Cross-Modality Matching: A Tool for Measuring Loudness in Sensorineural Impairment

OBJECTIVE:The main goal of this study was to establish the viability of cross-modality matching (CMM) for the measurement of individual loudness functions in sensorineural-impaired hearing. To achieve this goal, CMM was tested rigorously to assess four measurement requirements1) internal consistency; 2) small relative variance across listeners; 3) test-retest reliability; and 4) data validity. DESIGN:The measurements involved two sensory continuaperceived length and loudness. Sensation-magnitude functions were generated for all listeners from absolute magnitude estimation (AME) of perceived length, from CMM between loudness and perceived length, and from AME and absolute magnitude production (AMP) of loudness. A total of 211 listeners, 83 with normal hearing at the stimulus frequency and 128 with a diagnosis of cochlear impairment of long duration, performed all four magnitude-scaling tasks. Supplementary loudness matches also were obtained. RESULTS:Based on the analysis of data, the following results were obtained. First, in accord with loudness measures in normal hearing, loudness measures in cochlear-impaired hearing showed that individuals with bilateral impairments can produce internally consistent loudness data. Second, over the stimulus range where cochlear impairment steepens the loudness function, in a log-log plot loudness slopes derived from CMM, like those obtained from AME and AMP of loudness, were larger in cochlear-impaired hearing than in normal hearing. However, the results of CMM were typically less variable than those obtained from AME and AMP of loudness, permitting a clear-cut distinction between loudness growth rates (slopes) in normal and cochlear-impaired hearing. Third, the results showed that within a cochlear-impaired population, much of the intersubject variability of the slope of the loudness function can be ascribed to the heterogeneity of individual thresholds. Consistent with loudness matching, the size of the slopes increased with the degree of hearing loss. The dependence of the size of the slopes on the degree of hearing loss was observed for hearing losses as large as 75 dB. Fourth, test-retest reliability data for 36 listeners showed that CMM can yield reliable and stable loudness-growth measures in cochlear-impaired hearing over the long term. Finally, equal-sensation matches obtained directly from loudness matching closely agreed with those obtained indirectly from magnitude scaling, indicating that CMM is a valid met