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Development of flexor spastic signs in preterm infants
Insights
The Rossolimo and Mendel-Bechterew reflexes in preterm infants change with conceptional age (CA). Specific reflex patterns between 34-38 weeks CA indicate normal motor development, while later deviations suggest potential upper motor neuron lesions.
Area of Science:
- Neonatal Neurology
- Developmental Pediatrics
- Neuroscience
Background:
- The development of lower-limb reflexes in preterm infants is crucial for assessing neurological maturation.
- The Rossolimo and Mendel-Bechterew reflexes are commonly used to evaluate the developing nervous system in neonates.
Purpose of the Study:
- To characterize the typical changes in Rossolimo and Mendel-Bechterew lower-limb reflexes in preterm infants.
- To establish normative reflex patterns associated with normal motor development up to the first postnatal trimester.
- To identify reflex abnormalities that may indicate delayed motor development or upper motor neuron lesions.
Main Methods:
- Repeated examination of Rossolimo and Mendel-Bechterew lower-limb reflexes in 55 preterm infants (birthweight 800-2000g, gestational age 25-33 weeks).
- Assessment of reflex patterns in relation to conceptional age (CA) from birth up to the first postnatal trimester.
Main Results:
- An abduction-extension reflex pattern was observed up to 34 weeks CA.
- A shift towards a flexor spasticity response occurred between 34 and 36 weeks CA, persisting in some infants into the first postnatal trimester.
- This flexor response around 34-38 weeks CA is considered a sign of normal developmental maturation.
Conclusions:
- The observed changes in lower-limb reflexes correlate with normal neurodevelopmental maturation in preterm infants.
- An extension-abduction response after 38 weeks CA or a flexor response persisting after the first postnatal trimester may signal delayed motor development.
- These reflex patterns can serve as valuable indicators for identifying potential upper motor neuron lesions in preterm infants.
Abstract:
Fifty-five preterm infants with birthweights between 800 and 2000g and gestational ages between 25 and 33 weeks were repeatedly examined for the Rossolimo and Mendel-Bechterew lower-limb reflexes. Up to 34 weeks conceptional age (CA) an abduction-extension pattern was characteristic. Between 34 and 36 weeks CA the response changed to one implying flexor spasticity, which in some cases lasted throughout the first postnatal trimester. It is thought that this response occurring around 34 to 38 weeks CA is a sign of normal developmental maturation. On the other hand, an extension-abduction response after 38 weeks CA and a flexor response after the first trimester is indicative of delayed motor development and might suggest an upper motor neuron lesion.