Use of semantic context and F0 contours by older listeners during Mandarin speech recognition in quiet and single-talker interference conditions

Aging-Related Decline in Phonated and Whispered Speech Perception Not Compensated For by Increased Duration and Intensity: Evidence From Mandarin-Speaking Adult Listeners

PURPOSE

This study aimed to examine how aging and modifications of critical acoustic parameters may affect the perception of whispered speech as a degraded signal.

METHOD

Forty Mandarin-speaking adults were included in the study. Part 1 of the study compared the perception of Mandarin lexical tones, vowels, and syllables in older and younger adults in whispered versus phonated speech conditions. Parts 2 and 3 further examined how modification of duration and intensity cues contributed to the perceptual outcomes.

RESULTS

Perception of whispered tones was compromised in older and younger adults. Older adults identified lexical tones less accurately than their younger counterparts, particularly for phonated T2 and T3 and whispered T3. Aging also negatively affected the vowel identification of /i, u/ in the whispered condition. Syllable-level accuracy was largely dependent on the accuracy of lexical tones and vowels. Furthermore, reduced duration led to the decreased accuracy of phonated T3 and whispered T2 and T3 but increased accuracy of phonated T4. Reduced intensity lowered the recognition accuracy for phonated vowels /i, ɤ, o, y/ in older adults and /i, u/ in younger adults, and it also lowered the accuracy of whispered vowels /a, ɤ/ in older adults. Contrary to our expectation, increased duration and intensity did not improve older adults' speech perception in either phonated or whispered conditions.

CONCLUSIONS

The results suggest that aging adversely affected speech perception in both phonated and whispered conditions with more challenges in identifying whispered speech for older adults. While older adults' diminished performance may be potentially due to problems with processing the degraded temporal and spectral information of the target speech sounds, it cannot be simply compensated for by increasing the duration and intensity of the target sounds beyond the audible level.

The effect of aging on context use and reliance on context in speech: A behavioral experiment with Repeat–Recall Test

Purpose

To elucidate how aging would affect the extent of semantic context use and the reliance on semantic context measured with the Repeat–Recall Test (RRT).

Methods

A younger adult group (YA) aged between 18 and 25 and an older adult group (OA) aged between 50 and 65 were recruited. Participants from both the groups performed RRT: sentence repeat and delayed recall tasks, and subjective listening effort and noise tolerable time, under two noise types and seven signal-to-noise ratios (SNR). Performance–Intensity curves were fitted. The performance in SRT50 and SRT75 was predicted.

Results

For the repeat task, the OA group used more semantic context and relied more on semantic context than the YA group. For the recall task, OA used less semantic context but relied more on context than the YA group. Age did not affect the subjective listening effort but significantly affected noise tolerable time. Participants in both age groups could use more context in SRT75 than SRT50 on four tasks of RRT. Under the same SRT, however, the YA group could use more context in repeat and recall tasks than the OA group.

Conclusion

Age affected the use and reliance of semantic context. Even though the OA group used more context in speech recognition, they failed in speech information maintenance (recall) even with the help of semantic context. The OA group relied more on context while performing repeat and recall tasks. The amount of context used was also influenced by SRT.

How Visual Word Decoding and Context-Driven Auditory Semantic Integration Contribute to Reading Comprehension: A Test of Additive vs. Multiplicative Models

Theories of reading comprehension emphasize decoding and listening comprehension as two essential components. The current study aimed to investigate how Chinese character decoding and context-driven auditory semantic integration contribute to reading comprehension in Chinese middle school students. Seventy-five middle school students were tested. Context-driven auditory semantic integration was assessed with speech-in-noise tests in which the fundamental frequency (F₀) contours of spoken sentences were either kept natural or acoustically flattened, with the latter requiring a higher degree of contextual information. Statistical modeling with hierarchical regression was conducted to examine the contributions of Chinese character decoding and context-driven auditory semantic integration to reading comprehension. Performance in Chinese character decoding and auditory semantic integration scores with the flattened (but not natural) F₀ sentences significantly predicted reading comprehension. Furthermore, the contributions of these two factors to reading comprehension were better fitted with an additive model instead of a multiplicative model. These findings indicate that reading comprehension in middle schoolers is associated with not only character decoding but also the listening ability to make better use of the sentential context for semantic integration in a severely degraded speech-in-noise condition. The results add to our better understanding of the multi-faceted reading comprehension in children. Future research could further address the age-dependent development and maturation of reading skills by examining and controlling other important cognitive variables, and apply neuroimaging techniques such as functional magmatic resonance imaging and electrophysiology to reveal the neural substrates and neural oscillatory patterns for the contribution of auditory semantic integration and the observed additive model to reading comprehension.

