L’environnement (E) du grand prématuré (GP) diffère de l’E. utérin et contribue aux séquelles neurosensorielles qui le menace. Les stimuli auditifs y sont prédominants et atypiques. Peu de choses sont connues sur la sensibilité auditive du GP à ces stimuli. Elle est évaluée ici par l’analyse de sa réactivité physiologique, comportementale, et cérébrale (NIRS) aux variations de cet E. Une étude observationnelle montre que i) le GP réagit à des stimuli auditifs dès un seuil de 5-10 dBA de ratio signal-bruit ambiant ; ii) certaines stimulations altèrent son bien-être (désaturations, rupture du sommeil) ; iii) ses réponses autonomiques sont les plus sensibles. Sa réactivité varie selon la source sonore, suggérant une discrimination du caractère vocal ou non des stimuli. Une étude expérimentale évalue d’autres aspects de ses performances auditives (impact de la fréquence sonore, de la valence émotionnelle des voix) et leur maturation de 30-32 à 34-36 sem. d’âge post-menstruel. Son champ de perception fréquentiel de sons purs s’élargit des moyennes (500-2500 Hz) aux basses et hautes fréquences (100 et 4500 Hz). Après 34 sem., il discrimine la voix maternelle de celle d’une autre mère et d’une autre femme (émotionnellement neutre). Cette réactivité préférentielle se traduit par un « réflexe cardiaque d’orientation » et témoigne qu’un GP soustrait précocement à la voix de sa mère développe des capacités perceptives similaires à celles du fœtus exposé en continue à la prosodie de la voix maternelle. Ces résultats ouvrent un champ de recherche complémentaire sur les conséquences à long terme de son expérience auditive précoce (attachement, développement du langage et des émotions). / The environment (E) of very preterm infant (VPI) greatly differs from the uterine E and contributes to his risk of altered neurodevelopment. Although auditory stimuli are prominent and atypical in the NICU, little is known about the auditory sensitivity of VPI to his acoustic E. It is evaluated through their physiological, behavioral, and brain (NIRS) responsiveness to auditory environmental changes. An observational study shows that i) VPIs respond to “naturalistic” auditory stimuli from a minimum signal-to-noise ratio threshold of 5-10 dBA, ii) some stimuli can affect their well-being (desaturation, sleep disruption), iii) their autonomic reactivity is the most sensitive. Their reactivity varies depending on the sound sources, suggesting an ability to discriminate vocal from non vocal sounds. An experimental approach assess other aspects of their auditory performance (impact of sound frequency, emotional valence of voices) and their maturation from 30-32 to 34-36 wks post-menstrual age. Their perceptual field of sound frequencies expands for pure tones from the middle frequencies (500-2500 Hz) to low and high frequencies (100 and 4500 Hz). After 34 wks, VPIs discriminate their mother's voice from that of another mother and of another woman (emotionally neutral). This preferential reactivity relies on a "cardiac orienting reflex" suggesting that VPI not exposed for weeks to their mother’s voice in utero, can develop perceptual abilities similar to those of the fetuses continuously exposed to the prosody of their mother’s voice. They open ways for further research on the long-term consequences of early auditory experience (attachment, language and emotions development).

Made available in DSpace on 2016-07-27T14:20:49Z (GMT). No. of bitstreams: 1 Ocania da Costa Vale.pdf: 463237 bytes, checksum: 5b5deb15061b023bdcbbca6a38187bb9 (MD5) Previous issue date: 2006-06-19 / This research intended to verify is the behavior of the newborn indicates recognition of motherese maternal. Subjects were twenty normal newborn babies (seven female and thirteen male) with average weight of 3,300Kg and Apgar score of nine on the first and fifth minutes of life. The experiment used a multiple ABA or reversion design, alternating between periods of base-line and periods of verbal stimulation. Behavioral data were obtained through direct observation using behavioral sampling with fixed time interval. Recorded behaviors were: Orientation, Attention, Body movements, Crying, Vocalization and Non-nutritional suction. In this study, the variation of Orientation, through out the session, suggests that habituation occurred for female Motherese in general, especially for the maternal voice. Body movements indicate relation between the stimulus and the expectation of successive events, indicating recognition of maternal motherese. Cry response indicates a tendency to discriminate the infantilization of the maternal voice and also hold a singular relation with maternal verbal behavior during gestation. The occurrence Vocalizations in response to motherese might be related to the development of the emotional processing the language. The occurrence of Non-nutritional suction demonstrates the ability of the newborn to associate environmental stimulus to the received cares. / Esta pesquisa pretendeu identificar os comportamentos do recém-nascido, indicadores de discriminação da infantilização da voz materna. Participaram deste estudo vinte recém-nascidos ouvintes normais, sendo sete do sexo feminino e treze do sexo masculino com idade média de 26h36min de vida, peso médio de 3,300 Kg e escore de Apgar 9 no primeiro e 10 no quinto minuto de vida. O experimento foi desenhado segundo o delineamento ABA múltiplo ou de reversão, alternando entre períodos de linhas de base e períodos de estimulação verbal. Os dados comportamentais foram obtidos por meio da observação direta usando o método de amostragem com intervalo de tempo. Os comportamentais registrados foram: Orientação, Atenção, Movimentos corporais, Choro, Vocalização e Sucção não-nutritiva. Neste estudo, a variação de Orientação, ao longo da sessão, sugere que a habituação ocorreu, em geral, diante da infantilização das vozes femininas, especialmente diante da voz materna. Os Movimentos corporais indicam a relação entre o estímulo percebido e a expectativa dos eventos sucessivos indicando o reconhecimento da infantilização da voz materna. A resposta do Choro indicou a tendência de discriminação da infantilização da voz materna e, também, apresentou uma singular relação com a conduta verbal da mãe durante a gestação. A ocorrência da Vocalização diante das vozes infantilizadas pode associar-se ao desenvolvimento do processamento emocional da linguagem. A produção de Sucção não-nutritiva demonstra a habilidade do recém-nascido de associar estímulos ambientais aos cuidados recebidos.