The Development of Cortical Responses to the Integration of Audiovisual Speech in Infancy.

In adults, the integration of audiovisual speech elicits specific higher (super-additive) or lower (sub-additive) cortical responses when compared to the responses to unisensory stimuli. Although there is evidence that the fronto-temporal network is active during perception of audiovisual speech in infancy, the development of fronto-temporal responses to audiovisual integration remains unknown. In the current study, 5-month-olds and 10-month-olds watched bimodal (audiovisual) and alternating unimodal (auditory + visual) syllables. In this context we use alternating unimodal to denote alternating auditory and visual syllables that are perceived as separate syllables by adults. Using fNIRS we measured responses over large cortical areas including the inferior frontal and superior temporal regions. We identified channels showing different responses to bimodal than alternating unimodal condition and used multivariate pattern analysis (MVPA) to decode patterns of cortical responses to bimodal (audiovisual) and alternating unimodal (auditory + visual) speech. Results showed that in both age groups integration elicits cortical responses consistent with both super- and sub-additive responses in the fronto-temporal cortex. The univariate analyses revealed that between 5 and 10 months spatial distribution of these responses becomes increasingly focal. MVPA correctly classified responses at 5 months, with key input from channels located in the inferior frontal and superior temporal channels of the right hemisphere. However, MVPA classification was not successful at 10 months, suggesting a potential cortical re-organisation of audiovisual speech perception at this age. These results show the complex and non-gradual development of the cortical responses to integration of congruent audiovisual speech in infancy.

Improving access to assessments of early motor development in local languages: polish adaptation of the Early Motor Questionnaire.

A child's motor development progresses very dynamically. It is crucial to develop freely available parent-report measures of motor development that can be easily used globally to measure motor skills and identify children in need of interventions. This paper presents the adaptation and validation of the Early Motor Questionnaire, which consists of gross motor (GM), fine motor (FM), and perception-action integration (PA) subscales, to the Polish language (EMQ-PL). Study 1 (online, cross-sectional, N = 640) assessed psychometric properties of the EMQ-PL and its value in identifying children referred to physiotherapy. Results reveal excellent psychometric properties of the EMQ-PL and differences in GM and total age-independent scores between children that were and were not referred for physiotherapy. Study 2 (in-person assessment, longitudinal, N = 100) showed high correlations of GM and total scores with Alberta Infant Motor Scale. CONCLUSION: Overall, the EMQ can be easily adapted to local languages and has the potential for use as a screening tool in global health contexts. WHAT IS KNOWN: • Parent-report questionnaires - especially those available free of charge - can potentially improve the rapid assessment of motor skills in young children worldwide. • Translation, adaptation and validation of freely available parent-report measures of motor development to local languages are important for local populations. WHAT IS NEW: • Early Motor Questionnaire can be easily adapted to local languages and has the potential for use as a screening tool in global health contexts. • The polish version of the Early Motor Questionnaire has excellent psychometric properties and highly correlates with infants' age and Alberta Infant Motor Scale scores.

Co-regulation of movements during infant feeding.

The process by which infants move from liquid feeding to caregiver-assisted spoon feeding of semi-solid food is quite a dramatic transition. In previous studies, we observed that in the weeks after the introduction to solid food, mother-infant dyads showed increased co-regulation and synchronization of their respective feeding behaviors (e.g. offering food, accepting/refusing, timing). Learning this new way of feeding and eating requires that infants coordinate their position and movements with the complementary position and movements of the caregiver. The present study augments the category-based analysis of this co-regulation by the analysis of coupling in the dyads based on automatically extracted movement data. Previously collected video data from 10 mother-infant dyads were re-analyzed for the purpose of this study. Movement trajectories of mother's hand and infant's face were obtained by applying an automatic movement detection algorithm (TLD, Kalal et al., 2012; for applications to mother-infant interactions see López Pérez et al., 2017). Coordination was assessed by the method of Diagonal Cross Recurrence Profiles (DCRP), which expresses the degree of synchronization at different time lags. Profiles for each dyad from two different occasions --with one visit in the first week of solid feeding and one approximately 4-5 weeks later-- were compared. The results showed that, on average, most synchronization occurred in the first visit at lag 0. In the second visit there was an average delay in synchronization of about 1 s, with leading behavior starting from the infant. This suggests that the coordination was initially closely synchronized and became somewhat looser over time. Possibly, infants have begun to anticipate and guide the feeding movements enacted by the mother. However, our findings underline the idiosyncratic and complex nature of co-regulation of movements during the introduction of solid food. Whereas some dyads showed signs of increased organization, others seemed to disorganize, re-organize, or showed no organization at all. Many (interacting) factors --both individual and contextual-- may be responsible for the observed differences between dyads. Further research is needed to understand why specific synchronization pathways emerge and whether and how these might relate both to later feeding and eating and to the emergent patterns of participation.

Beyond fixation durations: Recurrence quantification analysis reveals spatiotemporal dynamics of infant visual scanning.

Standard looking-duration measures in eye-tracking data provide only general quantitative indices, while details of the spatiotemporal structuring of fixation sequences are lost. To overcome this, various tools have been developed to measure the dynamics of fixations. However, these analyses are only useful when stimuli have high perceptual similarity and they require the previous definition of areas of interest (AOIs). Although these methods have been widely applied in adult studies, relatively little is known about the temporal structuring of infant gaze-foraging behaviors such as variability of scanning over time or individual scanning patterns. Thus, to shed more light on the spatiotemporal characteristics of infant fixation sequences we apply for the first time a new methodology for nonlinear time-series analysis-the recurrence quantification analysis (RQA). We present how the dynamics of infant scanning varies depending on the scene content during a "pop-out" search task. Moreover, we show how the normalization of RQA measures with average fixation durations provides a more detailed account of the dynamics of fixation sequences. Finally, we link the RQA measures of temporal dynamics of scanning with the spatial information about the stimuli using heat maps of recurrences without the need for defining a priori AOIs and present how infants' foraging strategies are driven by the image content. We conclude from our findings that the RQA methodology has potential applications in the analysis of the temporal dynamics of infant visual foraging offering advantages over existing methods.