Gestational Mild COVID-19 Infection Associated Neonatal Hearing Loss: A Case-Control Study from North India.

COVID-19 infection during pregnancy is potentially dangerous to neonatal hearing, as it is the period of organogenesis, and associated hyperthermia may cause vascular damage, disruption of cell migration, and death of the dividing neuroblasts. To investigate the possible association between neonatal hearing loss and gestational mild COVID-19 infection. A prospective case-control study was conducted at a tertiary healthcare centre in North India from March 2020 to Oct 2022. Cases included the neonates born to COVID-19-positive mothers were subjected to hearing screening at 1, 3 and 6 months using otoacoustic emission (OAE) and automated auditory brainstem response (AABR). Similar protocol was applied to controls, i.e., neonates borne to mothers with no gestational history of COVID infection. Results were analyzed statistically. Our study reported that the statistical difference between groups A (n = 942) and B (n = 942) for gestational COVID-19 infection and neonatal hearing loss was insignificant at 1 month (p-value 0.272 for OAE and p-value 0.634 for AABR) and also insignificant at 3 and 6 months (p-value 0.679 for AABR, for both). The association between gestational mild COVID-19 infection during gestation and neonatal hearing loss is statistically insignificant at initial screening as well as sequential screenings.

Acoustic basis of context dependent brainstem encoding of speech.

The newfound context dependent brainstem encoding of speech is evidence of online regularity detection and modulation of the sub-cortical responses. We studied the influence of spectral structure of the contextual stimulus on context dependent encoding of speech at the brainstem, in an attempt to understand the acoustic basis for this effect. Fourteen normal hearing adults participated in a randomized true experimental design in whom brainstem responses were recorded. Brainstem responses for a high pass filtered /da/ in the context of syllables, that either had same or different spectral structure were compared with each other. The findings suggest that spectral structure is one of the parameters which cue the context dependent sub-cortical encoding of speech. Interestingly, the results also revealed that, brainstem can encode pitch even with negligible acoustic information below the second formant frequency.