Early vocalization of preterm infants with extremely low birth weight (ELBW), Part I: From birth to expansion stage

Babbling in extremely premature infants at 12 months corrected age

Babbling is an important precursor to speech in infancy, and deviations from the typical babbling development can predict later difficulties in speech, language, and communication. This cross-sectional study aimed to investigate babbling and early speech in Swedish extremely premature infants. Samples of babbling were collected from 20 extremely premature infants (EPT group) at the corrected age of 12 months. Data collection was home-based and consisted of an audio-video recording of each infant playing with a parent. Presence of canonical babbling (CB), and three oral stop variables distinctive of typical babbling, and consonant inventory were assessed. The assessment was performed during a standardised observation of babbling. Data from the EPT group were compared to previously collected data of a reference group of 20 10-month-old infants without known medical diagnoses. The results showed that the EPT group had a lower proportion of infants producing CB, and that they used a significantly smaller consonant inventory compared to the reference group. Although not statistically significant, oral stops were less frequently found in the EPT group. The findings of a restricted consonant inventory and low proportion of CB in the EPT group are not surprising considering that the group has been found to be at risk of speech and language delay in toddlerhood. Still, further research is needed to explore whether babbling at 12 months can predict speech and language skills at an older age in extremely premature infants.

Vocal Characteristics of Infants at Risk for Speech Motor Involvement: A Scoping Review

PURPOSE

The purpose of this scoping review was to (a) summarize methodological characteristics of studies examining vocal characteristics of infants at high risk for neurological speech motor involvement and (b) report the state of the high-quality evidence on vocal characteristic trends of infants diagnosed or at high risk for cerebral palsy (CP).

METHOD

The PRISMA (Preferred Reporting Items of Systematic Reviews and Meta-Analyses) extension for scoping reviews was followed for reporting our review. Studies measured prelinguistic vocal characteristics of infants under 24 months with birth risk or genetic conditions known to commonly present with speech motor involvement. Fifty-five studies met criteria for Part 1. Eleven studies met criteria for synthesis in Part 2.

RESULTS

A smaller percentage of studies examined infants with or at risk for CP compared to studies examining genetic conditions such as Down syndrome. The median year of publication was 1999, with a median sample size of nine participants. Most studies were conducted in laboratory settings and used human coding of vocalizations produced during caregiver-child interactions. Substantial methodological differences were noted across all studies. A small number of high-quality studies of infants with or at risk for CP revealed high rates of marginal babbling, low rates of canonical babbling, and limited consonant diversity under 24 months. Mixed findings were noted across studies of general birth risk factors.

CONCLUSIONS

There is limited evidence available to support the early detection of speech motor involvement. Large methodological differences currently impact the ability to synthesize findings across studies. There is a critical need to conduct longitudinal research with larger sample sizes and advanced, modern technologies to detect vocal precursors of speech impairment to support the accurate diagnosis and prognosis of speech development in infants with CP and other clinical populations.

Inter-rater reliability in classification of canonical babbling status based on canonical babbling ratio in infants with isolated cleft palate randomised to Timing of Primary Surgery for Cleft Palate (TOPS)

Canonical babbling (CB) is commonly defined as present when at least 15% of all syllables produced are canonical, in other words a canonical babbling ratio (CBR) ≥0.15. However, there is limited knowledge about inter-rater reliability in classification of CB status based on CBR and inter-rater differences in assessment of CBR. We investigated inter-rater reliability of experienced Speech Language Therapists (SLTs) on: classification of CB status based on CBR ≥ 0.15, CBRs and the total number of syllables per infant used to calculate CBR.Each infant (n = 484) was video-recorded at a clinical site in play interaction with their parent as part of the randomised controlled trial Timing of Primary Surgery for Cleft Palate. Each recording was subsequently assessed by three independent SLTs, from a pool of 29 SLTs. They assessed the recordings in real time.The three assessing SLTs agreed in classification of CB status in 423 (87.4%) infants, with higher complete agreement for canonical (91%; 326/358) than non-canonical (77%; 97/126). The average difference in CBR and total number of syllables identified between the SLT assessments of each infant was 0.12 and 95, respectively.This study provided new evidence that one trained SLT can reliably classify CB status (CBR ≥ 0.15) in real time when there is clear distinction between the observed CBR and the boundary (0.15); however, when the observed CBR approaches the boundary multiple SLT assessments are beneficial. Thus, we recommend to include assessment of inter-rater reliability, if the purpose is to compare CBR and total syllable count across infants or studies.Trial registration number here: www.clinicaltrials.gov, identifier NCT00993551.