Sentence Context Differentially Modulates Contributions of Fundamental Frequency Contours to Word Recognition in Chinese-Speaking Children With and Without Dyslexia

Previous work has shown that children with dyslexia are impaired in speech recognition in adverse listening conditions. Our study further examined how semantic context and fundamental frequency (F₀) contours contribute to word recognition against interfering speech in dyslexic and non-dyslexic children. Thirty-two children with dyslexia and 35 chronological-age-matched control children were tested on the recognition of words in normal sentences versus wordlist sentences with natural versus flat F₀ contours against single-talker interference. The dyslexic children had overall poorer recognition performance than non-dyslexic children. Furthermore, semantic context differentially modulated the effect of F₀ contours on the recognition performances of the two groups. Specifically, compared with flat F₀ contours, natural F₀ contours increased the recognition accuracy of dyslexic children less than non-dyslexic children in the wordlist condition. By contrast, natural F₀ contours increased the recognition accuracy of both groups to a similar extent in the sentence condition. These results indicate that access to semantic context improves the effect of natural F₀ contours on word recognition in adverse listening conditions by dyslexic children who are more impaired in the use of natural F₀ contours during isolated and unrelated word recognition. Our findings have practical implications for communication with dyslexic children when listening conditions are unfavorable.

The effect of F0 contour on the intelligibility of Mandarin Chinese for hearing-impaired listeners

Dynamic F0 contour plays an important role in recognizing speech. The present work examined the effect of F0 contour on speech intelligibility for hearing-impaired listeners for Mandarin Chinese in quiet, in steady noise, and in two-talker competing speech. The intelligibility of two types of natural speech was measured: single-Tone speech with relatively flat F0 contours and multi-Tone speech with time-varying F0 contours. The speech rate and mean F0 of speech materials were carefully controlled to avoid effects other than F0 contour on the speech intelligibility. Results showed that intelligibility was significantly higher for speech with a flat F0 contour than that with a dynamic F0 contour at a low signal-to-masker ratio in both speech-spectrum noise and two-talker masker.

Mandarin-Speaking, Kindergarten-Aged Children With Cochlear Implants Benefit From Natural F 0 Patterns in the Use of Semantic Context During Speech Recognition

PURPOSE

The purpose of this study was to investigate the extent to which semantic context and F0 contours affect speech recognition by Mandarin-speaking, kindergarten-aged children with cochlear implants (CIs).

METHOD

The experimental design manipulated two factors, that is, semantic context, by comparing the intelligibility of normal sentence versus word list, and F0 contours, by comparing the intelligibility of utterances with natural versus flat F0 patterns. Twenty-two children with CIs completed a speech recognition test.

RESULTS

Children with CIs could use both semantic context and F0 contours to assist speech recognition. Furthermore, natural F0 patterns provided extra benefit when semantic context was present than when it was absent.

CONCLUSION

Dynamic F0 contours play an important role in speech recognition by Mandarin-speaking children with CIs despite the well-known limitation of CI devices in extracting F0 information.

The underlying mechanism of deficits of speech comprehension and hallucinations in Chinese patients with schizophrenia

Sentence context and fundamental frequency (F0) contours are important factors to speech perception and comprehension. In Chinese-Mandarin, lexical tones can be distinguished by the F0 contours. Previous studies found healthy people could use the cue of context to recover the phonological representations of lexical tones from the altered tonal patterns to comprehend the sentences in quiet condition, but can not in noise environment. Lots of research showed that patients with schizophrenia have deficits of speech perception and comprehension. However, it is unclear how context and F0 contours influence speech perception and comprehension in patients with schizophrenia. This study detected the contribution of context and lexical tone to sentence comprehension in four types of sentences by manipulating the context and F0 contours in 32 patients with schizophrenia and 33 healthy controls. The results showed that (1) in patients with schizophrenia, the interaction between context and F0 contour was not significant, which was significant in healthy controls; (2) the scores of sentences with two types of sentences with flattened F0 contours were negatively correlated with hallucination trait scores; (3) the patients with schizophrenia showed significantly lower scores on the intelligibility of sentences in all conditions, which were negatively correlated with PANSS-P. The patients with schizophrenia couldn't use the cue of context to recover the phonological representations of lexical tones from the altered tonal patterns when they comprehend the sentences, inner noise may be the underlying mechanism for the deficits of speech perception and comprehension.

Mandarin-Speaking Children's Speech Recognition: Developmental Changes in the Influences of Semantic Context and F0 Contours

The goal of this developmental speech perception study was to assess whether and how age group modulated the influences of high-level semantic context and low-level fundamental frequency (F₀) contours on the recognition of Mandarin speech by elementary and middle-school-aged children in quiet and interference backgrounds. The results revealed different patterns for semantic and F₀ information. One the one hand, age group modulated significantly the use of F₀ contours, indicating that elementary school children relied more on natural F₀ contours than middle school children during Mandarin speech recognition. On the other hand, there was no significant modulation effect of age group on semantic context, indicating that children of both age groups used semantic context to assist speech recognition to a similar extent. Furthermore, the significant modulation effect of age group on the interaction between F₀ contours and semantic context revealed that younger children could not make better use of semantic context in recognizing speech with flat F₀ contours compared with natural F₀ contours, while older children could benefit from semantic context even when natural F₀ contours were altered, thus confirming the important role of F₀ contours in Mandarin speech recognition by elementary school children. The developmental changes in the effects of high-level semantic and low-level F₀ information on speech recognition might reflect the differences in auditory and cognitive resources associated with processing of the two types of information in speech perception.