Auditory brainstem response in neonates: influence of gender and weight/gestational age ratio

Auditory Pathway Maturation in Full-term Small for Gestational Age Children: A Systematic Review with Meta-analysis

Introduction  Factors of intrauterine growth restriction have been responsible for the births of full-term babies small for their gestational age (SGA). Scientific evidence points that this restriction can cause changes in the neural maturation process. Objectives  To analyze the absolute latencies and interpeak intervals of brainstem auditory evoked potential waves in full-term and SGA children to investigate whether there are changes of neural maturation in this population. Data Synthesis  The search for articles that reported the assessment of brainstem auditory evoked potential in SGA newborns compared with a control, appropriate for their gestational age, both born full-term, for the entire period available in the database research until October 31, 2021 was performed based on the MEDLINE/PubMed Central and on the Latin America and the Caribbean Health Sciences Literature and Virtual Health Library electronic databases. A total of 311 studies were found in the database research. Out of this total, 10 studies were included in the review, 5 of which were eligible for the meta-analysis, involving a total of 473 participants of both genders, with 193 participants belonging to the study group and 280 to the control group. Differences between the groups were only observed in the absolute latency of wave V (95% confidence interval [CI]: 0.02-0.15; p  < 0.01). Conclusion  The SGA condition is responsible for the appearance of brainstem neural conduction dysfunction measured by the brainstem auditory evoked potentials, probably by the maturation process of the auditory pathway of this population.

Auditory brainstem response with click and CE-Chirp® Level Specific stimuli in hearing infants

INTRODUCTION

The assessment of the integrity of the neural responses with ABR, aims to assist in the differential diagnosis of retrocochlear alterations. The gold standard stimulus for this assessment is Click. However, the CE-Chirp® Level Specific was developed to optimize the triggering of neural responses.

OBJECTIVE

to compare neural responses obtained with CE-Chirp® LS stimulus to those obtained with Clicks at 70 dB nHL in hearing infants, in order to analyze advantages in using CE-Chirp® LS.

METHODS

Eighteen infants with normal hearing were evaluated with Eclipse EP25 ABR System. Clicks and CE-Chirp® LS stimuli were presented using ER-3A insert earphones at 70 dB nHL, rate 45.1/s, and alternating polarity. A 30 Hz high-pass and 1500 Hz low-pass filter was applied, and ±40 μV artifact rejection level. Absolute latency of waves I, III and V and their interpeak intervals I-III, III-V and I-V were measured, as well as interaural difference for wave V and interpeak I-V, and wave V amplitude.

RESULTS

Although 18 infants were included in the study, it was possible to collect data only in 30 ears for Click stimulus, and 33 ears for CE-Chirp® LS, according to exclusion criteria. It was possible to record waves I, III, and V for both stimuli at 70 dB nHL in all normal-hearing infants. CE-Chirp® LS stimulus evoked a higher wave V amplitude than Click (p < 0.001). Wave I absolute latency was statistically different between stimuli (p < 0.001), being delayed for CE-Chirp® LS. Wave III absolute latency was statistically different between stimuli only for the right ear (p = 0.021), and wave V absolute latency was similar in both stimuli (p = 0.210). Interpeak intervals I-III and I-V were statistically different between stimuli (p < 0.001), being reduced for CE-Chirp® LS. Interpeak interval III-V was different between the stimuli only for right ears (p = 0.006). There was no difference between stimuli for interaural difference wave V (p = 1.33) and interaural difference interpeak I-V (p = 0.409).

CONCLUSION

It is possible to use CE-Chirp® LS stimulus in order to analyze neural synchrony in infants at 70 dB nHL, since better morphology waveforms were observed, and higher wave V amplitudes could be recorded. We suggest that new studies with infants with neurological disabilities and various hearing status, to observe how CE-Chirp® LS stimulus evokes neural responses in these conditions.

Auditory Brainstem Evoked Response Patterns in the Neonatal Intensive Care Unit

OBJECTIVE

Delayed maturation of auditory brainstem pathway in neonates admitted to the neonatal intensive care unit (NICU) may lead to misdiagnosis of children with normal peripheral hearing and inappropriate use of amplification devices. The aim of this study is to determine the pattern of auditory brain stem response in neonates admitted to the NICU for proper hearing assessment in this high-risk population.

STUDY DESIGN

This prospective study was conducted on 1,469 infants who were admitted to the NICU, of which 1,423 had one or more risk factors for permanent congenital hearing loss and were screened with automated auditory brain stem response (AABR). A total of 60 infants were referred for diagnostic ABR analysis after failure on AABR screening. The control group comprised 60 well-baby nursery neonates with no risk factors for PCHL.

RESULTS

Mean values of absolute latencies of waves III and V; interpeak latencies I-III, III-V, and I-V; amplitude of waves I, and V; and I/V amplitude ratio at 90 dBnHL measured for the right and left ears at 1 and 3 months of age show significant difference in NICU neonates compared with controls (p < 0.05). All the diagnostic ABR measurements significantly improved at the age of 3 months (p < 0.001) except wave I absolute latency of both groups (p > 0.05). Significant correlations were found between ABR readings at the age of 1 and 3 months and the gestational age of the NICU neonates (p < 0.05).

CONCLUSION

Diagnostic ABR findings in NICU neonates suggested delayed maturation of the auditory brainstem pathway with a great impact of gestational age on this maturation. Auditory maturational changes were observed at 3 months of age of patient and control groups.

