Age effects on perceptual organization of speech: Contributions of glimpsing, phonemic restoration, and speech segregation

Abstract

In realistic listening environments, speech perception requires grouping together audible fragments of speech, filling in missing information, and segregating the glimpsed target from the background. The purpose of this study was to determine the extent to which age-related difficulties with these tasks can be explained by declines in glimpsing, phonemic restoration, and/or speech segregation. Younger and older adults with normal hearing listened to sentences interrupted with silence or envelope-modulated noise, presented either in quiet or with a competing talker. Older adults were poorer than younger adults at recognizing keywords based on short glimpses but benefited more when envelope-modulated noise filled silent intervals. Recognition declined with a competing talker but this effect did not interact with age. Results of cognitive tasks indicated that faster processing speed and better visual-linguistic closure were predictive of better speech understanding. Taken together, these results suggest that age-related declines in speech recognition may be partially explained by difficulty grouping short glimpses of speech into a coherent message.

Speech aging: Production and perception

“…While speech masking has been shown to increase the difficulty for both younger and older listeners, perception in masking tasks is more difficult for older listeners, who make more mistakes regardless of possible hearing loss (Helfer et al, 2010; Helfer & Freyman, 2014). In two studies using different types of interruptions while listeners perceived speech, researchers found that both younger and older listeners performance was inhibited but older listeners showed greater effects of the interruptions (Bologna et al, 2018, 2019). Thus, overall across a variety of masking types, older adults have more difficulty perceiving speech in noise than younger adults.…”

Contributions of Voice Expectations to Talker Selection in Younger and Older Adults With Normal Hearing

“…Data were scored at the keyword level (rather than the sentence level) so that the effect of keyword position could be included in the model. This factor has been shown in previous studies to predict keyword recognition and provides some insight into the time course of speech segregation and selection (e.g., Ben-David et al, 2012;Bologna et al, 2018). Initial attempts to model the data included a sentence identifier as an additional random effect to improve model fit.…”

“…Additional data from a battery of cognitive measures were available for these participants from two other studies completed at the same time (Bologna et al, 2018(Bologna et al, , 2019. The cognitive measures were included in statistical models described later to assess the contributions of several cognitive abilities to speech recognition and object selection.…”

“…Numerous studies have demonstrated that older adults are poorer than younger adults at understanding speech in multitalker environments, even after accounting for differences in hearing sensitivity (Bologna et al, 2018;Helfer & Freyman, 2008;Rajan & Cainer, 2008). In many cases, these results have been interpreted as agerelated declines in perceptual segregation of speech (e.g., Ben-David et al, 2012;Ezzatian et al, 2015;Lee & Humes, 2012).…”

Relationship between Speech Perception in Noise and Phonemic Restoration of Speech in Noise in Individuals with Normal Hearing

“…While it is well-known that speech perception in noise is affected in individuals with sensorineural hearing loss and in those rehabilitated with cochlear implants, phonemic restoration has also been reported to be reduced in these two groups [ 6 , 11 , 14 ] suggesting that speech in noise performance and phonemic restoration maybe positively correlated. On the other hand, speech in noise performance is affected in older subjects [ 15 ], but phonemic restoration magnitude seems to be larger than relative to younger subjects [ 7 , 16 , 17 ]. It may well be that the two processes may not be correlated at all and may represent two independent processes.…”