H-reflex and motor nerve conduction studies in growth retarded newborn babies.
OBJECTIVE
To demonstrate the accelerated postnatal maturation/myelination in growth retarded babies compensating the deficit suffered by them during intrauterine life.


METHODS
We studied 16 babies within the first 3 days of birth. These included 6 full term appropriate for gestational age babies (FT AGA) and 10 full term intrauterine growth retarded (FT IUGR). A separate group of 16 babies was examined at 2 months of age. In this group 7 were FT AGA and 9 were FT IUGR at the time of birth. H-reflex latency (HRL), motor nerve conduction velocity (MNCV) and H-reflex excitability (H/M) were measured in the right lower limb. Anthropometric measurements of the babies were also recorded meticulously. All the babies were neurologically normal on clinical evaluation.


RESULTS
At birth, MNCV was significantly lower in FT IUGR babies compared to FT AGA babies. However at the age of 2 months the MNCV of both FT AGA and FT IUGR was comparable. Other parameters (HRL and H/M) in the IUGR babies were comparable with normal babies both at birth and 2 months of age. In FT IUGR babies crown-heel length and weight was significantly lower than FT AGA babies both at the time of birth and at 2 months of age.


CONCLUSIONS
The findings suggest that FT IUGR babies demonstrate accelerated postnatal peripheral neural maturation. At 2 months of age, the motor nerve conduction velocity of these growth retarded babies was comparable to that observed in normal AGA babies of similar age. This provides an insight into the functional aspect of the proven theories of decreased peripheral myelination in FT IUGR babies with subsequent rapid postnatal myelination that renders these babies neurologically equivalent to FT AGA babies despite not achieving comparable anthropometric parameters.
Dereddy
Narendra Reddy
NR
Department of Pediatrics, Unit of Neonatology, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
Muthusami
Sunil
S
Bhatia
B D
BD
Prakash
Udai
U
D004558:Electric Stimulation; D005260:Female; D005317:Fetal Growth Retardation / Q000503:physiopathology*; D005500:Follow-Up Studies; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009431:Neural Conduction / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology / Q000528:radiation effects