Early Speech Sound Production and Its Trajectories in Very Preterm Children From 2 to 4 Years of Age

PURPOSE

Very preterm (VPT) children are at risk for speech and language problems throughout school age. However, little is known about early speech sound production in these children. This study aims to present a detailed description of early speech sound production and its trajectories in VPT children from 2 to 4 years of age. In addition, this study aimed to determine if early speech sound production is associated with speech production and expressive language function at 4 years of age.

METHOD

In 63 VPT children (< 32 weeks of gestation, 41 boys, mean gestational age = 28.8 weeks, mean birth weight = 1,135 g), speech sound production was assessed by naturalistic speech analysis at 2 years of corrected age and speech and language function by standardized tests at 4 years of age.

RESULTS

Speech sound production was found to be abnormal in 49% of the VPT children at 2 years of age and in 19% at 4 years of age. Four different speech production trajectories from 2 to 4 years of age could be identified: a normal trajectory, an abnormal trajectory, a catch-up trajectory, and a growing-into-deficit trajectory. Early speech production, defined by the number of acquired consonants at 2 years of age, significantly predicted the word production score at 4 years of age and the sentence production score at 4 years of age.

CONCLUSIONS

Compared to the general population, an alarmingly high proportion of VPT children showed speech production problems at 2 years of age. About half of these children showed persistent speech problems at 4 years of age. Moreover, these problems were associated with expressive language problems at the age of 4 years.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19310822.

A Study of Maternal Competence in Preterm Birth Condition, during the Transition from Hospital to Home: An Early Intervention Program's Proposal

The study was conducted with 104 mothers (average age 32.5 years, SD 6.1) of preterm infants (very and moderately preterm but still healthy) to monitor the perceived maternal role competence from the time of hospitalisation to post-discharge, in order to define an intervention program to support mothers during this transition. A targeted Q-Sort tool (Maternal Competence Q-Sort in preterm birth) was applied at two different times as a self-observation tool for parenting competence in neonatology. A tendency towards dysregulation of the maternal role competence was detected, mainly in terms of low self-assessment and was found to worsen during post-discharge, particularly with regard to caregiving ability. This study suggests the importance of accompanying parenting competence in preterm birth conditions, not only during hospitalisation in the Neonatal Intensive Care Unit (NICU) but also following discharge in order to promote the development of premature infants. This paper reports in the last part a specific integrated psychoeducational intervention program (psychologist and nurses), which we defined precisely in light of the suggestions offered by the study data on perceived maternal competence created with the Q-sort.

Prelexical phonetic and early lexical development in German-acquiring infants: canonical babbling and first spoken words

Prelexical phonetic capacities have widely been described to be a precursor for later speech and language development. However, studies so far varied greatly in the measurements used for the detection of canonical babbling onset or the description of infants' phonetic capacities at one or more set time points. The comparability of results is, therefore, questionable. Thus, the aims of this study were to investigate the associations between (1) different measurements of CBO, (2) different aspects of phonetic capacity at the age of 9 months and (3) age of CBO and phonetic capacities at 9 months. A further aim (4) was to explore whether one of the measures would be suitable to predict the age of word onset (WO) in 20 healthy German-acquiring individuals. The data were derived from monthly recorded spontaneous speech samples between 0 and 18 months. It was found that the different applied prelexical measures equally well serve as valid estimators for the detection of CBO or of infants' phonetic capacities. Further, age of CBO and phonetic capacities at 9 months were significantly associated even though the age of CBO did not reliably predict phonetic capacities. Prelexical measures and WO were not related. Reasons for no indication of a significant association are discussed.

The Relationship Between the Onset of Canonical Syllables and Speech Perception Skills in Children With Cochlear Implants

Purpose The study sought to determine whether the onset of canonical vocalizations in children with cochlear implants (CIs) is related to speech perception skills and spoken vocabulary size at 24 months postactivation. Method The vocal development in 13 young CI recipients (implanted by their third birthdays; mean age at activation = 20.62 months, SD = 8.92 months) was examined at every 3-month interval during the first 2 years of CI use. All children were enrolled in auditory-oral intervention programs. Families of these children used spoken English only. To determine the onset of canonical syllables, the first 50 utterances from 20-min adult-child interactions were analyzed during each session. The onset timing was determined when at least 20% of utterances included canonical syllables. As children's outcomes, we examined their Lexical Neighborhood Test scores and vocabulary size at 24 months postactivation. Results Pearson correlation analysis showed that the onset timing of canonical syllables is significantly correlated with phonemic recognition skills and spoken vocabulary size at 24 months postactivation. Regression analyses also indicated that the onset timing of canonical syllables predicted phonemic recognition skills and spoken vocabulary size at 24 months postactivation. Conclusion Monitoring vocal advancement during the earliest periods following cochlear implantation could be valuable as an early indicator of auditory-driven language development in young children with CIs. It remains to be studied which factors improve vocal development for young CI recipients.

