Outcomes and limitations of hospital-based newborn hearing screening

Is intrauterine exposure to COVID-19 infection a risk factor for infant hearing loss?

Purpose

To determine whether exposure to intrauterine COVID-19 infection causes congenital or late-onset hearing loss in infants.

Material and method

The hearing screening results of infants born in a tertiary hospital between March 2020 and April 2022 with and without a history of intrauterine exposure to COVID-19 infection (36 infants each) were retrospectively analyzed within one month after birth in all infants and additionally at six months after intrauterine COVID-19 infection exposure in the study group. The automated auditory brainstem response (AABR) test was used for the hearing evaluation.

Results

The polymerase chain reaction test was negative in study group exposed to intrauterine COVID-19 infection. The number of infants admitted to the intensive care unit (ICU), and the length of ICU stay were significantly higher in this group (p < 0.01). Six infants (16.6 %) in the study group failed the first AABR test bilaterally, but five of these infants passed the second AABR test. A bilateral severe sensorineural hearing loss was detected in one infant (2.77 %). All the infants in the study group underwent the AABR test again at six months, and all infants, except this infant, passed the test. In the control group, five infants (13.88 %) failed the first AABR test bilaterally, but they all passed the second test.

Conclusions

Exposure to COVID-19 infection in the intrauterine period does not cause congenital or late-onset hearing loss (within six months) in infants; therefore, gestational COVID-19 infection is not a risk factor for infant hearing loss.

Results of a 10-year hearing screening using automated auditory brainstem response in newborns: The two-step AABR method

OBJECTIVES

Approximately 1-6 in every 1000 children are born with hearing loss. An automated auditory brainstem response (AABR) test is essential for screening newborns for abnormal hearing. At the tertiary hospital, we have been using a two-step AABR protocol for newborn hearing assessment since 2005. This study aimed to report the 10-year hearing screening results of newborns at the institution, and prove the efficacy of the two-step AABR protocol.

METHODS

From August 2005 to January 2015, 3059 newborns were screened through AABR testing using the MASTER ABaer system. The first screening test was performed after the first 24 h of life. If a newborn was referred, the test was performed within 1 month after discharge from the hospital. The results were regarded as pass when the point optimized variance ratio was >3.5, using a stimulus level of 35 dB HL. When newborns were referred for the second AABR, they received follow-up tests including tympanometry, ABR, auditory steady-state response, and otoacoustic emission within 3 months.

RESULTS

A total of 3059 newborns underwent newborn hearing screening tests over a period of 10 years. One hundred and twenty (3.9%) newborns were referred with the initial AABR, and 104 (3.4%) were referred with a subsequent AABR. Of the newborns, 42 (1.37%) were confirmed to have a bilateral hearing impairment.

CONCLUSIONS

It is known that the referral rate for the AABR test is 3-4%, as recommended by the Joint Committee on Infant Hearing. Our data showed a referral rate of 3.4%. The two-step AABR test has been useful for screening hearing loss in newborns at tertiary hospital.

Newborn screening in the developing countries

PURPOSE OF REVIEW

We review newborn screening (NBS) publications from the developing countries to identify global progress in improving child health.

RECENT FINDINGS

Many developing countries do not yet have national NBS. As infant mortality rates decline, NBS gains in public health priority. Local incidence and outcome data are used to persuade health officials to include screening in priority health spending. Congenital hypothyroidism is the most cost-effective screened condition in most countries. In sub-Saharan Africa, India and some parts of Asia, screening for hemoglobinopathies and glucose-6-dehydrogenase deficiency are also important. Expanded screening for metabolic conditions is most needed in areas of high consanguinity. Screening for hearing disorders and critical congenital heart defects is increasing globally. The largest birth cohorts are India and China, but only China has successful NBS. Reports from completed government research projects in India support initiation of NBS.

SUMMARY

Government activities around NBS are increasing in India and there is increased emphasis on pilot programs for sickle cell NBS in sub-Saharan Africa. Genetic counseling training in Asia and Africa is increasing and will be helpful as part of NBS. To build successful screening programs, partnerships among health professionals, parents, policy makers and industry stakeholders are essential.