Auditory thresholds using varying attenuation rate (attenuation step) and suprathreshold starting intensity

Bekesy fixed-frequency thresholds for pulsed and continuous tones were compared for different starting intensities and attenuation rates (attenuation steps) in subjects with normal hearing. Starting intensities were 38, 58, 78, and 98 dB SPL. Attenuation rates were 1, 2, 4, and 8 dB/s with attenuation steps in 0.25, 0.5, 1.0, and 2.0 dB/s, respectively. For pulsed tones, the threshold was not significantly affected by varying starting intensities or attenuation rates (attenuation steps). Reducing the attenuation rate (attenuation step) produced an elevation of continuous tone thresholds for a given suprathreshold starting intensity. Increase in the suprathreshold starting intensity produced an elevation of continuous tone thresholds for a given attenuation rate (attenuation step). The slower the attenuation rate (the slower the attenuation step) and the higher the suprathreshold starting intensity, the higher the threshold. This is considered a manifestation of normal adaptation. Present findings were compared and discussed with our previous studies for the threshold differences measured by different attenuation rates with a fixed attenuation step in 0.2 dB starting at the same suprathreshold intensities.