muscle weakness

my son is 14 months old and cannot sit, stand or walk and he has difficulty swallowing lumps. he is very alert, knows his name when called, is smily and looks like he would love nothing more than to be able to chase his brothers and gets frustrated because he cant.his hearing and eyesight are fine. he has a droopy right eyelid but not serious enough for surgery. he holds his own head up and can use both hands passing things from one to the other. he can hold his bottle if he is lay down but cannot hold bottle up enough to drink sitting in his chair. after months of encouragement i have taught him to roll over and back again which he started doing in the last 3/4 weeks. he is now about 12 kg. he was nearly 10 weeks premature and weighed 1676g at birth. he did his own breathing only having oxygen for a couple of hours, he was not ventilated at all and was home feeding from a bottle at 5 weeks old. he suffers quite alot from constipation.have you any ideas what could be causing these problems and any solutions please.

[Kevin Kennedy, Ph.D.]

Such developmental delay in your son's large muscle functioning demands medical evaluation. What is you son's pediatrician saying about it? Is there any family history of such difficulties? The various stages of early development in infants are reached along a spectrum of normal; it's not as if a developmental milestone is achieved by all infants at precisely the same time. And most children do not proceed at the same pace in all areas of development. Having said that, your son's physical development is far outside what could be considered the normal spectrum; that is why it invites evaluation (vs watchful waiting or patience).