ABSTRACT
Recent evidence suggests the existence of shared neural resources for rhythm processing in language and music. Such overlaps could be the basis of the facilitating effect of regular musical rhythm on spoken word processing previously reported for typical children and adults, as well as adults with Parkinson's disease and children with developmental language disorders. The present study builds upon these previous findings by examining whether non-linguistic rhythmic priming also influences visual word processing, and the extent to which such cross-modal priming effect of rhythm is related to individual differences in musical aptitude and reading skills. An electroencephalogram (EEG) was recorded while participants listened to a rhythmic tone prime, followed by a visual target word with a stress pattern that either matched or mismatched the rhythmic structure of the auditory prime. Participants were also administered standardized assessments of musical aptitude and reading achievement. Event-related potentials (ERPs) elicited by target words with a mismatching stress pattern showed an increased fronto-central negativity. Additionally, the size of the negative effect correlated with individual differences in musical rhythm aptitude and reading comprehension skills. Results support the existence of shared neurocognitive resources for linguistic and musical rhythm processing, and have important implications for the use of rhythm-based activities for reading interventions.
ABSTRACT
Sensitivity to speech rhythm, especially the pattern of stressed and unstressed syllables, is an important aspect of language acquisition and comprehension from infancy through adulthood. In English, a strong correlation exists between speech rhythm and grammatical class. This property is well illustrated by a particular group of noun/verb homographs that are spelled the same but are pronounced with a lexical stress on the first syllable when used as a noun or on the second syllable when used as a verb. The purpose of this study was to further examine the neural markers of speech rhythm and its role in word recognition. To this end, event-related brain potentials were recorded while participants listened to spoken sentences containing a stress homograph either in a noun or a verb position. The rhythmic structure of the stress homographs was manipulated so that they were pronounced with a stress pattern that either matched or mismatched their grammatical class. Results of cluster-based permutation tests on the event-related brain potentials revealed larger negativities over the centrofrontal scalp regions when the stress homographs were mispronounced, in line with previous studies on lexical ambiguity resolution. In addition, differences between rhythmically unexpected nouns and verbs could be seen as early as 200 ms, suggesting that listeners are sensitive to statistical properties of their language rhythm. Together, these results support the hypothesis that information about speech rhythm is rapidly integrated during speech perception and contributes to lexical retrieval.
