Neurological examination of preterm infants at term equivalent age

BACKGROUNDS: We previously reported the neurological findings of the Dubowitz neonatal examination in a cohort of 157 low-risk preterms born between 25 and 33 weeks gestational age (GA) and examined at term equivalent age (TEA). Median and range of scores were wider than those found in term-born infants and preterms showed a different neurological behaviour in specific items. However, the cohort number was too small to draw any definitive conclusion about the distribution of findings. AIMS: We provide normative data from a low-risk cohort of 380 preterm infants; we also assess the findings and their relationship to motor outcome in preterms with major cranial ultrasound (US) abnormality. STUDY DESIGN: We assessed, at TEA, 380 low-risk preterms born <35 weeks gestation (range 25-34.9, median 29) with normal 2 year motor outcome and 85 preterm infants with major US abnormality. RESULTS: At TEA low-risk preterms had less flexor limb tone, poorer head control but better visual following than term-born infants. For 28/34 of the neurological items the range and median scores were similar across gestational ages. In infants with major US lesions the range and median scores differed from low-risk preterms in 20/34 items; 40% of infants developing a diplegia and 80% developing a tetraplegia had >7 items outside the 90th centile; all infants with >12 items outside the 90th centile developed a tetraplegia. CONCLUSIONS: We provide reference values for the neurological examination of low-risk preterms at TEA. In infants with major US abnormality the number of items outside the 90th centile was an indicator of outcome severity.     

Prevalence and predictors of idiopathic asymmetry in infants born preterm

Background

An idiopathic asymmetry in posture of the head is recognized as a risk factor to develop a deformational plagiocephaly (DP). In our neonatal follow-up clinic, an IA is often observed in infants born preterm at term-equivalent age (TEA).

Aims

To explore (1) the prevalence of an idiopathic asymmetry in 192 infants (gestational age ≤ 32.0 weeks) at TEA and 6 months corrected age (CA), (2) whether demographical, perinatal, and medical factors were predictors of the asymmetry, and (3) differences in motor maturation between infants with and without asymmetry.

Methods

In a retrospective study, frequencies of idiopathic asymmetry and DP, putative predictors, and Alberta Infant Motor Scale scores at 6 months CA were abstracted and analyzed with Chi², Mann–Whitney, logistic regression and T-test.

Results

The prevalence rate of a positional preference of the head at TEA was 44.8% (n = 86), 10.4% (20/192) had a DP at TEA and 13% (25/192) at 6 months CA. Positional preference, multiple birth and male gender predicted the presence of DP (p < .05, odds ratio 3.0, 3.2, and 3.1 respectively). Gross motor maturity at 6 months CA was less developed in infants with a positional preference at TEA compared to preterm norms (p = 0.01).

Conclusions

The high prevalence of a positional preference in infants born preterm at term equivalent age requires extra alertness to prevent the development of a deformational plagiocephaly, especially in boys and twins. Although, considering the lower prevalence of plagiocephaly at 6 months CA, therapists should be aware of over treating these infants.     

Prediction of developmental performance in preterm infants at two years of corrected age: contribution of the neurological assessment at term age

Background

The population of preterm infants is increasing and resources available for follow-up are limited. Early markers are needed to identify children who will show major as well as more subtle neurodevelopmental impairments. Such a challenge could be achieved with the Amiel-Tison Neurological Assessment at Term (ATNAT).

Aims

This study assesses the usefulness of the ATNAT in the prediction of developmental problems at two years of corrected age (CA) in infants born between 29 and 37 weeks of gestation.

Method

Inclusion criteria were: gestational age between 29^0/7 and 36^6/7 weeks inclusively, birth weight below 2500 g and minimal 24-hour stay in the Neonatal Intensive Care Unit of Sainte-Justine Hospital. A sample of 147 was prospectively recruited and assessed at two ages: at term with the ATNAT and at 24 months CA with Bayley Scales of Infant Development-II.

Results

No major impairment such as cerebral palsy and no neurosensory impairment were observed. Developmental delay defined by an index < 70 on the mental or psychomotor scale was reported respectively in 6.2% and 5.4% of the cohort. Significant differences in mental, psychomotor and behavioral performances were found according to neurological status. Neurological status was the only variable to enter the predictive model for psychomotor and behavioral indexes. Gender and neurological status remained in the predictive model for mental performance.

Conclusion

This study supports the inclusion of the ATNAT among the eligibility criteria for systematic neurodevelopmental surveillance as it allows early identification of infants at higher risk of low developmental performances at 24 months CA.     

Predicting neurosensory disabilities at two years of age in a national cohort of extremely premature infants

Background

Extreme prematurity carries a high risk of neurosensory disability.

Aims

Examine which information obtained pre-, peri- and postnatally may be predictive of neurosensory disabilities at 2 years of age.

Study design

Prospective observational study of all infants born in Norway in 1999 and 2000 with gestational age (GA) 22-27 completed weeks or birth weight (BW) of 500-999 g.

Outcome measures

Incidence of neurosensory disabilities.

Results

Of 373 surviving children, 30 (8%) had major neurosensory disabilities (26 CP, 6 blind, 3 deaf), and a further 46 (12%) had minor visual or hearing disabilities. The rate of major neurosensory disabilities was 19 of 99 (19%) for children with GA 23-25 vs. 8 of 189 (4%) for GA 26-27 weeks (p < 0.001). In a multivariable model, only morbidities detected in the neonatal intensive care unit (NICU) were associated with major neurosensory disabilities; adjusted odds ratios (95% confidence intervals) were 68.6 (18.7, 252.2) for major abnormalities on cerebral ultrasound, 6.8 (1.7, 27.4) for retinopathy of prematurity (ROP) grade > 2, 3.2 (1.0, 9.7) for ROP grade 1-2, 6.5 (1.9, 22.3) for prolonged use (≥ 21 days) of steroid treatment for lung disease and 3.1 (1.0, 9.4) for clinical chorioamnionitis. The visual outcome was strongly related to the degree of ROP (p < 0.001), and all who had a normal hearing screen in the NICU had normal hearing at 2 years.

Conclusion

NICU morbidities, rather than GA or intrauterine growth are the significant predictors of major neurosensory disabilities among extreme prematurity surviving to discharge from the NICU.