Évaluation électrophysiologique auditive et examen du langage et de l’attention chez l’enfant né prématurément et l’enfant né à terme

L’objectif de cette thèse est l’étude du développement de l’attention auditive et des capacités de discrimination langagière chez l’enfant né prématurément ou à terme. Les derniers mois de grossesse sont particulièrement importants pour le développement cérébral de l’enfant et les conséquences d’une naissance prématurée sur le développement peuvent être considérables. Les enfants nés prématurément sont plus à risque de développer une variété de troubles neurodéveloppementaux que les enfants nés à terme. Même en l’absence de dommages cérébraux visibles, de nombreux enfants nés avant terme sont à risque de présenter des troubles tels que des retards langagiers ou des difficultés attentionnelles. Dans cette thèse, nous proposons donc une méthode d’investigation des processus préattentionnels auditifs et de discrimination langagière, à l’aide de l’électrophysiologie à haute densité et des potentiels évoqués auditifs (PEAs). Deux études ont été réalisées. La première visait à mettre sur pied un protocole d’évaluation de l’attention auditive et de la discrimination langagière chez l’enfant en santé, couvrant différents stades de développement (3 à 7 ans, 8 à 13 ans, adultes ; N = 40). Pour ce faire, nous avons analysé la composante de Mismatch Negativity (MMN) évoquée par la présentation de sons verbaux (syllabes /Ba/ et /Da/) et non verbaux (tons synthétisés, Ba : 1578 Hz/2800 Hz ; Da : 1788 Hz/2932 Hz). Les résultats ont révélé des patrons d’activation distincts en fonction de l’âge et du type de stimulus présenté. Chez tous les groupes d’âge, la présentation des stimuli non verbaux a évoqué une MMN de plus grande amplitude et de latence plus rapide que la présentation des stimuli verbaux. De plus, en réponse aux stimuli verbaux, les deux groupes d’enfants (3 à 7 ans, 8 à 13 ans) ont démontré une MMN de latence plus tardive que celle mesurée dans le groupe d’adultes. En revanche, en réponse aux stimuli non verbaux, seulement le groupe d’enfants de 3 à 7 ans a démontré une MMN de latence plus tardive que le groupe d’adulte. Les processus de discrimination verbaux semblent donc se développer plus tardivement dans l’enfance que les processus de discrimination non verbaux. Dans la deuxième étude, nous visions à d’identifier les marqueurs prédictifs de déficits attentionnels et langagiers pouvant découler d’une naissance prématurée à l’aide des PEAs et de la MMN. Nous avons utilisé le même protocole auprès de 74 enfants âgés de 3, 12 et 36 mois, nés prématurément (avant 34 semaines de gestation) ou nés à terme (au moins 37 semaines de gestation). Les résultats ont révélé que les enfants nés prématurément de tous les âges démontraient un délai significatif dans la latence de la réponse MMN et de la P150 par rapport aux enfants nés à terme lors de la présentation des sons verbaux. De plus, les latences plus tardives de la MMN et de la P150 étaient également corrélées à des performances langagières plus faibles lors d’une évaluation neurodéveloppementale. Toutefois, aucune différence n’a été observée entre les enfants nés à terme ou prématurément lors de la discrimination des stimuli non verbaux, suggérant des capacités préattentionnelles auditives préservées chez les enfants prématurés. Dans l’ensemble, les résultats de cette thèse indiquent que les processus préattentionnels auditifs se développent plus tôt dans l'enfance que ceux associés à la discrimination langagière. Les réseaux neuronaux impliqués dans la discrimination verbale sont encore immatures à la fin de l'enfance. De plus, ceux-ci semblent être particulièrement vulnérables aux impacts physiologiques liés à la prématurité. L’utilisation des PEAs et de la MMN en réponse aux stimuli verbaux en bas âge peut fournir des marqueurs prédictifs des difficultés langagières fréquemment observées chez l’enfant prématuré.The aim of this thesis is to investigate early auditory attention and language development in full-term and preterm children. The last months of pregnancy are particularly important for the child’s cerebral development, and the impacts of a premature birth on his/her neurodevelopment can be substantial. Prematurely born children are at higher risk of developing a variety of neurodevelopmental disorders compared to full-terms. Even without visible brain injury, many premature children are at risk of presenting disorders such as language delays and attentional difficulties. In this thesis, we suggest an approach to investigate pre-attentional processes and early language discrimination abilities in infants using high-density electrophysiology and auditory event-related potentials (AERPs). We conducted two studies. The first one aimed at establishing a paradigm to evaluate auditory attention and language discrimination development in healthy full-term children, over different developmental stages (3 to 7 years, 8 to 13 years, adults; N = 40). To do so, we analyzed the Mismatch Negativity (MMN) component in response to speech (spoken syllables /Ba/ and /Da/) and non-speech stimuli (frequency-synthesized tones, Ba: 1578 Hz/2800 Hz; Da: 1788 Hz/2932 Hz). Distinct patterns of activation were revealed according to stimulus type and age. In all groups, non-speech stimuli elicited an MMN of larger amplitude and earlier latency than did the presentation of speech stimuli. Moreover, in response to speech stimuli, both children groups (3 to 7 years, 8 to 13 years) showed a significantly delayed MMN response compared to the adults group. In contrast, in response to non-speech stimuli, only the youngest group (3 to 7 years) showed a significantly delayed MMN compared to the adults. Age-related differences for tone discrimination therefore appear to occur earlier in children’s development than do the discriminative processes for speech sounds. In the second study, we aimed at identifying the electrophysiological markers of auditory attention and language deficits often incurred by a premature birth. We thus presented this paradigm to 74 infants born preterm (before 34 gestational weeks) or full-term (at least 37 gestational weeks), aged 3, 12 and 36 months old. Our results indicated that preterm children of all age groups showed a significantly delayed MMN and P150 responses to speech stimuli compared to full-terms. Moreover, significant correlations were found between the delayed MMN and P150 responses to speech sounds and lower language scores on a neurodevelopmental assessment. However, no significant differences were found between full-term and preterm children for the MMN in response to non-speech stimuli, suggesting preserved pre-attentional auditory discrimination abilities in these children. Altogether, the findings from this thesis indicate that the neurodevelopmental processes associated with auditory pre-attentional skills occur earlier in childhood compared to language discrimination processes. Cerebral networks involved in speech discrimination are still immature in late childhood. Furthermore, neural networks involved in speech discrimination and language development also appear to be particularly vulnerable to the impacts of prematurity. The use of AERPs and the MMN response to speech stimuli in infancy can thus provide predictive markers of language difficulties commonly seen in premature infants

