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Published on: April 24, 2017
Acoustic Reflex Testing in Neonatal Hearing Screening and Subsequent Audiological Evaluation
Lilian Cássia Bórnia Jacob-Corteletti1, Eliene Silva Araújo2, Josilene Luciene Duarte3
1Department of Audiology and Speech Pathology, Bauru Dental School, University of São Paulo, Brazil.
Insights
Neonates with lower birth weight and gestational age showed reduced acoustic reflex elicitation and higher thresholds, indicating a higher risk for hearing impairment. Broadband noise effectively elicited responses in all infants.
Area of Science:
- Neonatal audiology
- Otoacoustic emissions
- Hearing screening
Background:
- Neonatal hearing loss affects 1-3 per 1000 live births.
- Early detection and intervention are crucial for optimal language and cognitive development.
- Risk factors for neonatal hearing loss include low birth weight and prematurity.
Purpose of the Study:
- To evaluate acoustic reflex screening and thresholds in healthy neonates and those at risk.
- To determine the impact of birth weight and gestational age on acoustic stapedial reflex (ASR).
Main Methods:
- Assessed 18 healthy neonates and 16 at-risk neonates using transient evoked otoacoustic emissions (TEOAEs).
- Conducted acoustic reflex screening and threshold tests with pure-tone and broadband noise stimuli.
- Analyzed the influence of gestational age and birth weight on ASR.
Main Results:
- Lower gestational age and birth weight were associated with reduced ASR elicitation by pure tones, particularly at 0.5, 1, and 2 kHz.
- At-risk neonates (Group II) exhibited higher ASR thresholds and absent reflexes more frequently compared to healthy neonates (Group I).
- Broadband noise elicited responses in all neonates, while pure-tone stimuli revealed significant differences between groups at 1, 2, and 4 kHz.
Conclusions:
- Birth weight and gestational age significantly influence acoustic reflex elicitation in neonates.
- Infants with risk factors like low birth weight and prematurity are less likely to exhibit ASR and have elevated thresholds.
- ASR testing, especially with broadband noise, is valuable for neonatal hearing assessment, with pure-tone results indicating higher risk in preterm or low birth weight infants.
Purpose:
The aims of the study were to examine the acoustic reflex screening and threshold in healthy neonates and those at risk of hearing loss and to determine the effect of birth weight and gestational age on acoustic stapedial reflex (ASR).
Method:
We assessed 18 healthy neonates (Group I) and 16 with at least 1 risk factor for hearing loss (Group II); all of them passed the transient evoked otoacoustic emission test that assessed neonatal hearing. The test battery included an acoustic reflex screening with activators of 0.5, 1, 2, and 4 kHz and broadband noise and an acoustic reflex threshold test with all of them, except for the broadband noise activator.
Results:
In the evaluated neonates, the main risk factors were the gestational age at birth and a low birth weight; hence, these were further analyzed. The lower the gestational age at birth and birth weight, the less likely that an acoustic reflex would be elicited by pure-tone activators. This effect was significant at the frequencies of 0.5, 1, and 2 kHz for gestational age at birth and at the frequencies of 1 and 2 kHz for birth weight. When the broadband noise stimulus was used, a response was elicited in all neonates in both groups. When the pure-tone stimulus was used, the Group II showed the highest acoustic reflex thresholds and the highest percentage of cases with an absent ASR. The ASR threshold varied from 50 to 100 dB HL in both groups. Group II presented higher mean ASR thresholds than Group I, this difference being significant at frequencies of 1, 2, and 4 kHz.
Conclusions:
Birth weight and gestational age at birth were related to the elicitation of the acoustic reflex. Neonates with these risk factors for hearing impairment were less likely to exhibit the acoustic reflex and had higher thresholds.
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