The effect of peri-intraventricular hemorrhage on the auditory pathway of infants
Introduction
Intracranial hemorrhage is the major neurological pathology in newborns. Its most common manifestation is the peri-intraventricular hemorrhage (PIVH), followed by subdural, subarachnoid and cerebellar hemorrhage, which are less frequent [1].
PIVH is almost exclusively in preterm infants, especially those weighing below 1500 g at birth and with gestational age below 32 weeks, who are particularly more vulnerable to ischemic and hemorrhagic processes in the neonatal period, and which is closely related to a multifactor lesion of the germinative matrix [[2], [3], [4]].
Its diagnosis is basically performed through ultrasound of the skull still in the first days of life [5]. PIVH is classified according to the degree of severity from I to IV [6]. Grade I occurs when subependymal hemorrhage is restricted to the germinative matrix, in grade II there is intraventricular hemorrhage without ventricular dilatation, in grade III there is ventricular dilatation and in grade IV there is periventricular hemorrhagic infarction [7,8]. Grades III and IV are considered determinants for a poor prognosis [5].
However, the literature reports that those infants with grades between I and II may also present neurological abnormality, delayed in cognitive development and hearing impairment when compared with preterm infants and normal ultrasound [5].
Studies show that 7.4% of infants with PIVH present some degree of hearing impairment [9], this occurrence can be justified due to the fact that PIVH causes the impairment of the germinative matrix, a highly vascularized region located between the caudate nucleus and thalamus, from which glial cells and neurons responsible for myelination and cortical and subcortical development arise. Thus, PIVH can compromise the development and functioning of several structures, including the auditory, which shows the importance of early audiological assessment in these individuals [10].
In the neonatal population, electroacoustic and electrophysiological exams, such as the transient-evoked otoacoustic emission (TEOAE) and brainstem auditory evoked potential (BAEP) are the most common technique for hearing screening. The first examination allows to verify, in detail, the functioning of the outer hair cells of the cochlea, the peripheral portion of the auditory system, and the second one predominantly examines the auditory pathway at the brainstem level [11].
Therefore, the hearing assessment in newborns with PIVH is necessary for a better understanding of the manifestations of this condition on the auditory pathway, which consequently may impair the development of hearing and language skills [[12], [13], [14]].
Thus, the aim of this study was to verify the effect of PIVH on the auditory pathway of preterm infants.
Section snippets
Method
This study was approved by the Research Ethics Committee of the institution (process number 2.206.522). It was a single non-concurrent cohort study, conducted from March to October 2017.
Results
The inclusion criteria were met by 44 infants with an average age of 3 months in infants with PIVH and 2,6 months in infants without PIVH (p = 0.284), the sample characterization is shown in Table 1.
As the study comprised preterm infants, the association of risk indicators for hearing loss was observed: Apgar score below 4 in the first minute and/or below 6 in the fifth minute, ICU stay, weight at birth below 1500 g and use of ototoxic medication. However, there was no significant correlation
Discussion
PIVH can lead to serious neurological and sensory sequelae such as: cerebral palsy, visual and auditory impairments, mental retardation, acute intracranial hyperten-sion, hypoxic-ischemic brain injury, posthemorrhagic hydrocephalus and periventricular hemorrhagic infarction [17]. The lower the gestational period and the birth weight, the more frequent the PIVH, due to the immaturity of the central nervous system. Between the 26th and 32 nd weeks of gestation, the period of great proliferation
Conclusion
This study demonstrated changes in auditory structures at the level of the lower brainstem in infants who had PIVH regardless of the degree.
Conflicts of interest
The authors report no conflicts of interest.
Acknowledgements
We thank the children and their guardians for participating in the research.
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