The role of parenting stress in anxiety and sleep outcomes in toddlers with congenital heart disease

ObjectivesThis retrospective cohort study investigates how parenting stress, measured at 4 months of age by use of a classic three-dimensional parent-reported scale (Parenting Stress Index, 4th Ed. or PSI-4), can predict anxiety symptoms and quality of sleep at 24 months in toddlers with congenital heart disease (CHD).Study DesignSixty-six toddlers with CHD followed at our cardiac neurodevelopmental follow-up clinic were included in this study. As part of their systematic developmental assessment program, parents completed questionnaires on their stress level (PSI-4) when their child was 4 months old, and on their child's anxiety symptoms and quality of sleep at 24 months. Eight multiple linear regression models were built on the two measures collected at 24 months using the PSI-4 scores collected at 4 months. For each measure, four models were built from the PSI-4 total score and its three subscales (Parental Distress, Parent-Child Dysfunctional Interaction, Difficult Child), controlling for sex and socioeconomic status.ResultsThe PSI-4 Difficult Child subscale, which focuses on parenting anxiety related to the child's behavioral problems and poor psychosocial adjustment, accounted for 17% of the child's anxiety symptoms at 24 months. The two other PSI-4 subscales (Parental Distress and Parent-Child Dysfunctional Interaction) and the PSI-4 total score did not contribute significantly to the models. None of the four regression models on perceived quality of sleep were significant. It is important to note that 33% of parents responded defensively to the PSI-4.ConclusionsParenting stress related to the child's behavioral problems and poor psychosocial adjustment, measured when the child is 4 months old, is associated with the child's ulterior anxiety symptoms. As very few standardized tools are available to assess the behavioral and psychoaffective development of infants, this study highlights the importance of early psychosocial screening in parents of infants with CHD. The high rate of significant Defensive Responding Indices reminds us to not take parent reports at face value, as their actual stress levels might be higher

The Mediating Role of Dispositional Mindfulness in the Associations Between Intimate Violence, Self-esteem, and Distress Among Adolescents

Objectives Although dating violence has been recognized as a major public health issue considering its high prevalence and deleterious consequences, little research has been conducted on the potential mechanisms through which dating violence is associated with negative psychological outcomes. The aim of this study was to test the mediational effect of dispositional mindfulness on the relationship between dating violence (victimization and perpetration), psychological distress, and self-esteem by including measures of both current and previous dating violence and by controlling for gender, age, and dating relationship length. Methods The sample consisted of 227 adolescents (127 girls and 100 boys) aged between 15 and 17 old recruited in a small urban area. They completed measures of previous and current experiences of dating victimization and perpetration, the K10 psychological distress scale, the Self-Description Questionnaire which measures self-esteem, and the Child and Adolescent Mindfulness Measure. Results The results showed that previous dating violence victimization was associated with lower dispositional mindfulness, which in turn was related to lower self-esteem and higher psychological distress, suggesting a mediation through dispositional mindfulness. However, in the integrative model, previous dating violence perpetration was not associated with dispositional mindfulness, self-esteem, or psychological distress. Conclusions These results indicate the importance of previous dating violence victimization and its association with lower dispositional mindfulness, leading to lower self-esteem and higher psychological distress in teenagers

A Parent–child yoga intervention for reducing attention deficits in children with congenital heart disease: the Yoga for Little Hearts Feasibility Study Protocol

Introduction Preschoolers and school-aged children with congenital heart disease (CHD) are at higher risk of attention deficit hyperactivity disorder (ADHD) compared with the general population. To this day, no randomised controlled trial (RCT) aiming to improve attention has been conducted in young children with CHD. There is emerging evidence indicating that parent–child yoga interventions improve attention and reduce ADHD symptoms in both typically developing and clinical populations.Methods and analysis This is a single-blind, two-centre, two-arm trial during which 24 children with CHD and their parents will be randomly assigned to (1) a parent–child yoga intervention in addition to standard clinical care or (2) standard clinical care alone. All participants will undergo standardised assessments: (1) at baseline, (2) immediately post-treatment and (3) 6 months post-treatment. Descriptive statistics will be used to estimate the feasibility and neurodevelopmental outcomes. This feasibility study will evaluate: (1) recruitment capacity; (2) retention, drop-out and withdrawal rates during the yoga programme and at the 6-month follow-up; (3) adherence to the intervention; (4) acceptability of the randomisation process by families; (5) heterogeneity in the delivery of the intervention between instructors and use of home-based exercises between participants; (6) proportion of missing data in the neurodevelopmental assessments and (7) SD of primary outcomes of the full RCT in order to determine the future appropriate sample size.Ethics and dissemination Ethical approval has been obtained by the Research Ethics Board of the Sainte-Justine University Hospital. The findings will be disseminated in peer-reviewed journals and conferences and presented to the Canadian paediatric grand round meetings.Trial registration number NCT05997680