Word recognition and phonological representation in very low birth weight preterms

BACKGROUND

Several studies have shown impaired neurocognitive development in infants born very preterm. Language is one of the areas that may be affected. Early lexical development measurements have revealed possible delays associated with low gestational age, but no studies have analyzed lexical processing using real-time measures in this at-risk population.

AIMS

To explore the effects of preterm birth on the robustness of phonological representations and lexical processing speed.

SUBJECTS AND METHODS

Eighteen two-year-old VLBW healthy preterms (≤32weeks of gestation; ≤1500g) and a matched group of at term infants, equivalent in age, gender, SES, linguistic environment and expressive lexicon were compared in a 'looking-while-listening' task, using correctly pronounced and mispronounced known words involving a vowel change. Percentage of target fixation, longest look duration, shift rate and orientation latency measures were used to analyze possible between-group differences in phonological representation and familiar word recognition processes.

RESULTS

Based on the percentage of fixation time measure both groups succeeded at word recognition and responded similarly to mispronunciations. However, preterms significantly differed from full-terms in processing speed measures, showing longer look duration, lower shift rate and slower orientation latencies to target from distracter.

CONCLUSIONS

Preterm birth negatively affects lexical processing speed. Birth weight and gestational age are two critical variables in these results. Slower language processing in preterms can compromise the acquisition of more complex lexical and grammatical representations later in development and may underlie poor language outcomes frequently observed in children born very prematurely.

[Algorithm for an etiological classification of prematurity]

The etiology of preterm birth is difficult to classify. It is usually divided into three clinical types according to its clinical presentation: medically indicated; caused by ruptured membranes; and spontaneous or idiopathic. However, this classification is controversial, imprecise and can result in multiple interpretations when applied.

OBJECTIVE

To design an etiologically based classification of preterm birth, and to design a system to easily assign each case during the perinatal period.

METHODS

Review of literature, qualitative analysis using consensus methods through nominal group technique, and quantitative analysis of a pilot study using a first version of the algorithm.

RESULTS

A classification is made to establish a general division between the "primary cause" and "associated causes" of preterm birth, that allows remote causes or risk factors to be included. The primary cause includes seven categories: inflammatory (ruptured membranes and related); vascular (intrauterine growth restriction and related); maternal-local; maternal-systemic; fetal pathology; fetal distress; idiopathic. The medically indicated preterm birth is defined as a previous or independent category and so is compatible with the other, previously mentioned causes . An algorithm was designed to make it easier to classify the primary cause of preterm birth using a flowchart.

CONCLUSIONS

A pragmatic classification of preterm birth is proposed that may help to achieve better precision and agreement between clinicians.

Rehospitalization because of respiratory syncytial virus infection in premature infants younger than 33 weeks of gestation: a prospective study. IRIS Study Group

OBJECTIVE

To collect data on hospitalization for respiratory syncytial virus (RSV) infections and presumptive risk factors for rehospitalization among premature infants in Spain.

DESIGN

Observational, prospective, longitudinal, multicenter study.

SETTING

Fourteen Spanish neonatal units with an annual birth cohort of 57,000 infants.

PATIENTS

All children (n = 680) born < or =32 weeks of gestational age between April 1, 1998, and March 31, 1999, and discharged from the hospital before March 31, 1999, were included in the study. A total of 96 were excluded because of administration of prophylactic treatment (n = 55) or were lost to follow-up (n = 41). Five children died during the study period, but death was related to RSV in only 1 case.

METHODS AND MAIN OUTCOME MEASURES

Neonatal and demographic data were recorded at the initial visit. Infants were prospectively followed at monthly intervals up to March 31, 1999. In patients rehospitalized for respiratory disorders, further data about RSV status and morbidity were collected. A comparison was made between children rehospitalized for RSV infection and those who were not. The influence of factors on the probability of rehospitalization for RSV infection was assessed by logistic regression analysis.

