Effects of age and hearing loss on the intelligibility of interrupted speech

Abstract

How age and hearing loss affect the perception of interrupted speech may vary based on both the physical properties of preserved or obliterated speech fragments and individual listener characteristics. To investigate perceptual processes and interruption parameters influencing intelligibility across interruption rates, participants of different age and hearing status heard sentences interrupted by silence at either a single primary rate (0.5-8 Hz; 25%, 50%, 75% duty cycle) or at an additional concurrent secondary rate (24 Hz; 50% duty cycle). Although age and hearing loss significantly affected intelligibility, the ability to integrate sub-phonemic speech fragments produced by the fast secondary rate was similar in all listener groups. Age and hearing loss interacted with rate with smallest group differences observed at the lowest and highest interruption rates of 0.5 and 24 Hz. Furthermore, intelligibility of dual-rate gated sentences was higher than single-rate gated sentences with the same proportion of retained speech. Correlations of intelligibility of interrupted speech to pure-tone thresholds, age, or measures of working memory and auditory spectro-temporal pattern discrimination were generally low-to-moderate and mostly nonsignificant. These findings demonstrate rate-dependent effects of age and hearing loss on the perception of interrupted speech, suggesting complex interactions of perceptual processes across different time scales.

The intelligibility of interrupted and temporally altered speech: Effects of context, age, and hearing loss

“…Furthermore, the rate-dependent effect of concatenation on the intelligibility of gated speech reported by Shafiro et al (2011b), with a local minima at 2 Hz, is consistent with the previous findings of a U-shaped performance function across interruption rates (Miller and Licklider, 1950;Huggins, 1975;Nelson and Jin, 2004;Jin and Nelson, 2010;Shafiro et al, 2011a;Shafiro 2011b;Saija et al, 2014;Shafiro et al, 2015). This characteristic function shape has been attributed to differences in the perceptual processes that support intelligibility on the low-and high-frequency sides of the rate-intelligibility function (Huggins,1975;Ghitza and Greenberg, 2009;Ghitza, 2011;Shafiro et al, 2015).…”

“…Subsequent to compression, the sentences were interrupted by either gating with silence or with noise at six interruption rates: 0.625, 1.25, 2.5, 5, 10, and 20 Hz. As in other research with interrupted speech (Kidd and Humes, 2010;Molis et al, 2015;Shafiro et al, 2015;Fogerty et al, 2015), young adults outperformed older listeners overall. Sentences interrupted with noise were considerably more intelligible than those interrupted with silence.…”

“…Past research has indicated that intelligibility of interrupted speech is strongly affected by the proportion of audible glimpses, i.e., the proportion of the original speech signal that can be detected (Cooke, 2006;Buss et al, 2009;Wang and Humes, 2010;Kidd and Humes, 2010). However, other studies have also revealed a highly nonlinear interaction pattern between the proportion of the original speech retained and intelligibility (Gustafsson and Arlinger, 1994;Wang and Humes, 2010;Shafiro et al, 2011a;Shafiro et al, 2015). In that context, combining periodic interruptions with temporal alterations of speech has been a useful approach for identifying the temporal constraints on the perceptual integration of speech fragments of different duration.…”

“…This characteristic function shape has been attributed to differences in the perceptual processes that support intelligibility on the low-and high-frequency sides of the rate-intelligibility function (Huggins,1975;Ghitza and Greenberg, 2009;Ghitza, 2011;Shafiro et al, 2015). On the low side, remaining speech fragments are, on average, long enough to support the percept of full words, while intervals between the fragments may be too long to effectively "bridge" the gaps.…”

“…The rate of interruption and the duty cycle (i.e., the percentage of speech-on time during each interruption cycle) can be gradually varied to control access to the information in the speech signal, thus revealing its perceptually salient aspects. The general finding has been that for many interruption rates, high intelligibility can be maintained with as little as 25%-50% of the original signal remaining (Miller and Licklider, 1950;Nelson and Jin, 2004;Shafiro et al, 2011a;Saija et al, 2014;Shafiro et al, 2015). Some investigators have also adopted this experimental approach to study contributions of temporal constraints on the perceptual processing of speech (Garvey, 1953;Huggins, 1964;Heiman et al, 1986;Shafiro et al, 2011b;Saija et al, 2014;Ghitza, 2014).…”