Exploratory study of the relationship of fat-free mass to speed of brain processing in preterm infants.
BACKGROUND
Preterm infants are at risk for long-term neurodevelopmental impairment as a function of postnatal nutritional status. Despite adequate neonatal weight gain, preterm infants have altered body composition, with lower fat-free mass (FFM) and higher adiposity at term corrected gestational age (CGA) than their term counterparts. The relationship between postnatal body composition and speed of brain processing in preterm infants is unknown.


METHODS
Anthropometric measurements and body composition testing via air displacement plethysmography were performed on 16 appropriate-for-gestational age (GA) preterm (mean GA: 30.4 ± 2.8 wk) infants at term and 4 mo CGA. Infant visual pathway development was assessed at 4 mo CGA using pattern-reversal visual evoked potential (VEP); P100 (positive peak) latency was used to index neuronal speed of processing.


RESULTS
Increased FFM at discharge (P = 0.02) and 4 mo CGA (P = 0.006) was associated with shorter latencies to the P100 peak. P100 latency was not related to total body weight, fat mass, or body fat percentage.


CONCLUSIONS
FFM reflects protein accretion and indexes growth of organs, including the brain. The association of shorter VEP latency (i.e., faster neuronal processing) with higher FFM (i.e., better protein status) may be attributed to the positive effects of protein status on neuronal growth and differentiation.
Department of Pediatrics, University of Minnesota, Minneapolis, Minnesota.
Katie M
KM
Pfister
Heather L
HL
Gray
Neely C
NC
Miller
Ellen W
EW
Demerath
Michael K
MK
Georgieff
Sara E
SE
Ramel
D000886:Anthropometry; D001823:Body Composition / Q000502:physiology*; D015992:Body Mass Index; D001921:Brain / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007234:Infant, Premature / Q000502:physiology*; D010991:Plethysmography; D014795:Visual Pathways / Q000502:physiology*