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Music, rhythm, rise time perception and developmental dyslexia: Perception of musical meter predicts reading and phonology

Conclusions
The accurate perception of metrical structure may be critical for phonological development and consequently for the development of literacy. Difficulties in metrical processing are associated with basic auditory rise time processing difficulties, suggesting a primary sensory impairment in developmental dyslexia in tracking the lower-frequency modulations in the speech envelope.

from Cortex

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Music, rhythm, rise time perception and developmental dyslexia: Perception of musical meter predicts reading and phonology

Rhythm organises musical events into patterns and forms, and rhythm perception in music is usually studied by using metrical tasks. Metrical structure also plays an organisational function in the phonology of language, via speech prosody, and there is evidence for rhythmic perceptual difficulties in developmental dyslexia. Here we investigate the hypothesis that the accurate perception of musical metrical structure is related to basic auditory perception of rise time, and also to phonological and literacy development in children.

from Cortex

Rise time perception and detection of syllable stress in adults with developmental dyslexia

To our knowledge this is the first direct demonstration of syllable stress perception deficits in dyslexia. The accurate perception of intonational patterning and rhythm may be critical for the development of the phonological lexicon and consequently for the development of literacy. Even high-functioning compensated adults with dyslexia show impairments in speech processing.

from the Journal of Memory and Language

Potent prosody: Comparing the effects of distal prosody, proximal prosody, and semantic context on word segmentation

Recent work shows that word segmentation is influenced by distal prosodic characteristics of the input several syllables from the segmentation point (Dilley & McAuley, 2008). Here, participants heard eight-syllable sequences with a lexically ambiguous four-syllable ending (e.g., crisis turnip vs. cry sister nip). The prosodic characteristics of the initial five syllables were resynthesized in a manner predicted to favor parsing of the final syllables as either a monosyllabic or a disyllabic word; the acoustic characteristics of the final three syllables were held constant. Experiments 1a–c replicated earlier results showing that utterance-initial prosody influences segmentation utterance-finally, even when lexical content is removed through low-pass filtering, and even when an on-line cross-modal paradigm is used. Experiments 2 and 3 pitted distal prosody against, respectively, distal semantic context and prosodic attributes of the test words themselves. Although these factors jointly affected which words participants heard, distal prosody remained an extremely robust segmentation cue. These findings suggest that distal prosody is a powerful factor for consideration in models of word segmentation and lexical access.

from the Journal of Memory and Language

Words and syllables in fluent speech segmentation by French-learning infants: An ERP study

In order to acquire their native language, infants must learn to identify and segment word forms in continuous speech. This word segmentation ability is thus crucial for language acquisition. Previous behavioral studies have shown that it emerges during the first year of life, and that early segmentation differs according to the language in acquisition. In particular, linguistic rhythm, which differs across classes of languages, has been found to have an early impact on segmentation abilities. For French, behavioral evidence showed that infants could use the rhythmic unit appropriate to their native language (the syllable) to segment fluent speech by 12 months of age, but failed to show whole word segmentation at that age, a surprising delay compared to the emergence of segmentation abilities in other languages. Given the implications of such findings, the present study reevaluates the issue of whole word and syllabic segmentation, using an electrophysiological method, high-density ERPs (event-related potentials), rather than a behavioral technique, and by testing French-learning 12-month-olds on bisyllabic word segmentation. The ERP data show evidence of whole word segmentation while also confirming that French-learning infants rely on syllables to segment fluent speech. They establish that segmentation and recognition of words/syllables happen within 500 milliseconds of their onset, and raise questions regarding the interaction between syllabic segmentation and multisyllabic word recognition.

from Brain Research

Rhythmic motor entrainment in children with speech and language impairments: Tapping to the beat

In prior work (Corriveau et al., 2007), we showed that children with speech and language impairments (SLI) were significantly less sensitive than controls to two auditory cues to rhythmic timing, amplitude envelope rise time and duration. Here we explore whether rhythmic problems extend to rhythmic motor entrainment. Tapping in synchrony with a beat has been described as the simplest rhythmic act that humans perform. We explored whether tapping to a beat would be impaired in children for whom auditory rhythmic timing is impaired. Children with SLI were indeed found to be impaired in a range of measures of paced rhythmic tapping, but were not equally impaired in tapping in an unpaced control condition requiring an internally-generated rhythm. The severity of impairment in paced tapping was linked to language and literacy outcomes.

from Cortex

Perceiving rhythm where none exists: Event-related potential (ERP) correlates of subjective accenting

Previous research suggests that our past experience of rhythmic structure in music results in a tendency for Western listeners to subjectively accent equitonal isochronous sequences. We have shown in an earlier study that the occurrence of a slightly softer tone in the 8th to 11th position of such a sequence evokes a P300 event-related potential (ERP) response of different amplitudes depending on whether the tone occurs in putatively subjectively accented or unaccented sequence positions (Brochard et al., 2003). One current theory of rhythm processing postulates that subjective accenting is the result of predictive modulations of perceptual processes by the attention system. If this is the case then ERP modulations should be observed at an earlier latency than the P300 and these should be observed in ERPs to both standard and softer tones. Such effects were not observed in our previous study. This was possibly due to the use of a linked-mastoid reference which may have obscured lateralized differences. The aim of the present study was to replicate the previous auditory P300 subjective accenting findings and to investigate the possibility that these effects are preceded by ERP changes that are indicative of rhythmic modulation of perceptual processing. Previous auditory P300 findings were replicated. In addition and consistent with current theories of rhythm processing, early brain ERP differences were observed both in standard and deviant tones from the onset of the stimulus. These left lateralized differences are consistent with a rhythmic, endogenously driven, modulation of perception that influences the conscious experience of equitonal isochronous sequences.

from Cortex

Rhythm in the speech of a person with right hemisphere damage: Applying the pairwise variability index

from the International Journal of Speech-Language Pathology

Although several aspects of prosody have been studied in speakers with right hemisphere damage (RHD), rhythm remains largely uninvestigated. This study compares the rhythm of an Australian English speaker with right hemisphere damage (due to a stroke, but with no concomitant dysarthria) to that of a neurologically unimpaired individual. The speakers’ rhythm is compared using the pairwise variability index (PVI) which allows for an acoustic characterization of rhythm by comparing the duration of successive vocalic and intervocalic intervals. A sample of speech from a structured interview between a speech and language therapist and each participant was analysed. Previous research has shown that speakers with RHD may have difficulties with intonation production, and therefore it was hypothesized that there may also be rhythmic disturbance. Results show that the neurologically normal control uses a similar rhythm to that reported for British English (there are no previous studies available for Australian English), whilst the speaker with RHD produces speech with a less strongly stress-timed rhythm. This finding was statistically significant for the intervocalic intervals measured (t(8) = 4.7, p < .01), and suggests that some aspects of prosody may be right lateralized for this speaker. The findings are discussed in relation to previous findings of dysprosody in RHD populations, and in relation to syllable-timed speech of people with other neurological conditions.