Neurodevelopment and asymmetry of auditory-related responses to repetitive syllabic stimuli in preterm neonates based on frequency-domain analysis

Farveh Daneshvarfard (1, 2) , Hamid Abrishami Moghaddam (1, 2) , Ghislaine Dehaene-Lambertz (3) , Guy Kongolo (4, 1) , Fabrice Wallois (1, 4) , Mahdi Mahmoudzadeh (1, 4)

1 GRAMFC - Groupe de Recherche sur l'Analyse Multimodale de la Fonction Cérébrale - UMR INSERM_S 1105
2 KNTU - K. N. Toosi University of Technology
3 UNICOG-U992 - Neuroimagerie cognitive - Psychologie cognitive expérimentale
4 CHU Amiens-Picardie

Sensory development of the human brain begins prenatally, allowing cortical auditory responses to be recorded at an early age in preterm infants. Despite several studies focusing on the temporal characteristics of preterm infants' cortical responses, few have been conducted on frequency analysis of these responses. In this study, we performed frequency and coherence analysis of preterm infants' auditory responses to series of syllables and also investigated the functional brain asymmetry of preterm infants for the detection of the regularity of auditory stimuli. Cortical auditory evoked potentials (CAEPs) were recorded in 16 preterm infants with a mean recording age of 31.48 weeks gestational age (29.57-34.14 wGA) in response to a repetitive syllabic stimulus. Peak amplitudes of the frequency response at the target frequency and the first harmonic, as well as the phase coherence (PC) at the target frequency were extracted as age-dependent variables. A functional asymmetry coefficient was defined as a lateralization index for the amplitude of the target frequency at each electrode site. While the findings revealed a significant positive correlation between the mean amplitude at the target frequency vs. age (R2 = 0.263, p = 0.042), no significant correlation was observed for age-related changes of the mean amplitude at the first harmonic. A significant correlation was also observed between the mean PC and age (R2 = 0.318, p = 0.023). A right hemisphere lateralization over many channels was also generally observed. The results demonstrate that rightward lateralization for slow rate modulation, previously observed in adults, children and newborns, appears to be in place at a very young age, even in preterm infants. Development of the auditory system is an intricate process beginning early in gestation 1. Major structures of the ear, including the cochlea, develop between 23 and 25 weeks gestational age (wGA) 1-3 and the capacity of the foetus to perceive and react to auditory inputs, related to brainstem network activation, emerges around 26 weeks of foetal life 4. After 28 wGA, the thalamocortical auditory system is sufficiently mature to perceive complex sounds and discriminate between different speech phonemes 5-9 , corresponding to the beginning of language and speech development 10. A critical period for neurosensory development of the auditory system starts around 25 wGA. During this period, the hair cells of the cochlea, the axons of the auditory nerve and the neurons of the temporal lobe in the auditory cortex are tuned to receive signals of specific frequencies and intensities 11. Cortical brain development can also be studied in preterm infants, who, as a result of intensive care, can survive when born after 28 wGA, and even 23 wGA 5. Arousal behaviour confirms that the auditory system is

Domaines: Sciences cognitives; Neurosciences

Farveh Daneshvarfard, Hamid Abrishami Moghaddam, Ghislaine Dehaene-Lambertz, Guy Kongolo, Fabrice Wallois, et al.. Neurodevelopment and asymmetry of auditory-related responses to repetitive syllabic stimuli in preterm neonates based on frequency-domain analysis. Scientific Reports, 2019, 9 (1), ⟨10.1038/s41598-019-47064-0⟩. ⟨hal-02324707⟩