Using Eye Movements to Assess Language Comprehension in Toddlers Born Preterm and Full Term

Early language processing efficiency and pre-literacy outcomes in children born full term and preterm

Language processing efficiency-that is, the skill at processing language in real time-assessed in toddlerhood is associated with later language outcomes in children born full term (FT) and preterm (PT) during school age. No studies to date have assessed patterns of relations between early language processing efficiency and pre-literacy skills, such as print knowledge and phonological awareness, and whether relations are similar in FT and PT children. In this study, participants (N = 94, 49 FT and 45PT) were assessed in the looking-while-listening (LWL) task at 18 months of age (corrected for degree of prematurity), deriving measures of processing speed and accuracy. At 4½ years of age, children were assessed on standardized tests of print knowledge, phonological awareness, and expressive language. Processing speed and accuracy predicted both pre-literacy outcomes (r2 change = 7.8%-19.5%, p < .01); birth group did not moderate these effects. Relations were significantly reduced when controlling for expressive language. Thus, early language processing efficiency supports later expressive language abilities, which in turn supports developing pre-literacy skills. Processing speed and phonological awareness were also directly related, indicating an independent role for processing speed in literacy development. Mediation effects were not moderated by birth group, suggesting a similar developmental pathway in FT and PT children.

Associations between early efficiency in language processing and language and cognitive outcomes in children born full term and preterm: similarities and differences

Associations between children's early language processing efficiency and later verbal and non-verbal outcomes shed light on the extent to which early information processing skills support later learning across different domains of function. Examining whether the strengths of associations are similar in typically developing and at-risk populations provides an additional lens into the varying routes to learning that children may take across development. In this follow-up study, children born full-term (FT, n = 49) and preterm (PT, n = 45, ≤32 weeks gestational age, birth weight <1800 g) were assessed in the Looking While Listening (LWL) task at 18 months (corrected for degree of prematurity in PT group). This eye-tracking task assesses efficiency of real-time spoken language comprehension as accuracy and speed (RT) of processing. At 4 ½ years, children were assessed on standardized tests of receptive vocabulary, expressive language, and non-verbal IQ. Language processing efficiency was associated with both language outcomes (r2-change: 7.0-19.7%, p < 0.01), after covariates. Birth group did not moderate these effects, suggesting similar mechanisms of learning in these domains for PT and FT children. However, birth group moderated the association between speed and non-verbal IQ (r2-change: 4.5%, p < 0.05), such that an association was found in the PT but not the FT group. This finding suggests that information processing skills reflected in efficiency of real-time language processing may be recruited to support learning in a broader range of verbal and non-verbal domains in the PT compared to the FT group.

Drivers of Lexical Processing and Implications for Early Learning

Understanding words in unfolding speech requires the coordination of many skills to support successful and rapid comprehension of word meanings. This multifaceted ability emerges before our first birthday, matures over a protracted period of development, varies widely between individuals, forecasts future learning outcomes, and is influenced by immediate context, prior knowledge, and lifetime experience. This article highlights drivers of early lexical processing abilities while exploring questions regarding how learners begin to acquire, represent, and activate meaning in language. The review additionally explores how lexical processing and representation are connected while reflecting on how network science approaches can support richly detailed insights into this connection in young learners. Future research avenues are considered that focus on addressing how language processing and other cognitive skills are connected.

Spoken language comprehension in children and adults with Angelman Syndrome

INTRODUCTION

Objective evaluation of receptive communication abilities in nonspeaking individuals using standardized behavioral measures can be complicated by co-occurring intellectual disabilities and motor difficulties. Eye tracking during listening may offer an informative complementary approach to directly evaluate receptive language skills.

METHOD

This study examined feasibility of eye gaze measures as an index of spoken language comprehension in nonspeaking children and adults with Angelman syndrome (AS; n = 23) using a looking-while-listening procedure. Typically developing children (n = 34) provided a reference data set. Primary caregivers of participants with AS completed standardized informant reports (MacArthur-Bates Communicative Development Inventory: Words and Gestures; Vineland Adaptive Behavior Scales-3; Aberrant Behavior Checklist-2) to characterize communicative skills and general adaptive functioning.

RESULTS

Gaze data in participants with AS, particularly in the individuals reported by caregivers to have larger receptive vocabularies and stronger adaptive communicative functioning, demonstrated the expected pattern of comprehension reflected by the increased probability of looks to the target images after vs. before they were named in a spoken sentence. However, processing speed (gaze reaction time) was significantly slower in participants with AS than in the typically developing group.

