Transient tone anomalies in very preterm infants: Association with term-equivalent brain magnetic resonance imaging and neurodevelopment at 18 months.

BACKGROUND

Very preterm (VPT) infants are at risk for neurodevelopmental impairments and early clinical findings such as transient tone anomalies (TTA) might represent potential predictive indicators.

AIMS

The aims of this study were to assess 1) the prevalence of TTA at 6 months corrected age in a population of VPT infants, 2) the association with term-equivalent age (TEA) brain MRI and 3) the neurodevelopmental outcome at 18 months corrected age.

STUDY DESIGN AND SUBJECTS

A prospective case-control cohort of 103 VPT infants (<29 weeks of gestation) was followed up at 6 months and classified into TTA+ or TTA-. TTA+ was defined by the presence of ≥2 criteria among anomalies of posture, anomalies of tone and hyperreflexia.

OUTCOME MEASURES

Conventional and diffusion-weighted MRIs at TEA were analyzed according to a semi-quantitative MRI scoring system and apparent diffusion coefficients (ADC) and fractional anisotropy (FA) were measured in frontal, occipital white matter and posterior limb of the internal capsule (PLIC). Neurodevelopment was assessed at 18 months using Bayley-II scales (Psychomotor Developmental Index: PDI; Mental Developmental Index: MDI).

RESULTS

TTA+ infants represented 29.1% of the total population. They had: 1) significantly higher ADC values in 3 regions of interest (p < 0.001), 2) significant lower FA in the PLIC (p < 0.001), and 3) significant lower PDI score (p < 0.05). No differences were observed regarding MDI scores. Interaction of TTA by cerebellum score was related to lower MDI scores.

CONCLUSIONS

In VPT infants, TTA at 6 months and/or structural brain abnormality at TEA are associated with poorer neurodevelopmental outcome at 18 months.