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.

Exploring individual differences in musical rhythm and grammar skills in school-aged children with typically developing language.

A growing number of studies have shown a connection between rhythmic processing and language skill. It has been proposed that domain-general rhythm abilities might help children to tap into the rhythm of speech (prosody), cueing them to prosodic markers of grammatical (syntactic) information during language acquisition, thus underlying the observed correlations between rhythm and language. Working memory processes common to task demands for musical rhythm discrimination and spoken language paradigms are another possible source of individual variance observed in musical rhythm and language abilities. To investigate the nature of the relationship between musical rhythm and expressive grammar skills, we adopted an individual differences approach in N = 132 elementary school-aged children ages 5-7, with typical language development, and investigated prosodic perception and working memory skills as possible mediators. Aligning with the literature, musical rhythm was correlated with expressive grammar performance (r = 0.41, p < 0.001). Moreover, musical rhythm predicted mastery of complex syntax items (r = 0.26, p = 0.003), suggesting a privileged role of hierarchical processing shared between musical rhythm processing and children's acquisition of complex syntactic structures. These relationships between rhythm and grammatical skills were not mediated by prosodic perception, working memory, or non-verbal IQ; instead, we uncovered a robust direct effect of musical rhythm perception on grammatical task performance. Future work should focus on possible biological endophenotypes and genetic influences underlying this relationship.

The Relationship Between Pitch Discrimination and Fundamental Frequency Variation: Effects of Singing Status and Vocal Hyperfunction.

PURPOSE: The purpose of this study was to investigate the relationship between pitch discrimination and fundamental frequency (fo) variation in running speech, with consideration of factors such as singing status and vocal hyperfunction (VH). METHOD: Female speakers (18-69 years) with typical voices (26 non-singers; 27 singers) and speakers with VH (22 non-singers; 30 singers) completed a pitch discrimination task and read the Rainbow Passage. The pitch discrimination task was a two-alternative forced choice procedure, in which participants determined whether tokens were the same or different. Tokens were a prerecorded sustained /ɑ/ of the participant's own voice and a pitch-shifted version of their sustained /ɑ/, such that the difference in fo was adaptively modified. Pitch discrimination and Rainbow Passage fo variation were calculated for each participant and compared via Pearson's correlations for each group. RESULTS: A significant strong correlation was found between pitch discrimination and fo variation for non-singers with typical voices. No significant correlations were found for the other three groups, with notable restrictions in the ranges of discrimination for both singer-groups and in the range of fo variation values for non-singers with VH. CONCLUSIONS: Speakers with worse pitch discrimination may increase their fo variation to produce self-salient intonational changes, which is in contrast to previous findings from articulatory investigations. The erosion of this relationship in groups with singing training and/or with VH may be explained by the known influence of musical training on pitch discrimination or the biomechanical changes associated with VH restricting speakers' abilities to change their fo.