Uneven Linguistic Outcome in Extremely Preterm Children

One primary problem in extremely preterm children is the occurrence of atypical language development. The aim of this study was to explore the components of language (articulatory phonetics, lexicon and syntax) in comprehension and production in extremely preterm children between the 4th and 5th year of age. The language section of the Preschool Neuropsychological Test was administered to 20 extremely preterm monolingual Italian children (GA < 28 weeks) and to a control sample of 40 full term children (GA > 37 weeks), matched for age and non-verbal IQ. Language comprehension was fully efficient in all of the components that we assessed. In the tasks of language production the clinical sample fared much worse than their age and IQ matched controls and the differences were highly significant (p < .001). Language acquisition in extremely preterm children may follow uneven developmental trajectories: language comprehension can be spared in the face of a selective impairment of language production at the level of articulatory phonetics and syntax.

Language Origins Viewed in Spontaneous and Interactive Vocal Rates of Human and Bonobo Infants

From the first months of life, human infants produce "protophones," speech-like, non-cry sounds, presumed absent, or only minimally present in other apes. But there have been no direct quantitative comparisons to support this presumption. In addition, by 2 months, human infants show sustained face-to-face interaction using protophones, a pattern thought also absent or very limited in other apes, but again, without quantitative comparison. Such comparison should provide evidence relevant to determining foundations of language, since substantially flexible vocalization, the inclination to explore vocalization, and the ability to interact socially by means of vocalization are foundations for language. Here we quantitatively compare data on vocalization rates in three captive bonobo (Pan paniscus) mother-infant pairs with various sources of data from our laboratories on human infant vocalization. Both humans and bonobos produced distress sounds (cries/screams) and laughter. The bonobo infants also produced sounds that were neither screams nor laughs and that showed acoustic similarities to the human protophones. These protophone-like sounds confirm that bonobo infants share with humans the capacity to produce vocalizations that appear foundational for language. Still, there were dramatic differences between the species in both quantity and function of the protophone and protophone-like sounds. The bonobo protophone-like sounds were far less frequent than the human protophones, and the human protophones were far less likely to be interpreted as complaints and more likely as vocal play. Moreover, we found extensive vocal interaction between human infants and mothers, but no vocal interaction in the bonobo mother-infant pairs-while bonobo mothers were physically responsive to their infants, we observed no case of a bonobo mother vocalization directed to her infant. Our cross-species comparison focuses on low- and moderate-arousal circumstances because we reason the roots of language entail vocalization not triggered by excitement, for example, during fighting or intense play. Language appears to be founded in flexible vocalization, used to regulate comfortable social interaction, to share variable affective states at various levels of arousal, and to explore vocalization itself.

Volubility of the human infant: Effects of parental interaction (or lack of it)

Although parental volubility, or amount of talk, has received considerable recent attention, infant volubility has received comparatively little attention despite its potential significance for communicative risk status and later linguistic and cognitive outcomes. Volubility of 16 typically developing infants from 2 to 11 months of age was longitudinally investigated in the present study across three social circumstances: parent talking to infant, parent not talking to infant and parent talking to interviewer while the infant was in the room. Results indicated that volubility was least in the Interview circumstance. There were no significant differences in volubility between the parent Talk and No Talk circumstances. Volubility was found to reduce with age. These results suggest that infants vocalise in a variety of circumstances, even when no one talks to or interacts with them. The presence of a stranger or perhaps overhearing adults speaking to each other, however, may significantly reduce infant volubility.

Early vocalization of preterm infants with extremely low birth weight (ELBW), Part II: From canonical babbling up to the appearance of the first word

The aim of this study was to systematically describe the preverbal development of preterm infants from canonical babbling up to the first word and to compare it with that of healthy full-term infants. In addition, the amount of vocalization between the preterm and full-term groups was compared. The sample consisted of 18 preterm infants with extremely low birth weight and 11 full-term infants. The development of preverbal vocalization before variegated babbling did not differ between the groups. Instead, the preterm infants failed to produce more different kinds of canonical syllable types than the full-term infants. However, they showed a larger variance of variegated babbling skills and remained in the babbling phase longer before reaching the first meaningful word compared with the full-term infants. Following the onset of canonical babbling, the preterm infants produced fewer vocalizations than the full-term infants and they reached the first word later than the full-term infants.