EEG Alterations in Preterm Infants With Thyroid Dysfunction
Condition: Transient Hypothyroxinemia of Prematurity
MeSH terms: Premature Birth
Study type: Observational

Summary: 
      The aim of this study is to investigate differences in electroencephalography (EEG) evolution
      between preterm infants with and without transient hypothyroxinemia of prematurity (THOP) in
      order to find differences in the interburst interval and the background pattern and in the
      maturation of the sleep-wake cycle.
    

Detailed description: 
      1. Definition of THOP The determination of thyroid hormones (TH) are assay-specific and
           related to the infants' gestational age (GA) and moment of determination. Immediately
           after birth, there will be a surge of TH, subsequently followed by a decrease to basal
           levels. Therefore, it is difficult to obtain reference values.

           The investigators plan to set out specific reference values for the preterm patient
           population, based on the TH laboratory results of cord blood, performed in the clinical
           laboratory of UZ Leuven and available over the last 4 years. The results will be linked
           to the gestational age. Dependent whether the data distribution is normal or not, the
           investigators are planning to use standard deviations or percentiles to classify
           patients.

        2. EEG findings In this retrospective study, quantitative EEG- sleep behavior at (near)
           term age (GA 36-44 weeks) in preterm infants born <28 weeks GA, will be analyzed (n =
           87).

      EEGs were taken in the framework of the Resilience study and hereby, parental informed
      consent was already obtained.

      TH function is assessed in preterm infants ≤ 34 weeks as part of the clinical care protocol.
      No additional blood samples were taken.

      Quantitative EEG measures will be compared between the preterm infants with THOP (circulating
      thyroxine levels< P10) and without THOP. Logisitic regression will be performed to determine
      the effect of thyroid function as well as other clinical and demographic variables, on
      functional brain development at term equivalent age. These results will also be linked to
      long-term neurodevelopment outcome.

      In a subgroup of these preterm patients (n=42) sequential EEGs, recorded during their stay at
      the neonatal intensive care unit, are available. These EEGs will be analyzed in a fully
      automatic way to assess functional EEG- brain maturation.

      In this way, the investigators want to investigate whether deviations of normal preterm
      EEG-brain maturation can be discerned in preterm neonates with THOP and without THOP.

      In preterm infants with GA < 32 weeks, developmental follow up data are available at the
      corrected age of 9 months and 2 years (Follow up Convention). The investigators will use
      these results and link them to the EEG findings and THOP data.
    

Intervention name(s): EEG
Intervention type(s): Diagnostic Test
Observational model: Cohort
Time perspective: Retrospective
Sampling method: Probability Sample
Study population: 
        Preterm infants who had EEG recordings in the framework of the Resilience study and
        gestational age < 28 weeks.
      
Keywords: EEG