Article

Brain plasticity mechanisms are probably different in children but remain
poorly understood. Paired afferent stimulation (PAS) combines peripheral sensory
stimulation with transcranial magnetic stimulation (TMS) of primary motor cortex
to induce rapid, reversible, topographically specific increases in primary motor
cortex excitability suggestive of long-term potentiation in adults. Our aim was
to determine frequency, characteristics, age effects, and reproducibility of PAS
in school-age children. METHOD: Typically developing right-handed children
(6-18y) were recruited. Median nerve stimulation was delivered 25ms before
suprathreshold primary motor cortex stimulation (0.2Hz, 7.5min). Primary outcome
was changed in the amplitude of motor evoked potentials (MEPs) at five time
points after PAS (0, 15, 30, 45, 75min) expressed as area under the curve.
Reproducibility was evaluated. Secondary outcomes included stimulus response
curves and safety/tolerability. RESULTS: Of 28 children (20 males, mean age 12y),
64% demonstrated PAS effects (11 definite, seven probable). PAS effects were
sustained across all time points to 75min (p=0.004). Stimulus response curve
scores increased after PAS (n=9, p=0.02). PAS effect and age were not correlated.
PAS was highly reproducible (p=0.925, r=0.283). Tolerability was favorable
without adverse events. INTERPRETATION: PAS effects are present and reproducible
in children. Pediatric PAS paradigms appear safe and tolerable. PAS may provide
insight into endogenous developmental plasticity, informing future studies in
children with cerebral palsy and other motor disorders.
CI - (c) 2015 Mac Keith Press.

Langue : ANGLAIS