Don't speak too fast! Processing of fast rate speech in children with specific language impairment

Does Electrophysiological Maturation Shape Language Acquisition?

Infants master temporal patterns of their native language at a developmental trajectory from slow to fast: Shortly after birth, they recognize the slow acoustic modulations specific to their native language before tuning into faster language-specific patterns between 6 and 12 months of age. We propose here that this trajectory is constrained by neuronal maturation-in particular, the gradual emergence of high-frequency neural oscillations in the infant electroencephalogram. Infants' initial focus on slow prosodic modulations is consistent with the prenatal availability of slow electrophysiological activity (i.e., theta- and delta-band oscillations). Our proposal is consistent with the temporal patterns of infant-directed speech, which initially amplifies slow modulations, approaching the faster modulation range of adult-directed speech only as infants' language has advanced sufficiently. Moreover, our proposal agrees with evidence from premature infants showing maturational age is a stronger predictor of language development than ex utero exposure to speech, indicating that premature infants cannot exploit their earlier availability of speech because of electrophysiological constraints. In sum, we provide a new perspective on language acquisition emphasizing neuronal development as a critical driving force of infants' language development.

Specific Language Impairment and Executive Functions in School-Age Children: A Systematic Review

This systematic review examines the relationship between specific language impairment (SLI) and executive functions (EFs) in school-age children. The study investigates the impact of SLI on EF in comparison to children who develop normally. A total of 2,658 articles from three databases (PubMed, Scopus, and Virtual Health Library) were assessed for inclusion. Ultimately, 22 articles were selected for analysis, which contained information on both SLI and EF. The findings indicate that children diagnosed with SLI exhibit deficits, low performance, and, in some cases, significant deterioration in the development of EF when compared to typically developing children in 62%-91% of cases as early as three to four years of age; the most commonly found alterations were in working memory (including phonological, auditory, and visual/verbal memory), followed by deficits in attention, processing speed, inhibition, planning, cognitive flexibility, and internalized speech. We also discuss the close relationship and importance between language and EF in SLI children.

Regular rhythmic primes improve sentence repetition in children with developmental language disorder

Recently reported links between rhythm and grammar processing have opened new perspectives for using rhythm in clinical interventions for children with developmental language disorder (DLD). Previous research using the rhythmic priming paradigm has shown improved performance on language tasks after regular rhythmic primes compared to control conditions. However, this research has been limited to effects of rhythmic priming on grammaticality judgments. The current study investigated whether regular rhythmic primes could also benefit sentence repetition, a task requiring proficiency in complex syntax-an area of difficultly for children with DLD. Regular rhythmic primes improved sentence repetition performance compared to irregular rhythmic primes in children with DLD and with typical development-an effect that did not occur with a non-linguistic control task. These findings suggest processing overlap for musical rhythm and linguistic syntax, with implications for the use of rhythmic stimulation for treatment of children with DLD in clinical research and practice.

The channel capacity of multilevel linguistic features constrains speech comprehension

Humans are expert at processing speech but how this feat is accomplished remains a major question in cognitive neuroscience. Capitalizing on the concept of channel capacity, we developed a unified measurement framework to investigate the respective influence of seven acoustic and linguistic features on speech comprehension, encompassing acoustic, sub-lexical, lexical and supra-lexical levels of description. We show that comprehension is independently impacted by all these features, but at varying degrees and with a clear dominance of the syllabic rate. Comparing comprehension of French words and sentences further reveals that when supra-lexical contextual information is present, the impact of all other features is dramatically reduced. Finally, we estimated the channel capacity associated with each linguistic feature and compared them with their generic distribution in natural speech. Our data reveal that while acoustic modulation, syllabic and phonemic rates unfold respectively at 5, 5, and 12 Hz in natural speech, they are associated with independent processing bottlenecks whose channel capacity are of 15, 15 and 35 Hz, respectively, as suggested by neurophysiological theories. They moreover point towards supra-lexical contextual information as the feature limiting the flow of natural speech. Overall, this study reveals how multilevel linguistic features constrain speech comprehension.

