I am really worried. My 18 month old has started a spasm of her shoulders, sometimes neck and arms as well. It happens more often when she is tired, and when she is surprised by something- like someone new walking into the room. She had something like this when she was 6-8 months old, but it seemed to go away. In January of this year, she had both a flu, and then her 1 year jabs (but not MMR yet) and it started shortly after both events. Does anyone else have a baby around this age with this twitch? Did they grow out of it...I am getting increasingly worried. It seems to be almost daily now- about 5-10 individual spasms a day.