Related Experiment Videos
Screening for auditory dysfunction in high risk neonates
Insights
Brainstem auditory evoked response (BAER) screening effectively identifies infants at risk for hearing loss. Infants with BAER thresholds above 40 dBHL at term equivalent age require follow-up to detect moderate to profound hearing deficits.
Area of Science:
- Neonatal audiology
- Neurophysiology
- Developmental pediatrics
Background:
- Hearing impairment is a significant concern in preterm infants.
- Early detection of auditory deficits is crucial for timely intervention and developmental outcomes.
- Brainstem auditory evoked response (BAER) is a non-invasive electrophysiological test used to assess auditory pathway function.
Purpose of the Study:
- To determine the efficacy of BAER in identifying hearing deficits in preterm and term infants.
- To establish optimal timing for auditory screening using BAER in at-risk infant populations.
- To correlate BAER thresholds with behavioral audiological assessments at later ages.
Main Methods:
- BAER thresholds were recorded in 117 preterm and 71 term infants at various post-menstrual ages (PMAs).
- Thresholds were assessed at discharge and term equivalent age, with follow-up testing conducted.
- Infants with elevated BAER thresholds underwent further behavioral audiological testing.
Main Results:
- Infants born before 31 weeks PMA had BAER thresholds ≥ 50 dBHL.
- The majority of preterm and term infants tested at term equivalent age had BAER thresholds ≤ 30 dBHL.
- 67% of infants with BAER thresholds ≥ 40 dBHL at discharge/term equivalent age were later confirmed to have moderate to profound hearing loss.
Conclusions:
- BAER screening is effective for identifying preterm infants at risk of hearing impairment.
- Auditory screening using BAER is recommended at hospital discharge or term equivalent age.
- Infants with persistent elevated BAER thresholds (≥ 40 dBHL) require further audiological evaluation and potential habilitative support.
Abstract:
Brainstem auditory evoked responses were recorded in 117 pre-term and 71 full-term infants from the general population of infants born at a referral obstetric unit. The threshold intensity required to evoke a reliable BAER was determined at different post-menstrual ages (PMAs) and in many cases at follow-up clinics. The BAER thresholds for 12 infants born and tested at less than 31 wk PMA were all greater than or equal to 50 dBHL. Sixty-two low-gestational-age infants who were tested between 31 and 36 wk PMA had BAER thresholds between less than or equal to 30 dBHL and greater than or equal to 80 dBHL. The majority of pre-term and term infants tested at term equivalent age had BAER thresholds less than or equal to 30 dBHL. Longitudinal studies also indicated that BAER thresholds can decline rapidly during the pre-term period. Follow-up studies showed that those pre-term and term infants with BAER thresholds less than or equal to 30 dBHL had normal auditory thresholds as determined using conventional behavioural testing at 4 or more months of age. Of those infants with BAER thresholds greater than or equal to 40 dBHL at the time of discharge or at term equivalent age, 67% (n = 16) were confirmed later as having a moderate to profound hearing deficit. The remaining 8 infants in this group had had BAER thresholds at term of 40 or 50 dBHL and had normal BAER and behavioural thresholds at follow-up. The cross-sectional and longitudinal data indicate that the majority of low-gestational-age infants who are at risk of hearing deficit achieve BAER thresholds less than or equal to 30 dBHL by term equivalent age. We recommend that auditory screening of infants in this group is best performed at the time of discharge from hospital or at term equivalent age, whichever is the later. Those infants with thresholds greater than or equal to 40 dBHL at that time should be encouraged to attend follow-up testing and, if high thresholds persist, they should then be referred on for behavioural testing and assessment for habilitative support.