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Muscle Activity during Passive and Active Movements in Preterm and Full-Term Infants
Irina Y Dolinskaya1,2, Irina A Solopova1, Dmitry S Zhvansky1
1Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow 127994, Russia.
Insights
Muscle tone development in preterm infants was studied using passive stretching and shortening responses. Early months showed altered responses, suggesting sensorimotor network changes in preterm infants.
Area of Science:
- Developmental neuroscience
- Motor control
- Infant physiology
Background:
- Muscle tone is crucial for movement and development.
- Preterm infants may exhibit distinct muscular development patterns compared to full-term infants.
- Early muscle reactions offer insights into sensorimotor network maturation.
Purpose of the Study:
- To evaluate early muscle tone manifestations in preterm infants.
- To compare muscle responses to passive stretching (StR) and shortening (ShR) in preterm vs. full-term infants.
- To investigate age-related changes in muscle tone during the first year of life.
Main Methods:
- Measured muscle responses (StR and ShR) in upper and lower limbs of preterm infants (0-12 months corrected age).
- Compared findings with data from full-term infants.
- Assessed spontaneous muscle activity during limb movements in a subgroup.
Main Results:
- Frequent StR and ShR observed in both preterm and full-term infants.
- Responses noted in non-primary muscles during passive movements.
- Age-related reduction in sensorimotor responses suggests decreasing excitability and developing muscle tone.
- Preterm infants showed alterations in early months, possibly due to sensorimotor network excitability changes.
Conclusions:
- Early muscle reactions provide insights into muscle tone development.
- Preterm infants exhibit distinct temporal patterns in sensorimotor responses.
- Findings highlight the dynamic nature of sensorimotor network maturation in the first year of life.
Abstract:
Manifestation of muscle reactions at an early developmental stage may reflect the processes underlying the generation of appropriate muscle tone, which is also an integral part of all movements. In preterm infants, some aspects of muscular development may occur differently than in infants born at term. Here we evaluated early manifestations of muscle tone by measuring muscle responses to passive stretching (StR) and shortening (ShR) in both upper and lower limbs in preterm infants (at the corrected age from 0 weeks to 12 months), and compared them to those reported in our previous study on full-term infants. In a subgroup of participants, we also assessed spontaneous muscle activity during episodes of relatively large limb movements. The results showed very frequent StR and ShR, and also responses in muscles not being primarily stretched/shortened, in both preterm and full-term infants. A reduction of sensorimotor responses to muscle lengthening and shortening with age suggests a reduction in excitability and/or the acquisition of functionally appropriate muscle tone during the first year of life. The alterations of responses during passive and active movements in preterm infants were primarily seen in the early months, perhaps reflecting temporal changes in the excitability of the sensorimotor networks.
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