Hearing impairment in ventilator-dependent infants and children

Auditory impairment in infants with neonatal chronic lung disease is alleviated after term

AIM

Very premature infants with neonatal chronic lung disease (CLD) have been reported to have major auditory impairment at term, and we examined the outcomes in 30 infants after term age.

METHODS

Brainstem auditory evoked response (BAER) was recorded at a postconceptional age of 46-61 weeks in 13 CLD cases and 14 controls from China and 17 CLD cases and 22 controls from the UK.

RESULTS

The BAER threshold in the CLD infants was slightly higher. Clicks at the normal hearing level (60 dB) showed no significant differences between the cases and controls in the latencies of BAER waves I, III and V and the I-V interval. However, the CLD infants demonstrated marginal shortening in the I-III interval and a marginal increase in the III-V interval. The amplitudes of BAER waves in the CLD infants were all slightly smaller than the controls. At 70 and 40 dB normal hearing level, the BAER findings were similar to those obtained at 60 dB normal hearing level, with only small variations.

CONCLUSION

There were minor BAER abnormalities in the CLD infants, suggesting minor auditory impairment. The auditory impairment previously detected at the term date was later alleviated.

Reliability of hearing screening in high-risk neonates: Comparative study of otoacoustic emission, automated and conventional auditory brainstem response

OBJECTIVE

To compare the diagnostic reliability of automated transient evoked otoacoustic emissions (a-TEOAE), automated auditory brainstem response (a-ABR) and conventional brainstem auditory evoked potential (BAEP/ABR) for identification of hearing loss in high-risk neonates.

METHODS

Two hundred and six neonatal intensive care unit (NICU) admitted neonates were tested pre-discharge. Follow-up included a-TEOAE in all children, repetition of a-ABR or BAEP if failed in NICU. Sensitivity and specificity were compared and correlated with auditory risk factors.

RESULTS

BAEP had the highest sensitivity (100%) and specificity (90.8%), a-ABR the lowest (88.9% and 70.6%). A statistically significant difference in risk factors for temporary hearing loss was observed between normal and false positive a-TEOAE and BAEP, but not a-ABR outcome. Differences in specificity between a-ABR and a-TEOAE explain the pattern of "absent a-ABR/present a-TEOAE" in 13.8% of ears.

CONCLUSIONS

The BAEP appears the more reliable test for hearing screening of high-risk neonates because of highest sensitivity and specificity and should be used to confirm the diagnosis of "auditory neuropathy" in high-risk neonates. The reliability of a-ABR devices in critically ill neonates needs further investigation.

SIGNIFICANCE

This is, to our knowledge, the first attempt to compare the diagnostic reliability of a-TEOAE, a-ABR and BAEP in high-risk neonates.

Hearing and language in preschool very low birthweight children

To get more insight into preschool language and hearing in high-risk very low birthweight (VLBW) children, we conducted a prospective study in a cohort of 79 children. The prevalence of language impairment and hearing loss at age 3-4 years, their relationship to each other as well as to perinatal conditions, neurodevelopmental outcome and the home environment are described. Mild hearing loss was found in 26%, moderate hearing loss in 13% and severe hearing loss in 3% of the children. None of the children was deaf. Abnormal tympanometry was found in 57% of the children. Hearing loss at age 4 years was related to a less optimal neonatal condition and was not related to the obstetrical condition or to neonatal cerebral ultrasound findings. Language impairment was found in 21% of the children at age 3.6 years. Receptive and expressive language was not related to perinatal conditions. There was no relation between the language assessments and the audiological assessments. Cognition and the home environment of the child were the only independent variables in the prediction of language in preschool VLBW children.

Auditory Brain Stem Responses Recorded With Uncushioned Earphones

Although the cushion is essential to accurate pure-tone audiometry with conventional earphones, it may interfere with the auditory brain stem response (ABR) testing of small infants because of its size and the risk of ear canal collapse. To determine the consequences of ABR testing with an uncushioned earphone, adults were tested with and without the cushion, and probe-tube sound measurements were made. Although removing the cushion results in substantial signal attenuation below 1 kHz, there is little effect on the click-elicited ABR.