My Daughter Has Been Having Spells Of Dissyness, Slurred Speech,

My daughter has been having spells of dissyness, slurred speech, she can hear people talk to her but can't respond, her hand moves without her moving it and it feels numb. . They say she has an enlarged thyroid but all the blood tests come out fine. . They did a full blood work up and she is fine with those numbers. . Today she went into the emergency room and they put a heart monitor for 48 hours and sent her home. . Could the thyroid have anything to do with this, is there anything else she should do, and should she try exceeding or should she take it easy