Skip to Main content Skip to Navigation
Theses

Symphonie des oscillations cérébrales lors de la perception de la parole : études comportementale et en magnétoencéphalographie chez les enfants neurotypiques et dysphasiques

Abstract : Current models of speech perception suggest a close correspondence between brain rhythms, characterized by neuronal oscillations, and speech rhythm, which would allow the brain to parse the incoming speech signal into relevant linguistic units for decoding. Slow amplitude modulations in speech temporal envelope, which convey syllabic and prosodic information, have been shown to entrain oscillatory activity of auditory cortex in the theta frequency band (4-7 Hz), sampling the acoustic signal into syllable-sized units. Temporal information in speech is a foundation for oral language acquisition and development; accordingly, deficits in processing speech rhythmic cues have been described in developmental language disorders. This thesis sought to throw light on the neurocognitive processes underlying the perception of natural speech in children with typical and atypical language development (Specific Language Impairment – SLI – or Developmental Language Disorder – DLD) in three experimental studies. In a first magnetoencephalography (MEG) study, we unraveled the oscillatory dynamics in a group of French-speaking typically-developing children aged 8 to 13 years old during listening to naturally-produced sentences either at a normal or fast rate. Our results suggested two types of entrainment of cortical oscillations on the temporal envelope of normal rate speech: the first one occurred in the theta band in right auditory cortex whereas the second one was found in a frequency band centered on the mean syllabic rate of our stimuli in left anterior temporal regions. As to the fast rate condition, we showed cortico-acoustic coupling in the theta band in left (pre)motor areas, reflecting the role of the sensorimotor dorsal pathway in challenging listening conditions as well as in language development. In two other studies, we tested the hypothesis of an impairment to process speech syllabic rhythm, potentially underpinned by atypical oscillatory cortical dynamics, in children with developmental language disorders mainly at the expressive level. In a behavioral study, we examined how French-speaking children with expressive DLD (8-13 years old) processed speech naturally produced at a normal or fast rate, or artificially accelerated. Our results showed poorer performance to decode fast sentences, either accelerated naturally or artificially, in these children as compared to their typically-developing peers, which suggests a deficit in extracting speech syllabic information with increased modulation frequency in the amplitude envelope. The last study, identical to the first one in MEG conducted in typically-developing children, provided the first piece of evidence in favor of this interpretation by showing atypical cortical processing of syllabic information in children with DLD, which may account for the phonological and morpho-syntactic deficits frequently described in this developmental disorder. Reduced alignment of theta oscillatory activity in auditory cortex to normal rate speech has indeed been evidenced in children with DLD as compared to typically-developing children. Lack of synchronization of oscillations in left (pre)motor regions to amplitude envelope of fast rate sentences was also observed, which we interpreted as potential dysfunction of the dorsal stream in this population. To the best of our knowledge, the findings obtained in this thesis therefore provide first experimental evidence for (i) coupling between brain rhythms and rhythm of naturally produced speech in typically-developing children and (ii) atypical oscillatory cortical dynamics underlying normal and fast rate speech in children with developmental language disorders.
Document type :
Theses
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-01887759
Contributor : Abes Star :  Contact
Submitted on : Thursday, October 4, 2018 - 2:33:12 PM
Last modification on : Wednesday, November 20, 2019 - 7:53:27 AM
Long-term archiving on: : Saturday, January 5, 2019 - 3:22:57 PM

File

these_internet_guiraud_h.pdf
Version validated by the jury (STAR)

Identifiers

  • HAL Id : tel-01887759, version 1

Collections

Citation

Hélène Guiraud. Symphonie des oscillations cérébrales lors de la perception de la parole : études comportementale et en magnétoencéphalographie chez les enfants neurotypiques et dysphasiques. Psychologie. Université de Lyon, 2017. Français. ⟨NNT : 2017LYSE2139⟩. ⟨tel-01887759⟩

Share

Metrics

Record views

256

Files downloads

123