CONCLUSIONS

Gaze-based paradigms could be an informative measure of receptive communication processes in participants who are unable to complete traditional standardized behavioral assessments.

Eye tracking based assessment of lexical processing and early lexical development in very preterm children

BACKGROUND

Associations between lexical processing and lexical development during the second year of life have been little studied in preterm children.

AIMS

To evaluate associations between lexical processing at 18 months and lexical development between 12 and 18 months in very preterm children.

STUDY DESIGN

Correlational study.

SUBJECTS

25 Finnish-speaking children born <32 gestational weeks.

OUTCOME MEASURES

Lexical processing (reaction time RT; correct looking time CLT) was measured with an eye tracking technology-based task at 18 months' corrected age. Lexical development was measured longitudinally at 12-, 15- and 18-months' corrected age using the following screening instruments: the short form version of the MacArthur Communicative Development Inventories and the Communication and Symbolic Behavior Scale: Infant-Toddler Checklist.

RESULTS

The longer the RT of the child, the weaker expressive skills the child had at 12 and 15 months (correlations coefficient values -0.45 to -0.51). The more the child looked at the target image compared to the distractor (CLT), the stronger expressive skills the child had at 18 months (r = 0.45-0.52). A linear regression model with RT and gender as independent variables explained 33 % of the variance in lexical skills at 18 months. A model with CLT explained 40 % of expressive skills at 18 months.

CONCLUSIONS

Lexical processing at 18 months was associated with expressive lexical development in very preterm children. The results suggest eye tracking technology based methods may have utility in the assessment of early lexical growth in preterm children, although further research is needed to assess psychometric properties and predictive value of the method.

Immaturity of Oculomotor Capabilities During a Reading Task in Children Born Prematurely: An Eye Tracker Study

To our knowledge, there are no studies recording the reading eye movements of children born prematurely. We examined the oculomotor patterns during reading of 23 children born prematurely ( M age = 7.8, SD = 0.2 years) to compare them with those from two groups of children born at full-term who were matched for chronological age or reading age, respectively. We found the oculomotor reading pattern in children who were preterm to be similar to that of children who were full-term and matched for reading age; this shared pattern was characterized by longer duration of fixations, frequent prosaccades of smaller amplitude and several backward saccades. In contrast, when these two groups were compared to full-term children matched for chronological age, the latter group showed significantly shorter duration of fixations, less frequent saccades and larger amplitude prosaccades. Thus, the oculomotor pattern we observed in 7-year-old children who were either preterm or reading-delayed, relative to their age-matched peers, reflected delayed development of brain areas involved in reading-related eye movements.

Children's and adults' eye movements and the extraction of number information from ambiguous and unambiguous markings

Children learn to extract number information from utterances using a variety of language-specific cues, but in some languages this information is encoded in features that display high variability in their realization. How does this affect their acquisition process? In this paper, we present an eye tracking study comparing 3.5- to 7.5-year-old children and adults' use of number information on the verb and the determiner of the subject noun phrase in Chilean Spanish, a dialect of Spanish with variable realization of plural morphology in the noun phrase (due to phonological weakening) and categorical realization of number on the verb. Our results suggest that, while adults can determine whether the subject refers to a plurality or a singleton set based on the morphology of the verb alone, even 5- to 7.5-year-old children do not and, instead, require information from the noun phrase determiner to make a decision. Children younger than 5 years, instead, cannot use number information on the verb and on the determiner to make a decision. This supports Miller and Schmitt's (2010, 2012) hypothesis that number morphology is not always mapped into syntactic and semantic features by younger children in varieties of Spanish where number is subject to variation.

Off to a good start: Early Spanish-language processing efficiency supports Spanish- and English-language outcomes at 4½ years in sequential bilinguals

