As Pierre said, at the beginning, rest and then gradual return to activity is good for about 90% of patients, but there is about 10% who, after two weeks, still have symptoms. There are chiropractors, physiotherapists, occupational therapists, athletic therapists—am I missing anyone, Pierre?—who all have great expertise in specific areas of concussion and know how to help people with specific problems, whether it be that they're having trouble with memory, with balance, or with their neck. They have the expertise to deal with that.
As a physician, I do not give very many complicated exercises for balance. I can give simple ones, but when you fail that first two weeks, you need something a bit more. Unless you have a private insurance plan, often that's not covered.