Lateralized EEG mu power during action observation and motor imagery in typically developing children and children with unilateral cerebral palsy

Objective: During motor execution (ME), mu power is diminished over the contralateral hemisphere and increased over the ipsilateral hemisphere which has been associated with cortical activation of the contralateral motor areas and inhibition of the ipsilateral motor areas respectively. The influence of action observation (AO) and motor imagery (MI) on mu power is less clear, especially in children, and remains to be studied in children with unilateral cerebral palsy (uCP). Methods: We determined mu power during ME, AO, and MI of 45 typically developing (TD) children and 15 children with uCP over both hemispheres, for each hand. Results: In TD children, over the left hemisphere mu power was lowered during ME when the right hand was used. In line, over the right hemisphere mu power was lowered when the left hand was addressed. In addition, during AO and MI increased mu power was observed when the right hand was addressed. In children with uCP, over the spared hemisphere mu power was diminished during ME when the less-affected hand was used. However, over the lesioned hemisphere, no mu changes were observed. Conclusions: The results of TD children fit the activation/inhibition model of mu power. Significance The results of children with uCP suggest that the lesioned hemisphere is unresponsive to the motor tasks