january jane,
I have PBA and am on a treatment that is very helpful. It is called Nuedexta. Here is a link about it: Nuedexta.com. And there is a quiz on the website that helps you to determine if you have it: https://www.nuedexta.com/pba-quiz. It can cause both uncontrolled crying or laughing out of proportion to any triggers, or these can occur with no triggers at all sometimes, maybe just thoughts in your head. It may be associated with several different neurological disorders, so you shouldn't ignore it but seek medical attention.