As first-time parents, we have identical twin 9-month olds (7 month corrected). No complications while in the NICU for 45 days (born at around 3.5 pounds), have been healthy since coming home, and have gained weight quite quickly (currently ~20 pounds).
When our twins' hands are free (such as when sitting in someone's lap, laying on their backs on the floor, or on back in the crib), they make motions with their arms and hands as if they are musical conductors -- sometimes slowly, and other times quickly. It especially is present when they seem nervous, but even when relaxed, if they are not focused on holding on to an item, their hands and arms move aimlessly like they are conducting for an orchestra.
We've asked our parents if this is "normal" baby behavior, but they "can't remember", which needless to say, makes us worry.
They are capable of directed hand movements to pick up and hold an object, and nothing seems alarming about that (they seem to have control of their hands), but it appears as though, when they aren't consciously moving their hands, they just "conduct" -- hands twist back and forth, arms flap, etc. They don't seem bothered by it or even seem to notice it. The movements are often "jerky," too. Head motions are always smooth, though, so it doesn't seem to be systemic to all muscles. During bottle feedings, these movements don't occur as much, but can, on occassion, make it difficult to feed. (Again, seems related to stress level, but it also happens when the babies do not seem stressed, such as happy excitement about getting attention.)
We read in a baby book that these motions and jerkiness are caused by connections still being made in the brain, but that they reduce and smooth down at 3 months.... but we're hoping someone else can tell us that this is normal behavior, or if they're familar with what it might be.
Do your babies' arms and hands constantly move in this sort of fashion?
Obviously, we're going to bring this up at our next pediatrician appointment, but I'd like to ask some other parents because we are starting to get a touch of paranoia. I have some video that I'm tempted to post on YouTube, but I really dislike the idea of getting medical advice from the Internet. :-)