- Title
- "Hey Baby! Mummy wants you to be happy and play!": The relationships between maternal pitch contours, infant temperament and symptoms of autism in infancy
- Creator
- Woolard, Alix
- Relation
- University of Newcastle Research Higher Degree Thesis
- Resource Type
- thesis
- Date
- 2020
- Description
- Research Doctorate - Doctor of Philosophy (PhD)
- Description
- Mother-infant interactions during the first year of life are crucial to healthy infant development. The communication that occurs during these interactions involves infant- directed speech (IDS), which contributes to infant language learning, social communication, and emotional development. One aspect that is useful in encouraging infant development, and arguably the most salient aspect of IDS for infants early on, is the prosodic characteristic known as pitch contours. Pitch contours relate to the trajectory of pitch. There are prototypical contours used in IDS which serve different functions like increasing infant arousal or communicating the speaker’s affect. The functions of pitch contours are well known in the literature. It is less known how infant characteristics influence the use of pitch contours by mothers. Two infant characteristics known to influence mother-infant interactions are the infant’s temperament and whether the infant is displaying symptoms of Autism Spectrum Disorder (autism). The aim of the current thesis was to investigate whether infant temperament and early symptoms of autism in young infants (12-months of age) were related to the pitch contours mothers used with them during an interaction. First, a scoping review of the literature was conducted to determine if parents speak differently to infants and children who are diagnosed, or not currently but later diagnosed, with autism. Twenty-seven studies were identified as relevant, and across these studies it was concluded that infants and children diagnosed or later diagnosed with autism do not hear either more or less speech than neurotypical infants. The speech that they do hear, however, may be different in that some studies suggested parents speaking to these infants use more exaggerated acoustic features, use more directive speech, and use more attention-bids during their speech. This scoping review demonstrated the heterogeneity of methodology and results with studies investigating IDS with infants displaying autism features, and recommended more research be undertaken in this arena, which supported the work in this thesis. Second, in a primary study investigating maternal IDS, infant temperament and infant autism symptoms, 109 mother-infant dyads were recruited from three infant development studies at the University of Newcastle Babylab. Infant temperament was assessed via a parent-report questionnaire, the Toddler Temperament Scale (TTS; Fullard et al., 1984), given to the mothers on the day of the appointment. The TTS provided nine domain scores for the infants (activity, rhythmicity, approach, adaptability, mood, intensity, persistence, distractibility, and threshold) as well as a clinical profile (easy, intermediate low, intermediate high, and difficult). Infant autism symptoms were assessed using a parent-report questionnaire, the First Year Inventory (FYI; Reznick et al., 2007). A subset of infants (n=26) also received the observation-based Autism Detection in Early Childhood assessment (ADEC; Young, 2007). Infants received a FYI and ADEC total risk score, as well as a FYI social-communication and FYI sensory regulation score. The mothers’ pitch contours were measured via a recorded 15-minute dyadic play interaction. 36,128 maternal pitch contours were classified into one of nine contour types (rising, bell-shaped, sinusoidal, u-shaped, flat, complex, rapidly-falling, rapidly-rising, and slowly-falling). Spearman’s correlation coefficient was conducted to determine any relationships between maternal pitch contours and infant temperament and infant autism scores. Backwards elimination regressions analyses were conducted on the key variables including known covariates (infant cognitive and language skills, maternal depressive symptoms). Infant temperament was related to maternal pitch contours. Infants rated as having a more negative mood had mothers who used more bell-shaped (r=.22, p=.04), rapidly-falling (r=.27, p=.01), and rapidly-rising contours (r=.24, p=.02). Infant distractibility was related to mothers using fewer flat contours (r=.22, p=.04). Less infant activity was related to mothers using more slowly-falling contours (r=.29, p=.008). Several models of prediction also emerged to explain variance in infant temperament scores. Infant activity scores were predicted by the mother’s use of bell-shaped, complex and slowly-falling contours, "R=.09, F(3, 81)= 3.74, p=.01. Infant rhythmicity scores were predicted via the mother’s depressive symptoms and sinusoidal contours, as well as the number of days the infant was born preterm, R=.19, F(3, 74)= 4.94, p=.004. Infant adaptability was predicted by the mother’s depression symptoms, and her use of sinusoidal and rapidly-falling contours, R= .12, F(3, 44)= 3.04, p=.04. Infant intensity scores were predicted by the number of days the infant was born preterm and the mother’s use sinusoidal contours. Finally, the infants’ mood scores were predicted by the number of days preterm the infant was and also the mother’s use of rapidly- falling contours, r=.12, F(2, 85)= 6.91, p=.002. Infant autism symptoms were also related to maternal pitch contours. Mothers used fewer sinusoidal contours when their infant displayed more autism symptoms (r=-.30, p=.004) and more autism-related sensory regulation issues (r=-.31, p=.001). Mothers also used fewer flat contours if their infant displayed more autism symptoms (r=-.39, p=.04). Again, several models of prediction emerged from the key study variables that explained variance in infant autism symptoms. Infant FYI total score was predicted via the mother’s depression symptoms and number of utterances she used during the interaction, as well as the infant’s cognitive score on a developmental assessment, R=. 34 F(3, 47)= 9.58, p<.0001. Infant social communication score on the FYI was predicted by the mother’s depression score as well as the number of utterances she spoke and her use of flat contours, R=.28 F(3, 47)= 7.46, p=.0003. Infant sensory regulation score on the FYI was predicted by the mother’s depressive symptoms, and her rising and sinusoidal contours as well as the infant’s cognitive score on a developmental assessment, R=.20 F(4, 46)= 4.22, p=.005. Finally, the infants’ score on the ADEC was predicted by the mother’s rising, bell-shaped, flat and complex contours as well as the infant’s language skills, R=.70 F(5, 20)= 12.48, p<.0001. This thesis provides the first evidence that maternal pitch contours are related to infant temperament and early autism symptoms in infancy. The functions thought to underpin the relationships between the infant characteristics and the maternal pitch contours are discussed in detail. These results support the theory that mother-infant interactions are bidirectional, with both the mother and the infant playing active roles. Further research into mother-infant interactions, IDS, pitch contours and the influence of infant characteristics is recommended. These results could inform or support early parent-training interventions involving the use of IDS to target early relationship, language, socio-communication difficulties, as well as improving the outcomes of infants displaying autism symptoms.
- Subject
- infant-directed speech; mother-infant interactions; Newcastle Babylab; autism
- Identifier
- http://hdl.handle.net/1959.13/1418200
- Identifier
- uon:37310
- Rights
- Copyright 2020 Alix Woolard
- Language
- eng
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