| 摘要 |
Apparatus for conditioning the hearing of a patient is disclosed. A signal level detector establishes whether an incoming audio signal is above or below a threshold level to gate the audio signal to one or other of two parallel channels. The first channel has a frequency response curve in which high frequencies are suppressed and thus is the channel used when the audio signal is below the threshold. The other channel has a frequency response curve in which low frequencies are suppressed and this is the channel used when the audio signal exceeds the threshold. Two parallel output stages are provided, one including an electromechanical vibrator which is placed on the patient's skull and the other including earphones worn by the patient. A time delay module is also provided so that when switching from the one channel to the other channel occurs, the vibrator is switched to the other channel a predetermined time before the earphones which causes the conduction of vibrations through the patient's skull to precede the conduction of sound waves in air. This has the effect of preparing the patient for receipt of the air sound waves and can improve his speech.
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