Term Postmenstrual Age Research Articles

Gastroesophageal Reflux in the Preterm Neonate

After completing this article, readers should be able to: 1. Describe the epidemiology and pathophysiology of gastroesophageal reflux (GER) in preterm neonates. 2. Delineate the associations of GER with apnea, chronic lung disease, behavior, and growth of preterm infants. 3. Review the investigations used to evaluate GER in preterm infants. 4. Describe nonpharmacologic and pharmacologic therapies for GER. Gastroesophageal reflux (GER) is a normal physiologic event occurring across the age spectrum. It may contribute to a variety of disorders, including esophagitis, feeding problems, and airway disease in all age groups. (1) A large number of symptoms and signs have been purported to be caused by GER despite a lack of data showing a clear association between a specific symptom and GER. In preterm infants, empiric therapy often is administered using agents of unproven efficacy and safety to treat symptoms that likely are unrelated to GER. In a survey on management practices for GER in preterm infants, common treatment strategies included positioning (98%) and slopes (96%), histamine 2 (H 2) receptor antagonists (100%), feed thickeners (98%), antacids (96%), prokinetics (79%), proton pump inhibitors (PPIs) (65%), and dopamine receptor antagonists (53%). (2)(3) The safety, efficacy, and appropriate dosing recommendations for most medical therapies remain uncertain in neonates. In this review, we attempt to summarize the current literature regarding physiology, pathophysiology, and diagnostic and management strategies for GER pertinent to the neonate, with an emphasis on the preterm infant. GER describes the retrograde movement of stomach contents (air or feeding, liquid or semisolid, acid or alkaline, enzymes or bile salts) into the esophagus. GER disease (GERD) occurs when GER causes symptoms or signs such as pain, poor weight gain, esophagitis, hematemesis, and airway symptoms, including apnea, aspiration, recurrent pneumonia, chronic lung disease (CLD), or large airway inflammation. However, any of these symptoms or signs …

Altered pathways for auditory discrimination and recognition memory in preterm infants

Preterm infants are at increased risk for cognitive disorders, including impairments in recognition memory. This study evaluated the effects of extreme prematurity on the neural pathway for auditory recognition memory using event‐related potentials (ERPs), a neurophysiological technique widely used in cognitive neuroscience. ERPs were recorded at term postmenstrual age in 35 preterm infants born at less than 32 weeks’gestation (22 males, 13 females; mean birthweight ([BW] 1154g, SD 374g) with normal brain ultrasounds, compared with 40 healthy, term newborns (1 to 3 days of age; 20 males, 20 females; BW 3672g, SD 420g). Because infants must be able to detect and discriminate sounds before recognizing them, two paradigms were used to assess these functions. The first evaluated the detection and discrimination of speech sounds. The second tested recognition of the mother's voice compared with a stranger's. Results showed significantly different patterns of speech sound discrimination in preterm infants compared with term infants. No evidence of maternal voice recognition was elicited from the preterm infants. No specific patterns of auditory detection or discrimination were associated with patterns of recognition memory, suggesting that the function of multiple neural pathways may have been altered in this group of preterm infants. These results provide a functional corroboration of magnetic resonance imaging studies showing effects of prematurity on early brain development, even among preterm infants with normal cranial ultrasonography.

Altered pathways for auditory discrimination and recognition memory in preterm infants

Preterm infants are at increased risk for cognitive disorders, including impairments in recognition memory. This study evaluated the effects of extreme prematurity on the neural pathway for auditory recognition memory using event-related potentials (ERPs), a neurophysiological technique widely used in cognitive neuroscience. ERPs were recorded at term postmenstrual age in 35 preterm infants born at less than 32 weeks' gestation (22 males, 13 females; mean birthweight ([BW] 1154g, SD 374g) with normal brain ultrasounds, compared with 40 healthy, term newborns (1 to 3 days of age; 20 males, 20 females; BW 3672g, SD 420g). Because infants must be able to detect and discriminate sounds before recognizing them, two paradigms were used to assess these functions. The first evaluated the detection and discrimination of speech sounds. The second tested recognition of the mother's voice compared with a stranger's. Results showed significantly different patterns of speech sound discrimination in preterm infants compared with term infants. No evidence of maternal voice recognition was elicited from the preterm infants. No specific patterns of auditory detection or discrimination were associated with patterns of recognition memory, suggesting that the function of multiple neural pathways may have been altered in this group of preterm infants. These results provide a functional corroboration of magnetic resonance imaging studies showing effects of prematurity on early brain development, even among preterm infants with normal cranial ultrasonography.

Bioelectric brain maturation in fullterm infants and in healthy and pathological preterm infants at term post-menstrual age

At the same post-menstrual age (39–41 weeks), EEG maturation assessed according to the Nolte and Haas method (Nolte, R. and Haas, H.G. (1978) Dev. Med. Child Neurol., 20, 167–182) was studied in 16 fullterm infants (FT), 17 healthy preterm infants (HP) and 18 pathological preterm infants (PP) affected by brain lesions (haemorrhage and/or leucomalacia). There were no significant differences in respect to EEG maturational codes, EEG types or bioelectrical age between the FT and HP groups. The preterm infants affected by brain lesions presented higher percentages of younger EEG codes (i.e. 36 weeks) in State 1 and a higher number of fluctuations between one maturation code and another in both State 1 and State 2, with respect to the HP group. Also, although the PP infants with young EEG codes did not present serious background EEG abnormalities, they did reveal minor EEG abnormalities, such as excessive asynchrony of the ‘tracé alternant', lack of frontal sharp transients and monomorphic TA ‘bouffees’ with little activity at 2–6 c/s. However, no relationship between young EEG codes and onset-offset or duration of the states was found: young codes were often randomly distributed in successive State 1-State 2 epochs, regardless of groupings. Bioelectric age appropriate to the post-menstrual age precedes a normal development or only minor handicap at 24 months, while EEG immaturity of more than 2 weeks corresponds to later major handicaps. The prognostic value of EEG immaturity of between 1.1 and 2 weeks is uncertain.