This has been debunked for a number of years now, but like the aspartame causing "things"
it hangs on.
I will say that this statement may or may not be correct in its assumptions.
"writer and his friends would go to Chinese restaurants, they would often have a certain set of unpleasant symptoms afterward: numbness in the back and arms, palpitations, a general feeling of weakness. This wasn’t a scientific paper or a medical paper. It was a letter to the editor—which anybody can write—proposing a question. The writer was a doctor, but not a specialist in anything that would have to do with MSG chemistry. "
The writer was a neurologist in DH's class at Neurological Institute. Doesn't make it any more correct in a final analysis. It just got attention--as happens today even more on the internet.