Neural conduction abnormality in the brain stem and prevalence of the abnormality in late preterm infants with perinatal problems

Effects of neurodevelopmental risk factors on brainstem maturation in premature infants

BACKGROUND

Interpeak latencies (IPL), as measured by the auditory brainstem-evoked responses (ABR) test, represent the conduction time, and therefore the maturation of the brainstem auditory pathway. We aimed to study the effect of various risk factors for the neurodevelopmental delay on the conduction time in the auditory pathway among normal hearing premature infants, at term postmenstrual age (PMA).

METHODS

Retrospective analysis of 239 premature infants (gestational age 32.5 ± 2.1 weeks, birth weight 1827 ± 483 g). Interpeak latencies, demographic data, and risk factors were recorded.

RESULTS

Sex, PMA at ABR test, being small for gestational age (SGA), intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL), and days of invasive ventilation were found to significantly affect the IPL's in the auditory pathway in a univariate analysis. Multivariable regression analysis revealed that male sex and less advanced PMA at the examination were independent factors associated with prolonged IPL's, while bronchopulmonary dysplasia, IVH or PVL and being SGA shortened the IPL's. Non-invasive mechanical ventilation, did not affect the caudal part of the auditory pathway, despite its high noise level.

CONCLUSIONS

Among various risk factors for the neurodevelopmental delay, male sex was associated with delayed, while IVH or PVL, BPD and SGA could be associated with accelerated auditory brainstem maturation.

IMPACT

Auditory brainstem-evoked response (ABR) test, among normal hearing infants, can serve as a clinical tool to assess brainstem auditory maturation. Different neurodevelopmental risk factors could have different effects on the maturity of the auditory pathway. Male sex is significantly associated with prolonged interpeak latencies (IPL) among preterm and term infants, while intraventricular hemorrhage or periventricular leukomalacia, bronchopulmonary dysplasia, and being small for gestation age may be associated with shortened IPL The corrected age at ABR testing is of significance, among preterm and term infants.

Brainstem auditory abnormality in extremely premature babies and the impact of neonatal bronchopulmonary dysplasia

INTRODUCTION

Extremely premature babies, particularly those who have neonatal bronchopulmonary dysplasia, are at risk of brain damage and neurodevelopmental impairment. This study aimed to examine functional status of the brainstem auditory pathway in extremely premature babies and assess the impact of bronchopulmonary dysplasia on function.

MATERIAL AND METHODS

Brainstem auditory evoked response was studied at term in babies born at ≤27 weeks of gestation with or without neonatal bronchopulmonary dysplasia. The normal controls were term babies without perinatal problems.

RESULTS

Compared with the normal controls, the extremely premature babies showed an elevated response threshold, increased latencies of waves I, III and particularly V. They also showed significantly increased I-V and III-V intervals. The amplitudes of waves I and V were moderately reduced. These abnormalities were clearly more significant in those with bronchopulmonary dysplasia than those without bronchopulmonary dysplasia. A direct comparison between the two groups of extremely premature babies revealed that wave V latency, and I-V and particularly III-V intervals were significantly longer in the babies with bronchopulmonary dysplasia than those without bronchopulmonary dysplasia.

CONCLUSIONS

Extremely premature babies have functional impairment of the brainstem auditory pathway. The impairment is clearly more significant in those with bronchopulmonary dysplasia than those without bronchopulmonary dysplasia. Neonatal bronchopulmonary dysplasia and associated unfavorable conditions are major contributors to brainstem auditory impairment in extremely premature babies.

Sensory modulation in preterm children: Theoretical perspective and systematic review

BACKGROUND

Neurodevelopmental sequelae in preterm born children are generally considered to result from cerebral white matter damage and noxious effects of environmental factors in the neonatal intensive care unit (NICU). Cerebral white matter damage is associated with sensory processing problems in terms of registration, integration and modulation. However, research into sensory processing problems and, in particular, sensory modulation problems, is scarce in preterm children.

AIM

This review aims to integrate available evidence on sensory modulation problems in preterm infants and children (<37 weeks of gestation) and their association with neurocognitive and behavioral problems.

METHOD

Relevant studies were extracted from PubMed, EMBASE.com and PsycINFO following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Selection criteria included assessment of sensory modulation in preterm born children (<37 weeks of gestation) or with prematurity as a risk factor.

RESULTS

Eighteen studies were included. Results of this review support the presence of sensory modulation problems in preterm children. Although prematurity may distort various aspects of sensory modulation, the nature and severity of sensory modulation problems differ widely between studies.

CONCLUSIONS

Sensory modulation problems may play a key role in understanding neurocognitive and behavioral sequelae in preterm children. Some support is found for a dose-response relationship between both white matter brain injury and length of NICU stay and sensory modulation problems.

Auditory brainstem maturation in normal-hearing infants born preterm: a meta-analysis

AIM

Children born preterm often have neurodevelopmental problems later in life. Abnormal maturation of the auditory brainstem in the presence of normal hearing might be a marker for these problems. We conducted a meta-analysis of auditory brainstem response (ABR) latencies at term age to describe differences in auditory brainstem maturation between normal-hearing preterm and term-born infants.

METHOD

Computerized databases were searched for studies published between 1995 and 2014 that reported ABR measurements at term age in infants born preterm in a case-control design. Five peaks reflect the conduction of a neural signal along the brainstem auditory pathway. We collected I to V interpeak latency data, and III to V interpeak latency data, which refers to the more central part of the pathway.

RESULTS

Preterm-born infants' III to V interval is significantly longer compared to infants born at term (0.081ms, effect-size=0.974), which also reflects on the I to V interval. Moreover, significantly increased ABR interpeak latencies of infants born preterm are related to lower gestational age and the need for neonatal intensive care treatment.

INTERPRETATION

The delayed conduction time towards and into the auditory brainstem at term age suggests atypical maturation of the brainstem in normal-hearing infants born preterm. Both the duration of gestation and the consequences of the preterm birth (intensive care needed) negatively affect maturation of the auditory brainstem, which may influence later development.