Temporal integration of forward masking in listeners having sensorineural hearing loss

Abstract

Findings are described from three experiments that were designed to contrast estimates of auditory time and frequency analysis in highly practiced, young adult subjects having sensorineural hearing loss of cochlear origin with subjects having normal hearing. In one experiment, pure-tone detection threshold was measured for two durations of tones. For the hearing-impaired subjects, smaller differences were found between thresholds for the two durations of tones than were found for the normally hearing subjects at test frequencies where the sensitivity loss was greatest. In a subsequent forward masking experiment, masked thresholds were obtained at 3 kHz as a function of masker level at several masker durations. The results indicated that, for the range of values tested, masked probe thresholds changed less as a function of masker duration for the hearing-impaired subjects than for normally hearing subjects. However, forward masking grew as a function of masker level more steeply for the hearing-impaired listeners than for the normally hearing listeners. We believe that this result indicates abnormal temporal processing of sequential sounds. In a third experiment, psychophysical tuning curves were measured in a forward masking procedure for two maskers that differed in duration by approximately an order of magnitude. Again, the hearing-impaired subjects demonstrated less change in forward masking as a function of masker duration than normally hearing subjects. Further, the sharpness of the tuning curves from the hearing-impaired listeners was markedly reduced as compared to normal. It is believed that the results reflect a disruption of the normal temporal and spectral representation of sounds in the hearing-impaired subjects.

Evaluating the effects of olivocochlear feedback on psychophysical measures of frequency selectivity

“…From these findings they concluded that the MOC has only a weak influence on the temporal aspects of masking. As stated earlier, similar small effects of masker duration are present in the literature involving frequency selectivity (e.g., Kidd et al, 1984;Bacon and Jesteadt, 1987). The present study and previous studies using precursors have shown that the MOC may play a large role in temporal masking (Strickland, 2001;Krull and Strickland, 2008;Jennings et al, 2009;Roverud and Strickland, 2010).…”

“…In forward masking, where the masker does not suppress the signal, studies comparing estimates of frequency selectivity for short and long maskers have produced similarly mixed results, with one study reporting slightly broader tuning with masker duration (Kidd et al, 1984) and another reporting sharper tuning (Bacon and Jesteadt, 1987). Based on the assumption that the MOC reflex plays a role in the dynamics of frequency selectivity, it may be difficult to observe a large change in tuning between short and long maskers.…”

The influence of hearing-aid compression on forward-masked thresholds for adults with hearing loss

“…The findings that the prescriptive procedure and compression speed affect forward masking are consistent with previous research on forward masking. When differences in audibility are minimized between the two groups (NH and SNHL) disparities in forward masking are reduced (Kidd et al, 1985;Schairer et al, 2008). Desloge et al (2011) demonstrated that mimicking the loss of audibility and cochlear compression in the impaired ear using listeners with NH reduced differences in forward masking relative to listeners with SNHL.…”

Conductive Hearing Loss Disrupts Synaptic and Spike Adaptation in Developing Auditory Cortex

“…2, 3), it is plausible that percepts such as forward masking could also be disrupted. For example, subjects with hearing loss exhibit greater forward masking (Kidd et al, 1984;Gagne, 1988), making it harder to detect soft signals in a noisy environment.…”