Ultra Sonic attack on foreign embassies?

So lately I've been reading some reports about someone in the U.S. Embassy here in Guangzhou suffering concussion like symptoms without experiencing a blow to the head. Some people claim it may be an attack on U.S. citizens (or westerners). At first I thought it was a joke, But after reading this article I believe this is happening (Not an attack on westerners or anything though) and it offers a somewhat scientific explanation for it. Still a little strange and something conspiracy theorists would love. Read the article and let me know what you think.

http://www.cbc.ca/news/thenational/national-newsletter-brain-ultrasonic-ireland-abortion-1.4672940