Effects of Varying Attenuation Rate and Starting Intensity on Békésy Threshold

Bekesy fixed‐frequency initial threshold and threshold of equilibrium for pulsed and continuous tones were compared for different starting intensities in normal and pathological ears. For pulsed tones, the initial threshold as measured by the bottom of the first spike was not significantly affected by varying attenuation rates or starting intensities in normal ears and in pathological ears without abnormal adaptation. For abnormally adapting ears, higher thresholds were usually produced by suprathreshold than by infrathreshold starting intensity. Halving the attenuation rate produced about 1.5‐dB elevation of continuous‐tone thresholds for a given suprathreshold starting intensity in normals and cochlear lesions. Each 20‐dB increase in the suprathreshold starting intensity produced about 1.5‐dB elevation of continuous‐tone thresholds in normal ears. In cochlear lesions, the elevation amounted to 5 dB. Threshold at equilibrium was unchanged in all ears regardless of starting intensity level.