Caracterização eletrofisiológica da audição em prematuros nascidos pequenos para a idade gestacional

Hearing Assessment of Neonates at Risk for Hearing Loss at a Hearing Health High Complexity Service: An Electrophysiological Assessment

Introduction  Hearing is the main sensory access in the first years of life. Therefore, early detection and intervention of hearing impairment must begin before the first year of age.

Objective  To analyze the results of the electrophysiological hearing assessment of children at risk for hearing loss as part of the newborn hearing screening (NHS).

Methods  This is a cross-sectional study held at a hearing health public service clinic located in Brazil, with 104 babies at risks factors for hearing loss referred by public hospitals. A questionnaire was applied to parents, and the auditory brainstem response (ABR) test was held, identifying those with alterations in the results. The outcome of the NHS was also analyzed regarding risk factor, gestational age and gender.

Results  Among the 104 subjects, most of them were male (53.85%), and the main risk factor found was the admission to the neonatal intensive care unit (NICU) for a period longer than 5 days (50.93%). Eighty-five (81.73%) subjects were screened by NHS at the maternity and 40% of them failed the test. Through the ABR test, 6 (5.77%) infants evidenced sensorineural hearing loss, 4 of them being diagnosed at 4 months, and 2 at 6 months of age; all of them failed the NHS and had family history and admission at NICU for over 5 days as the most prevalent hearing risks; in addition, family members of all children perceived their hearing impairment.

Conclusion  Advances could be observed regarding the age of the diagnosis after the implementation of the NHS held at the analyzed public service clinic.

Effects of prematurity on language acquisition and auditory maturation: a systematic review

Purpose

To verify which damages prematurity causes to hearing and language.

Research strategies

We used the decriptors language/linguagem, hearing/audição, prematurity/prematuridade in databases LILACS, MEDLINE, Cochrane Library and Scielo.

Selection criteria

randomized controlled trials, non-randomized intervention studies and descriptive studies (cross-sectional, cohort, case-control projects).

Data analysis

The articles were assessed independently by two authors according to the selection criteria. Twenty-six studies were selected, of which seven were published in Brazil and 19 in international literature.

Results

Nineteen studies comparing full-term and preterm infants. Two of the studies made comparisons between premature infants small for gestational age and appropriate for gestational age. In four studies, the sample consisted of children with extreme prematurity, while other studies have been conducted in children with severe and moderate prematurity. To assess hearing, these studies used otoacoustic emissions, brainstem evoked potentials, tympanometry, auditory steady-state response and visual reinforcement audiometry. For language assessment, most of the articles used the Bayley Scale of Infant and Toddler Development. Most studies reviewed observed that prematurity is directly or indirectly related to the acquisition of auditory and language abilities early in life.

Conclusion

Thus, it could be seen that prematurity, as well as aspects related to it (gestational age, low weight at birth and complications at birth), affect maturation of the central auditory pathway and may cause negative effects on language acquisition.

Auditory pathway maturational study in small for gestational age preterm infants

PURPOSE

To follow up the maturation of the auditory pathway in preterm infants small for gestational age (SGA), through the study of absolute and interpeak latencies of auditory brainstem response (ABR) in the first six months of age.

METHODS

This multicentric prospective cross-sectional and longitudinal study assessed 76 newborn infants, 35 SGA and 41 appropriate for gestational age (AGA), born between 33 and 36 weeks in the first evaluation. The ABR was carried out in three moments (neonatal period, three months and six months). Twenty-nine SGA and 33 AGA (62 infants), between 51 and 54 weeks (corrected age), returned for the second evaluation. In the third evaluation, 49 infants (23 SGA and 26 AGA), with age range from 63 to 65 weeks (corrected age), were assessed. The bilateral presence of Transient Evoked Otoacoustic Emissions and normal tympanogram were inclusion criteria.

RESULTS

It was found interaural symmetry in both groups. The comparison between the two groups throughout the three periods studied showed no significant differences in the ABR parameters, except for the latencies of wave III in the period between three and six months. As for the maturation with tone burst 0.5 and 1 kHz, it was found that the groups did not differ.

CONCLUSION

The findings suggest that, in the premature infants, the maturational process of the auditory pathway occurs in a similar rate for SGA and AGA. These results also suggest that prematurity is a more relevant factor for the maturation of the auditory pathway than birth weight.