Jumpy Baby

B
When does a baby stop the involuntary twitching?  (Arms and legs flailing)  My son is 4 and still wakes himself up constantly with the twitching.  He hates being swaddled which helps him stay asleep through the twitching.  It's a tough go at night.....he either screams and fidgets to get out of the swaddle or if we don't swaddle him he will twitch so much he doesn't stay asleep. Help?