Variability of the slope of the loudness function in normal and impaired hearing

Abstract

The variability of the slope of the loudness function was determined within and across groups of people with normal and impaired hearing. Slope values were obtained from magnitude estimation and production of loudness and from cross‐modality matching and magnitude estimation of apparent length. Loudness judgments were made for 1‐s tone bursts at a frequency in the 500‐ to 2000‐Hz range by more than 30 people from the general population with normal hearing in the midfrequency region. Twenty people also judged loudness at three frequencies in the same ear, two in the region of impaired heating and one in the region of normal hearing. Over a wide stimulus range, the relation between loudness and sound pressure for normal hearing was a power function with a slope in log‐log coordinates close to 0.60. Both the means and standard deviations of the slopes increased with the degree of hearing loss. These results are compared to those reported in a current paper [R. P. Hellman and C. H. Meiselman, J. Acoust. Soc. Am. 88 (in press)] for five different groups, one with normal hearing and four with noise‐induced cochlear impairments. [Work supported by the Rehabilitation Research and Development Service of the VA.]