Many Latino children in the U.S. speak primarily Spanish at home with few opportunities for exposure to English before entering school. For monolingual children, the strongest early predictor of later school success is oral language skill developed before kindergarten. Less is known about how early oral language skills support later learning in sequential bilingual children. A question with wide-reaching significance is whether skill in a child's first language (L1) supports later learning in a second language (L2). In this longitudinal study of sequential Spanish-English bilinguals, we assessed oral language skills in Spanish at 2 years through parent reports of vocabulary size and children's real-time language processing efficiency (Accuracy, RT) in the 'looking-while-listening' (LWL) task. At 4½ years, we assessed language outcomes in both Spanish and English using standardized tests. Reported relative exposure to each language was significantly correlated with language outcomes in Spanish and English. Within-language relations were observed between Spanish vocabulary size and processing efficiency at 2 years and later Spanish-language outcomes. Critically, across-language relations were also observed: Children with stronger Spanish-language processing efficiency at 2 years had stronger English-language skills at 4½ years, controlling for socioeconomic status and exposure to English. Children's early language processing efficiency in Spanish is associated with stronger real-time information processing skills that support maintenance of Spanish and learning in English when these children enter school. These results support the recommendation that primarily Spanish-speaking families should engage in activities that promote children's Spanish-language skills while also seeking opportunities for children to be exposed to English.

Lexical processing of nouns and verbs at 36 months of age predicts concurrent and later vocabulary and school readiness

Children's lexical processing speed at 18 to 25 months of age has been linked to concurrent and later language abilities. In the current study, we extend this finding to children aged 36 months. Children (N = 126) participated in a lexical processing task in which they viewed two static images on noun trials (e.g., an ear of corn and a hat), or two dynamic video clips on verb trials (e.g., a woman stretching and the same woman clapping), and heard an auditory prompt labeling one of them (e.g., "Where is she stretching?"). They also participated in standard assessments of language and school readiness. The results indicated that lexical processing speed (i.e., how long they required to look to the labeled image or scene) was associated with measures of concurrent receptive vocabulary, as well as receptive vocabulary and school readiness two years later, although the associations are weaker than for younger children.

Does speed of processing or vocabulary size predict later language growth in toddlers?

It is becoming increasingly clear that the way that children acquire cognitive representations depends critically on how their processing system is developing. In particular, recent studies suggest that individual differences in language processing speed play an important role in explaining the speed with which children acquire language. Inconsistencies across studies, however, mean that it is not clear whether this relationship is causal or correlational, whether it is present right across development, or whether it extends beyond word learning to affect other aspects of language learning, like syntax acquisition. To address these issues, the current study used the looking-while-listening paradigm devised by Fernald, Swingley, and Pinto (2001) to test the speed with which a large longitudinal cohort of children (the Language 0-5 Project) processed language at 19, 25, and 31 months of age, and took multiple measures of vocabulary (UK-CDI, Lincoln CDI, CDI-III) and syntax (Lincoln CDI) between 8 and 37 months of age. Processing speed correlated with vocabulary size - though this relationship changed over time, and was observed only when there was variation in how well the items used in the looking-while-listening task were known. Fast processing speed was a positive predictor of subsequent vocabulary growth, but only for children with smaller vocabularies. Faster processing speed did, however, predict faster syntactic growth across the whole sample, even when controlling for concurrent vocabulary. The results indicate a relatively direct relationship between processing speed and syntactic development, but point to a more complex interaction between processing speed, vocabulary size and subsequent vocabulary growth.

Predicting text reading skills at age 8 years in children born preterm and at term

BACKGROUND

Children born preterm are at risk for developing reading difficulties and for decrements in other cognitive skills compared to children born at term.

AIMS

To assess how domains of function, often negatively impacted by preterm birth, predict reading development in children born preterm and at term.

STUDY DESIGN

Longitudinal descriptive cohort study.

SUBJECTS

Preterm (n = 48; gestational age 22-32 weeks, 30 males) and term (n = 41, 18 males) participants were assessed at age 6 years on a battery of verbal and non-verbal cognitive skills and reassessed at age 8 using the Gray Oral Reading Tests-5. Linear regressions assessed the contributions of phonological awareness, language, executive function, and non-verbal IQ at age 6 to reading outcome at age 8.

RESULTS

Children born preterm had lower scores than children born at term on all measures (Cohen's d from 0.46 to 1.08, all p < .05). Phonological awareness and language abilities predicted reading in both groups (accounting for 19.9% and 25.0% of variance, respectively, p < .001). Birth group did not moderate the association. By contrast, the association between executive function and non-verbal intelligence and reading outcome was moderated by birth group (interaction accounted for 3.9-6.7% of variance, respectively, p < .05). Positive predictions to reading from executive function and non-verbal IQ were found only in children born preterm.

CONCLUSIONS

Non-verbal cognitive skills improved the prediction of reading outcome only in the preterm group, suggesting that reading decrements represent a component of global deficits. These findings have implications for evaluation of children born preterm at school entry and treatment of reading difficulties.

