = | Sensation level |
TEN | = | Threshold equalizing noise |
Sumario
Una región muerta (DR) es una región de la cóclea donde no existen células ciliadas internas y/o neuronas funcionales. Comparamos las frecuencias marginales, fe, de las DR estimadas utilizando cuatro métodos: la prueba de TEN(HL), las curvas psicofísicas de afinamiento (PTC) medidas con enmascaramiento simultáneo (enmascarador de ruido ancho de 320 Hz) usando un método ‘rápido’ (enmascarador de barrido) y un método ‘clásico’; y las PTC medidas con enmascaramiento anterógrado (enmascarador sinusoidal) usando un método clásico. Se evaluaron catorce sujetos con DR de alta frecuencia. Para medir las PTC se escogió una frecuencia de señal que cayera dentro del DR; se consideró que las frecuencias de punta de las PTC indicaban el valor de la fe. Los valores de la fe obtenidos de las PTC con enmascaramiento anterógrado o simultáneo (tanto por método rápido o clásico) fueron similares, y se mantuvieron cerca, aunque un poco por encima, de los valores de la fe estimados de la prueba de TEN(HL). Se recomiendan las PTC rápidas, medidas con enmascaramiento simultáneo para ser utilizadas en la práctica clínica, dado que brindan una estimación precisa de la fe y son rápidas de administrar.