Article

The severity of myelomeningocele (MMC) stems both from a loss of
neurons due to neural tube defect and a loss of function in viable neurons due to
reduced movement experience during the first year after birth. In young infants
with MMC, the challenge is to reinforce excitability and voluntary control of all
available neurons. Muscle vibration paired with voluntary movement may increase
motoneuron excitability and contribute to improvements in neural organization,
responsiveness, and control. OBJECTIVES: This study examined whether infants with
or without MMC respond to vibration by altering their step or stance behavior
when supported upright on a treadmill. DESIGN: This was a cross-sectional study.
METHODS: Twenty-four 2- to 10-month-old infants, 12 with typical development (TD)
and 12 with MMC (lumbar and sacral lesions), were tested. Infants were supported
upright with their feet in contact with a stationary or moving treadmill during
30-second trials. Rhythmic alternating vibrations were applied to the right and
left rectus femoris muscles, the lateral gastrocnemius muscle, or the sole of the
foot. Two cameras and behavior coding were used to determine step count, step
type, and motor response to vibration onset. RESULTS: Step count decreased and
swing duration increased in infants with TD during vibration of the sole of the
foot on a moving treadmill (FT-M trials). Across all groups the percentage of
single steps increased during vibration of the lateral gastrocnemius muscle on a
moving treadmill. Infants with MMC and younger infants with TD responded to onset
of vibration with leg straightening during rectus femoris muscle stimulation and
by stepping during FT-M trials more often than older infants with TD.
CONCLUSIONS: Vibration seems a viable option for increasing motor responsiveness
in infants with MMC. Follow-up studies are needed to identify optimal methods of
administering vibration to maximize step and stance behavior in infants.

Langue : ANGLAIS