Development of flexor spastic signs in preterm infants.

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.