Equal sensation functions in bilateral sensorineural-impaired hearing

Equal sensation functions were generated for individuals and groups with hearing losses ranging from 39 to 73 dB at the stimulus frequency. The functions were obtained directly from conventional loudness matching, and indirectly from magnitude estimation, magnitude production, and cross-modality matching. The results of the direct and indirect loudness-level determinations lie within a relatively narrow band. On the average, the intrasubject variability across procedures ranges from 4 to 6 dB. The corresponding intersubject variability has a mean value of 4.6 dB. Moreover, cross-modality matches obtained for 36 listeners exhibit temporal stability for intersession intervals as long as 5 years. Loudness functions constructed from the data are better described by Zwislocki’s [HandbookofMathematicalPsychology, 3–97 (1965)] proposed loudness equation than by either of the more widely applied power-law modifications. [Work supported by the Rehab R&D Service of the VA and by NIH.]