Related Experiment Videos
The maturation of the central auditory conduction in preterm infants until three months post term. V. The auditory
Insights
Auditory cortical evoked responses (ACRs) develop significantly from 25 weeks conceptional age (CA) to 50-52 weeks CA in preterm infants. These responses are crucial for assessing auditory development and the central auditory system in premature infants.
Area of Science:
- Neuroscience
- Developmental Biology
- Audiology
Background:
- Auditory cortical evoked responses (ACRs) provide insights into auditory system maturation.
- Understanding ACR development in preterm infants is essential for early detection of auditory processing issues.
Purpose of the Study:
- To characterize the developmental trajectory of ACRs in preterm infants.
- To investigate the relationship between conceptional age (CA) and ACR components.
- To explore topographic differences in ACRs and their implications for auditory processing.
Main Methods:
- ACRs were recorded in 65 preterm infants at multiple time points.
- Infants were grouped by gestational age (GA) and recordings were analyzed across 8 CA levels.
- ACRs were analyzed for middle latency (MLR) and slow late components, examining latency, amplitude, and detectability.
Main Results:
- ACRs first appear around 25 weeks CA, progressing through premature, transitional, and mature stages by 50-52 weeks CA.
- Component detectability generally increased with CA, reaching ~80% for N2p and N2.
- Waveforms, latency, and amplitude were age-dependent, with significant topographic differences between vertex and central temporal derivations.
Conclusions:
- ACRs demonstrate a clear developmental pattern in preterm infants, maturing significantly by 50-52 weeks CA.
- The findings support distinct generation sites for ACR components and highlight age-dependent changes.
- ACRs are valuable tools for developmental studies of central audition and clinical assessment of the auditory system in preterm infants.
Abstract:
Auditory cortical evoked responses (ACRs) were recorded in 65 preterm infants, at least on 3 occasions in 48 of them. The infants were divided into 5 groups according to their gestational age (GA). The recording sessions were performed at 8 conceptional age (CA) levels, defined as the gestational age added to the chronological age. The last recordings were obtained at 50-52 weeks CA. The ACRs were analyzed for the primary complex containing middle latency components (MLR) and the secondary complex, containing the slow late components. The ACR records first appear at about 25 weeks CA, initiating the premature stage followed by a transitional stage around term date and the gradual development into the mature stage, achieved at 50-52 weeks CA. The detectability rate of the various components generally increased with increasing conceptional age, for some of the components, especially N2p and N2, this rate achieved a value of about 80%. The degree of prematurity did not influence appreciably the development of the ACR. The waveforms, and to a lesser extent the latency and amplitude values, are strongly age dependent. Remarkable topographic differences between the ACR parameter latency and more importantly amplitude values are found between the derivations from the vertex and the central temporal areas, supporting the theory of different generation sites for the ACR components. The premature and mature ACR appeared relatively insensitive to changes in the states of vigilance. The ACR in premature infants are useful in developmental studies with respect to the central audition in premature infants and might contribute in the clinical assessment on the quality of the premature central auditory system.