my son is 17, and in the last six days, he has had two problems with numbness in his arm and face, and tongue, and also a little blurred vision. that was the first time. it lasted about 4 minutes. two days ago it happened again, and all the same symptoms, but this time he could not get the words out he wanted to say.. botht times he had a headache after words.. he was scared, took him to er, and they did a brain scan, and blood work, and everything turned out neg..... your thoughts