Hi,
we have a new forum, you may want to post your questions there:
http://discourse.libcinder.org/
If the EEG device is streaming data over TCP, it should not matter from which platform (Mac, Windows or even Linux) you connect to it, right? And JSON doesn't sound like the best format for the data. But maybe that's not something you can change.
By far the best option you have is to use
boost::asio, as it is cross platform and future proof. It's already part of Cinder, so adding it to your project should be a breeze. However, it's not the easiest library to get into and I myself have limited experience with it. You may find more help and info on the other forum.
-Paul