Some children briefly jerk – usually their hands and feet – while sleeping. If it only happens when they are asleep and they are otherwise growing and developing normally they need no investigations and no medications. YouTube has a good video of a child with sleep myoclonus: http://www.youtube.com/watch?v=Id5fXEKaA8M&feature=related.
Newborn babies sometimes worry their parents with similar myoclonic (jerking) movements but again, as long as it only happens in sleep, it is benign (not dangerous) and they will grow out of it (about 60% have grown out of it by 4 months of age). Multiple investigations only worry the family more and anti-epileptic medications may make the movements worse. Again, there is a nice video on youTube: http://www.youtube.com/watch?v=7z2FXVtxgaI. I have struggled to find some suitable parent information leaflets on this but if you want to read something medical about it, try this recent comprehensive review article.
Babies and children who have unusual movements while awake or who are not developing as one might expect for their age do need to see their GP or paediatrician.
Thank you for all the interest in this post. I have had lots of comments and queries from parents about their child’s twitching habits. Please note that I cannot answer individual queries on this site. You do need to see your GP or a paediatrician if you have concerns. If you want to make a private appointment to see me, please contact Highgate Hospital or Spire Roding Hospital directly. (Added 24/4/16)