Using Motor Tempi to Understand Rhythm and Grammatical Skills in Developmental Language Disorder and Typical Language Development

Children with developmental language disorder (DLD) show relative weaknesses on rhythm tasks beyond their characteristic linguistic impairments. The current study compares preferred tempo and the width of an entrainment region for 5- to 7-year-old typically developing (TD) children and children with DLD and considers the associations with rhythm aptitude and expressive grammar skills in the two populations. Preferred tempo was measured with a spontaneous motor tempo task (tapping tempo at a comfortable speed), and the width (range) of an entrainment region was measured by the difference between the upper (slow) and lower (fast) limits of tapping a rhythm normalized by an individual's spontaneous motor tempo. Data from N = 16 children with DLD and N = 114 TD children showed that whereas entrainment-region width did not differ across the two groups, slowest motor tempo, the determinant of the upper (slow) limit of the entrainment region, was at a faster tempo in children with DLD vs. TD. In other words, the DLD group could not pace their slow tapping as slowly as the TD group. Entrainment-region width was positively associated with rhythm aptitude and receptive grammar even after taking into account potential confounding factors, whereas expressive grammar did not show an association with any of the tapping measures. Preferred tempo was not associated with any study variables after including covariates in the analyses. These results motivate future neuroscientific studies of low-frequency neural oscillatory mechanisms as the potential neural correlates of entrainment-region width and their associations with musical rhythm and spoken language processing in children with typical and atypical language development.

A Comparative Study Across Methods to Identify Adolescents with Syntactic Specific Language Impairment

Background

Specific language impairment (SLI) is described as a heterogeneous deficit that causes difficulties in various aspects of language. We performed a comparative study of two methods of language assessment with the primary objective of determining the most effective approach for identifying adolescents with syntactic SLI and typical development (TD) in use.

Methods

A software-assisted method using E-Prime 2.0 was used to create an experiment. The participants were Malay adolescents aged 13 years old-15 years old. The conventional method was compared with the software-assisted method to assess the participants' comprehension and production performance. Data on reaction time (RT), scoring and no response (NR) were obtained from the adolescents.

Results

Based on the two methods, the findings on the selection of participants for the SLI and TD groups was different. The two methods produced similar results in terms of the selection of TD group and most participants in the syntactic SLI group except for two participants who failed in the conventional method but passed the test in the software-assisted method.

Conclusion

The descriptive evaluation of the findings suggested selecting software-assisted method as the alternative source because the provided information was detailed and this information enabled the researcher to identify the SLI group.

Neural oscillations track natural but not artificial fast speech: Novel insights from speech-brain coupling using MEG

Neural oscillations contribute to speech parsing via cortical tracking of hierarchical linguistic structures, including syllable rate. While the properties of neural entrainment have been largely probed with speech stimuli at either normal or artificially accelerated rates, the important case of natural fast speech has been largely overlooked. Using magnetoencephalography, we found that listening to naturally-produced speech was associated with cortico-acoustic coupling, both at normal (∼6 syllables/s) and fast (∼9 syllables/s) rates, with a corresponding shift in peak entrainment frequency. Interestingly, time-compressed sentences did not yield such coupling, despite being generated at the same rate as the natural fast sentences. Additionally, neural activity in right motor cortex exhibited stronger tuning to natural fast rather than to artificially accelerated speech, and showed evidence for stronger phase-coupling with left temporo-parietal and motor areas. These findings are highly relevant for our understanding of the role played by auditory and motor cortex oscillations in the perception of naturally produced speech.

Processing rhythm in speech and music: Shared mechanisms and implications for developmental speech and language disorders

OBJECTIVE

Music and speech are complex signals containing regularities in how they unfold in time. Similarities between music and speech/language in terms of their auditory features, rhythmic structure, and hierarchical structure have led to a large body of literature suggesting connections between the two domains. However, the precise underlying mechanisms behind this connection remain to be elucidated.

METHOD

In this theoretical review article, we synthesize previous research and present a framework of potentially shared neural mechanisms for music and speech rhythm processing. We outline structural similarities of rhythmic signals in music and speech, synthesize prominent music and speech rhythm theories, discuss impaired timing in developmental speech and language disorders, and discuss music rhythm training as an additional, potentially effective therapeutic tool to enhance speech/language processing in these disorders.

