Cerebral Activity Related to Primary Motor Stereotypies in Children: An EEG Study.

Objective Motor stereotypy is a common movement disorder observed in children and adolescents but whose pathophysiology is unknown. Therefore, our overall objective is to study cerebral activity related to stereotypies. First, we want to define whether motor stereotypies are preceded by a cortical potential, as it is observed before voluntary movements. We hypothesize that no pre-movement potentials will precede the stereotypies. However, if a pre-movement potential is observed, our secondary objective is to compare this potential to cortical potentials that precede voluntary movements. We also aim to study cortical potentials preceding voluntary movements in healthy children and to compare them with the potentials observed in children with stereotypies. Study population 12 children presenting with primary motor stereotypies and 12 healthy children. Design Using 19 scalp electrodes, we will record the patients electroencephalographic (EEG) activity for up to 8 hours during one day. The electromyographic (EMG) activity of the muscles involved in the stereotypies will be recorded with surface EMG electrodes. Healthy children will undergo an EEG for 2 hours. During this EEG recording, they will be asked to perform arms movements. Outcome measures Primary outcomes: latency and amplitude of both evoked and induced activity (cortical potentials) related to motor stereotypies will be measured. Secondary outcomes: latency and amplitude of evoked and induced activity related to voluntary movements will be measured.