My mom is a permanent resident she spent most of her time
in Panama. Last time she came immigration told her the she have to
come to U.S. every 6month. Not every year like before.
Please if some body have any info. On this matter please.......
Thank you.....

Let me try to enlighten you a little bit about the residence subject. The purpose of being a "permanent resident in the U.S." is that you actually live in the U.S. Being a permanent resident of one country but living in another does mean in the U.S. that you will loose your resident status. Other questions to consider are: Does she pay taxes in the U.S.? Does she have any ties to the U.S.? If your mum wants to continue to be a U.S. resident, then I can only recommend to spend more time in the U.S. or give up the residency.