RESULTS

We propose the processing rhythm in speech and music (PRISM) framework, which outlines three underlying mechanisms that appear to be shared across music and speech/language processing: Precise auditory processing, synchronization/entrainment of neural oscillations to external stimuli, and sensorimotor coupling. The goal of this framework is to inform directions for future research that integrate cognitive and biological evidence for relationships between rhythm processing in music and speech.

CONCLUSION

The current framework can be used as a basis to investigate potential links between observed timing deficits in developmental disorders, impairments in the proposed mechanisms, and pathology-specific deficits which can be targeted in treatment and training supporting speech therapy outcomes. On these grounds, we propose future research directions and discuss implications of our framework. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Comparison of the Effects of Two Cochlear Implant Fine Structure Coding Strategies on Speech Perception

Purpose This study aims to investigate the effect of upgrading from the fine structure processing (FSP) coding strategy to the novel fine structure strategy "FS4" in adults in adults with cochlear implants manufactured by MED-EL GmbH (Innsbruck, Austria). Method A crossover, double-blinded study was conducted for 12 weeks. Twelve adult participants were randomly assigned to two groups. During the first 6-week test interval, one group continued to use their everyday FSP strategy, whereas the other group was upgraded to the FS4 strategy. In the second 6-week interval, the two groups switched coding strategies. Speech perception was measured at the end of each test interval with the Oldenburg Sentence Test and the Göttingen Sentence Test. Participants completed the Speech, Spatial and Qualities of Hearing Scale at the end of each test interval and a simple preference test at the end of the study. Results There was no significant difference in speech perception test results obtained with the Oldenburg Sentence Test and the Göttingen Sentence Test, neither in quiet nor in noise. Participants' Speech, Spatial and Qualities of Hearing Scale self-evaluation and preference test results showed that the two coding strategies had similar effects on their hearing perception. No clear preference for either of the strategies was found. Conclusions Speech perception test results and the participants' level of satisfaction were similar for the two FS coding strategies. Despite differences in the presentation of temporal fine structure between FSP and FS4, a clear benefit of the newer FS4 strategy could not be shown.

Does Time Compression Decrease Intelligibility for Female Talkers More Than for Male Talkers?

Purpose This preliminary investigation compared effects of time compression on intelligibility for male versus female talkers. We hypothesized that time compression would have a greater effect for female talkers. Method Sentence materials from four talkers (two males) were time compressed, and original-speed and time-compressed speech materials were presented in a background of 12-talker babble to young adult listeners with normal hearing. Each talker/processing condition was heard by eight listeners (total N = 64). Generalized linear mixed-effects models were used to determine the effects of and interaction between processing condition and talker sex on keyword intelligibility. Additional post hoc analyses examined whether processing condition effects were related to talker vowel space and word frequency. Results For original-speed sentences, female and male talkers were essentially equally intelligible. Time compression reduced intelligibility for all talkers, but the effect was significantly greater for the female talkers. Supplementary analyses revealed that the effect of time compression depended on both talker vowel space and word frequency: The detrimental effect decreased significantly as word frequency and vowel space increased. Word frequency effects were also greater overall for talkers with larger vowel spaces. Conclusions While the small talker sample limits conclusions about the effects of talker sex, the secondary analyses suggest that intelligibility of talkers with larger vowel spaces is less susceptible to the negative effect of time compression, especially for high-frequency words.

Pushing the Envelope: Developments in Neural Entrainment to Speech and the Biological Underpinnings of Prosody Perception

Prosodic cues in speech are indispensable for comprehending a speaker’s message, recognizing emphasis and emotion, parsing segmental units, and disambiguating syntactic structures. While it is commonly accepted that prosody provides a fundamental service to higher-level features of speech, the neural underpinnings of prosody processing are not clearly defined in the cognitive neuroscience literature. Many recent electrophysiological studies have examined speech comprehension by measuring neural entrainment to the speech amplitude envelope, using a variety of methods including phase-locking algorithms and stimulus reconstruction. Here we review recent evidence for neural tracking of the speech envelope and demonstrate the importance of prosodic contributions to the neural tracking of speech. Prosodic cues may offer a foundation for supporting neural synchronization to the speech envelope, which scaffolds linguistic processing. We argue that prosody has an inherent role in speech perception, and future research should fill the gap in our knowledge of how prosody contributes to speech envelope entrainment.