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40-Hz steady-state responses in newborns and in children
M Maurizi1, G Almadori, G Paludetti
1Institute of Otorhinolaryngology, Catholic University of the Sacred Heart, Rome, Italy.
Insights
The 40-Hz steady-state responses (SSR) are less reliable in newborns than in older children for assessing hearing thresholds. Response stability and accuracy improve significantly with age.
Area of Science:
- Auditory Neuroscience
- Developmental Audiology
Background:
- The 40-Hz steady-state response (SSR) is an auditory evoked potential used to assess hearing.
- Understanding developmental changes in auditory processing is crucial for early identification of hearing impairments.
Purpose of the Study:
- To investigate the characteristics of 40-Hz SSR in newborns and young children.
- To compare the reliability and stability of 40-Hz SSR between age groups.
Main Methods:
- Auditory evoked potentials, specifically 40-Hz SSR, were recorded in 32 full-term newborns and 10 children (5-8 years old).
- Stimuli consisted of 500-Hz tone bursts.
- Thresholds, latencies, amplitudes, and test-retest reliability were analyzed.
Main Results:
- The 40-Hz SSR threshold was higher in newborns (50 dB nHL) compared to older children (30 dB nHL).
- Response latencies decreased, and amplitudes increased with age.
- 40-Hz SSR showed improved stability, replicability, and P1-N1 wave occurrence in older children.
Conclusions:
- 40-Hz SSR are challenging to obtain and less reliable for low-frequency hearing assessment in newborns.
- Auditory processing, as reflected by 40-Hz SSR, matures significantly from infancy to childhood.
- Increased stability and reliability with age suggest overlapping electrophysiological and behavioral thresholds for low-frequency stimuli in older children.
Abstract:
The authors investigated the 40-Hz steady-state responses (SSR) in 32 full-term newborns and in 10 normal children (5-8 years old), using 500-Hz tone bursts. The 40-Hz SSR threshold is located at about 50 and 30 dB nHL in newborns and older children, respectively. The latencies of both P1 and N1 waves decreased significantly with age, while the amplitudes increased. No significant latency and amplitude intersex differences have been observed. Moreover, with age, the 40-Hz SSR became more stable, their test-retest replicability improved, and P1-N1 wave occurrence increased. The authors finally discuss the possible underlying mechanisms of these findings and conclude that the 40-Hz SSR are difficult to obtain and are scarcely reliable in defining the low-frequency threshold in newborns. The stability and reliability of the responses increase with age, and the electrophysiological and behavioral thresholds to low-frequency stimuli tend to overlap.