Speech-Encoding Deficits in Neonates Born Large-for-Gestational Age as Revealed With the Envelope Frequency-Following Response

Abstract

Objectives:The present envelope frequency-following response (FFR ENV ) study aimed at characterizing the neural encoding of the fundamental frequency of speech sounds in neonates born at the higher end of the birth weight continuum (>90th percentile), known as large-for-gestational age (LGA).Design: Twenty-five LGA newborns were recruited from the maternity unit of Sant Joan de Déu Barcelona Children's Hospital and paired by age and sex with 25 babies born adequate-for-gestational age (AGA), all from healthy mothers and normal pregnancies. FFR ENV s were elicited to the/da/ syllable and recorded while the baby was sleeping in its cradle after a successful universal hearing screening. Neural encoding of the stimulus' envelope of the fundamental frequency (F 0ENV ) was characterized through the FFR ENV spectral amplitude. Relationships between electrophysiological parameters and maternal/neonatal variables that may condition neonatal neurodevelopment were assessed, including pregestational body mass index (BMI), maternal gestational weight gain and neonatal BMI. Results:LGA newborns showed smaller spectral amplitudes at the F 0ENV compared to the AGA group. Significant negative correlations were found between neonatal BMI and the spectral amplitude at the F 0ENV . Conclusions:Our results indicate that in spite of having a healthy pregnancy, LGA neonates' central auditory system is impaired in encoding a fundamental aspect of the speech sounds, namely their fundamental frequency. The negative correlation between the neonates' BMI and FFR ENV indicates that this impaired encoding is independent of the pregnant woman BMI and weight gain during pregnancy, supporting the role of the neonatal BMI. We suggest that the higher adipose tissue observed in the LGA group may impair, via proinflammatory products, the fine-grained central auditory system microstructure required for the neural encoding of the fundamental frequency of speech sounds.

Exposure to bilingual or monolingual maternal speech during pregnancy affects the neurophysiological encoding of speech sounds in neonates differently

“…Neural lag served as an indicator of the neural transmission delay within the auditory system, and was assessed to estimate the time passed from cochlear stimulus reception to the onset of neural phase-locking (Arenillas-Alcón et al, 2021; Arenillas-Alcón et al, 2023; Jeng et al, 2010; Liu et al, 2015; Ribas-Prats et al, 2019, 2023; Ribas-Prats et al, 2021). To calculate the neural lag, a cross-correlation analysis was computed between the auditory stimulus and the neural response.…”

“…The RMS of the pre-stimulus period was employed as a measure of the general magnitude of neural activity over time, and to dismiss electrophysiological disparities in the pre-stimulus region (Arenillas-Alcón et al, 2023; Liu et al, 2015; Ribas-Prats et al, 2019, 2023; Ribas-Prats et al, 2021; White-Schwoch et al, 2015). This measure was computed by squaring each data point within the pre-stimulus region of the neural response (from −40 to 0 ms), calculating the mean of the squared values and subsequently obtaining the square root of the resulting average.…”

“…Additionally, as performed in previous research from our laboratory (Arenillas-Alcón et al, 2021; Arenillas-Alcón et al, 2023; Ribas-Prats et al, 2019, 2023; Ribas-Prats et al, 2021), both groups of newborns received a standard click-evoked auditory brainstem response (ABR) test to ensure the integrity of the auditory pathway. A click-stimulus, with a duration of 100 µs, was employed during the test, presented at a rate of 19.30 Hz with an intensity of 60 dB sound pressure level (SPL) until a total of 4000 artifact-free repetitions were collected.…”

“…Spectral amplitude at F 0 (113 Hz) was used as a quantitative measure of the neural phase-locking strength at the specific frequency of interest (Arenillas-Alcón et al, 2021; Arenillas-Alcón et al, 2023; Ribas-Prats et al, 2019, 2023; Ribas-Prats et al, 2021; White-Schwoch et al, 2015). It was computed by applying a fast Fourier transform (FFT; Cooley & Tukey, 1965) to obtain the frequency spectrum of the neural response during the steady pitch section of the stimulus (10-160 ms), and then calculating the average amplitude within a ±5 Hz window centered around the peak of the stimulus F 0 .…”

Longitudinal trajectories of the neural encoding mechanisms of speech-sound features during the first year of life

“…After a successful universal hearing screening test, the ABR and subsequently the FFR were recorded at the hospital room while the newborns were sleeping in their crib, following the same protocol used in previous studies (see Arenillas-Alcón et al, 2021, 2023; Ribas-Prats et al, 2019, 2022, 2023a, 2023b; for a review see Gorina-Careta el al., 2022). Recording was interrupted to any sign of discomfort or sleep disruption and it was resumed when the newborn was asleep again.…”