Predictors of early vocabulary growth in children born preterm and full term: A study of processing speed and medical complications

Delays in expressive vocabulary may be harbingers of long-term language difficulties. In toddlers born full term (FT), individual differences in language processing speed are associated with variation in expressive vocabulary growth. Children born preterm (PT) are at increased risk for persistent language deficits. Here, we evaluate predictors of early vocabulary growth in PT toddlers in relation to two sources of variability: language processing speed and medical complications of prematurity. Vocabulary growth from 16 to 30 months (adjusted for degree of prematurity) was modeled longitudinally using parent reports in English-speaking FT (n = 63; ≥37 weeks, ≥2495 g) and PT (n = 69; ≤32 weeks, <1800 g) children, matched on sex and socioeconomic status. Children were tested in the "looking-while-listening task" at 18 months to derive a measure of language processing speed. Each PT child was assessed for number of medical complications (13 maximum), based on medical chart reviews. PT and FT children displayed similar vocabulary trajectories; however, birth group disparities began to emerge by 30 months. PT children were slower in language processing speed than FT children. Critically, language processing speed predicted expressive vocabulary size at 30 months; interactions with birth group were not significant (all p > .20). In PT children, faster language processing speed predicted stronger outcomes regardless of number of medical complications; slower processing speed and more medical complications predicted poorer outcomes. Faster processing speed reflected favorable neuropsychological processes associated with faster expressive vocabulary growth that overrode the impact of medical complications on language outcomes in PT children.

Does early object exploration support gesture and language development in extremely preterm infants and full-term infants?

BACKGROUND

An increasing body of research on typically and atypically developing infants has shown that motor skills play an important role in language development. To date, however, the role of specific object exploration skills for early gesture and vocabulary development has not been investigated in extremely low gestational age infants (ELGA, GA < 28 weeks), who are at greater risk for motor and language delays than full-term (FT) infants.

PURPOSE

This longitudinal study examined relations between 6-month active exploratory behaviors and 12- month word comprehension, gestures and vocal production, controlling for cognitive performance and neonatal condition (ELGA vs FT).

METHODS

Forty infants, 20 ELGA and 20 FT, and their mothers participated in the study. Mother-infant play interaction was video-recorded at 6 and 12 months. Oral and manual object exploration at 6 months and spontaneous gestures and vocal production at 12 months were coded. Word comprehension was evaluated with the Italian version of the MacArthur-Bates CDI parent questionnaire at 12 months. Cognitive performance was examined with the Griffiths Mental Developmental Scales at 6 months and the Bayley-III Scales at 12 months.

RESULTS

Regression analyses showed that after accounting for cognitive performance and neonatal condition, oral exploration was related to word comprehension, and manual exploration to gestures and vocal production in the overall sample.

CONCLUSIONS

Cascading effects of specific object exploration skills on gestures and language comprehension and production in preterm infants and FT infants are discussed. Clinical implications for early assessment of and interventions involving object exploration skills, which may affect language development, are considered for the preterm population.

Speed of Language Comprehension at 18 Months Old Predicts School-Relevant Outcomes at 54 Months Old in Children Born Preterm

OBJECTIVE

Identifying which preterm (PT) children are at increased risk of language and learning differences increases opportunities for participation in interventions that improve outcomes. Speed in spoken language comprehension at early stages of language development requires information processing skills that may form the foundation for later language and school-relevant skills. In children born full-term, speed of comprehending words in an eye-tracking task at 2 years old predicted language and nonverbal cognition at 8 years old. Here, we explore the extent to which speed of language comprehension at 1.5 years old predicts both verbal and nonverbal outcomes at 4.5 years old in children born PT.

METHOD

Participants were children born PT (n = 47; ≤32 weeks gestation). Children were tested in the "looking-while-listening" task at 18 months old, adjusted for prematurity, to generate a measure of speed of language comprehension. Parent report and direct assessments of language were also administered. Children were later retested on a test battery of school-relevant skills at 4.5 years old.

RESULTS

Speed of language comprehension at 18 months old predicted significant unique variance (12%-31%) in receptive vocabulary, global language abilities, and nonverbal intelligence quotient (IQ) at 4.5 years, controlling for socioeconomic status, gestational age, and medical complications of PT birth. Speed of language comprehension remained uniquely predictive (5%-12%) when also controlling for children's language skills at 18 months old.

CONCLUSION

Individual differences in speed of spoken language comprehension may serve as a marker for neuropsychological processes that are critical for the development of school-relevant linguistic skills and nonverbal IQ in children born PT.