RESULTS

Of the 584 evaluable patients 118 (20.2%) were rehospitalized for respiratory disease during the study period. The causative pathogen was identified in 89 (75.4%) hospital admissions. Of these 59 (66.3%) were a result of RSV infection in 53 children; 6 were reinfections. In a logistic regression model significant independent prognostic variables included: lower risk of RSV hospitalization with increase gestational age [odds ratio (OR), 0.85; 95% confidence interval (CI), 0.72 to 0.99; P < 0.047]; higher risk with chronic lung disease (OR = 3.1; 95% CI 1.22 to 7.91; P < 0.016); and living with school age siblings (OR = 1.86; 95% CI 1.01 to 3.4; P < 0.048).

CONCLUSION

This large descriptive study has enabled us to define the influence of specific risk factors that increase the risk of rehospitalization for RSV infection in preterm infants. Such studies help to define the appropriate role of available prophylactic interventions and establish treatment guidelines.

[Validation of perinatal causes of death in death certificates]

OBJECTIVE

The objective of this study was to assess the validity of perinatal causes of death in death certificates and the influence of some variables related to perinatal mortality.

PATIENTS AND METHODS

All perinatal deaths having occurred in Barcelona in 1994 and reported in death certificates were included. Additional sources of information were certificates of abortions and also other documents such as autopsy reports and medical records, that served as references to determine the most reliable or standard cause of death (SBC) The SBC was determined by a group of experts. The validity was assessed by comparing the cause of death as stated in the death certificate (BC) and the SBC, calculating the general agreement, the detection rate (DR) or sensitivity and the confirmation rate (CR) or positive predictive value. The chi-square test was used to compare proportions.

RESULTS

In 166 (91.2%) of the 182 cases, the BC and SBC were assigned to the same group of the International Classification of Diseases. For congenital defects, the DR was 85.7 (95% CI: 75.1-96.3) and the CR was 81.8 (95% CI: 70.4-93.2). For problems in the perinatal period the DR was 95.6 (95% CI: 92.1-99.1) and the CR was 94.9 (95% CI: 91.2-98.6). Both were considered reliable causes. These rates were similar for the different categories of other variables (birth weight, gestational age, vital status, sex, hospital of birth, autopsy and mother's age). Nevertheless, in the study of detailed causes (3 digits of the International Classification of Diseases) the general agreement was much lower (40.1%). Except for the congenital defects of the nervous system, the remaining causes of death had a low validity.

CONCLUSIONS

This study shows the low validity of detailed causes of perinatal death reported in death certificates. It is necessary to improve the completion and coding of death certificates following the WHO recommendations.

Schinzel-Giedion syndrome: report of two sibs

We report on two further cases, a sister and a brother, with Schinzel-Giedion syndrome. Both presented the following manifestations: "coarse face" with midface retraction, agenesis of corpus callosum, bilateral hydronephrosis, and typical skeletal anomalies. Patient 1 had a malignant sacrococcygeal teratoma. This is the third case of malignancy in this syndrome. Patient 2 died shortly after birth.

[Neurological development of very low birth weight infants (<1,501 gr) at two ears of age]

The aim of this study is to analyse different aspects of the psychomotor development, during the first two years of the life, of 56 very low birth weight newborns (less of 1.501 g) that had completed a follow-up program. Of the results we have got, the most important are the following: 4 observations (7%) presented severe sequelae motor disability in a tetraparesis with sensorial defects in 3 of them and behavior disturbance (psychosis) with visual defect in the rest. Three observations (5.3%) presented moderate sequelae: all of them with motor disability (hemi- or tetraparesis) and cognitive deficiency. Me have to point out that in the two groups described above, the pathological signs were detected before the age of 6 months. Nine observations (16%) presented mild sequelae dominating language delayed (7% of whole sample) and transient abnormalities in 7 of them (12.5%). In the subgroup of small for gestational age newborns (21 observations), 28.5% presented mild sequelae, 14% transient abnormalities and no one presented severe or moderate sequelae. Although a long term follow-up is necessary in order to detect learning, cognitive, or behavior disturbances, that can just become evident later, we think that the attention of the deviations of the normality during the two first years of the life, would warn about possible future disturbances.