Cry features of healthy neonates who passed their newborn hearing screening vs. those who did not

OBJECTIVES

Temporal and fundamental frequency (fo) variations in infant cries provide critical insights into the maturity of vocal control and hearing performances. Earlier research has examined the use of vocalisation properties (in addition to hearing tests) to identify infants at risk of hearing impairment. The aim of this study was to determine whether such an approach could be suitable for neonates.

METHODS

To investigate this, we recruited 74 healthy neonates within their first week of life as our participants, assigning them to either a group that passed the ABR-based NHS (PG, N = 36) or a group that did not, but were diagnosed as normally hearing in follow-up check at 3 months of life, a so-called false-positive group (NPG, N = 36). Spontaneously uttered cries (N = 2330) were recorded and analysed quantitatively. The duration, minimum, maximum and mean fo, as well as two variability measures (fo range, fo sigma), were calculated for each cry utterance, averaged for individual neonates, and compared between the groups.

RESULTS

A multiple analysis of variance (MANOVA) revealed no significant effects. This confirms that cry features reflecting vocal control do not differ between healthy neonates with normal hearing, irrespective of the outcome of their initial NHS.

CONCLUSIONS

Healthy neonates who do not pass the NHS but are normal hearing in the follow-up (false positive cases) have the same cry properties as those with normal hearing who do. This is an essential prerequisite to justify the research strategy of incorporating vocal analysis into NHS to complement ABR measures in identifying hearing-impaired newborns.

Cortical auditory evoked potential in assessment of neonates: a study about minimum level of responses in term and preterm newborns

INTRODUCTION

The study of the threshold level of cortical auditory response in adults has been investigated in previous studies. Due to maturational issues, little is known about these responses in neonates. Technological advances with automatic analysis devices now allow investigation in specific populations. Thus, new studies are needed to establish the feasibility of using this auditory potential to identify the lowest levels of responses in children.

OBJECTIVE

Verify and compare latency and amplitude in 80dBnNA and the minimum level of cortical auditory response in term and preterm neonates.

METHODS

A cross-sectional, comparative study involving 59 neonates, 35 full-term births and 24 preterm births, with positive results in the Neonatal Hearing Screening. The Hearlab system was used to investigate the P1i auditory potential with tone burst stimulus at frequencies of 500, 1000, 2000 and 4000Hz. The minimum response level search ranged from 80 to 0dBNA and was detected automatically. The results were compared between groups, evaluating the latency and amplitude in 80dBNA and the minimum level of cortical auditory response.

RESULTS

The mean values obtained for the minimum level of cortical auditory response in term group were 26±8.81; 26.14±6.97; 29±7.65 and 29.43±7.04dBNA and for preterm neonates of 31.96±10.41; 34.13±11.34; 33.64±11.03 and 37.73±11.92dBNA, for the frequencies of 500, 1000, 2000 and 4000Hz, respectively. There was a difference between groups for the latency of P1i at 4000Hz and the minimum response levels at 500, 1000 and 4000Hz, with higher values for preterm infants.

CONCLUSION

It was possible to obtain latency and amplitude values at 80dBnNA and the minimum level of cortical response in term and preterm newborns, with different results between groups, with higher values in those born preterm.

Auditory brainstem response in very preterm, moderately preterm and late preterm infants

BACKGROUND

Auditory brainstem response across preterm infants help in understanding difference if any in auditory maturation.

OBJECTIVE

To analyze and compare absolute and interpeak latencies of ABR in very preterm, moderate preterm and late preterm infants at term age.

METHOD

ABR traces were obtained from 148 ears of preterm infants (52 of very preterm, 44 of moderately preterm & 52 of late preterm) at term age. ABR was recorded with 11.1/s clicks at different intensity levels.

RESULTS

Absolute latencies of peak I, III, V and interpeak latencies of peak I-V, I-III and III-V were analyzed and compared between three preterm groups. One way ANOVA was used to compare ABR parameters between three groups of preterm infants and also to compare ABR parameters across various gestation ages. There were no overall differences in absolute latencies, interpeak latencies and amplitude of ABR between preterm groups and across various gestation ages (P>0.05). Pearson correlation was used to find the correlation between gestation age and ABR parameters. However, no correlation was found. ABRs were similar among preterm groups at term age which reflects that the brainstem maturation is similar among preterm groups.

CONCLUSION

Gestational age at birth does not seem to influence absolute and interpeak latencies of ABR at term age. In preterm neonates, the findings lead to suggest that maturation of auditory pathway occurs in a similar manner in preterm infants regardless of gestational age at birth. We conclude that preterm birth alone as a risk factor does not appear to have any marked effect on the development of ABR at term age.

Transient evoked otoacoustic emissions and auditory brainstem response in infants with perinatal asphyxia

OBJECTIVE

The objective of this study was to verify the effects of perinatal asphyxia on different parts of the auditory system.

METHODS

This was a non-concurrent cohort study conducted on a fixed population in a tertiary public hospital. Participants included 181 infants born at term who underwent the transient evoked otoacoustic emission test as a part of a neonatal hearing screening program, with a "pass" result in both ears, and by auditory brainstem response testing. The infants were divided into 3 groups: G1, 20 infants who had perinatal asphyxia; G2, 111 infants with an Apgar score lower than 4 in the first minute and/or lower than 6 in the fifth minute (called "low Apgar" at birth); and G3, 50 infants with first- and fifth-minute Apgar scores ≥7.

RESULTS

The signal-to-noise ratio of transient evoked otoacoustic emissions were greater in G3 compared with G1 and G2 at 4 kHz frequency for males. An increased latency of waves I and III in the auditory brainstem response of male infants in G1 was observed.

CONCLUSION

This study demonstrated that alterations occurred in both the cochlear and the neural components in male infants who had perinatal asphyxia.