I would be interested in unpacking that statement a bit more. Does that mean all symptoms at one year are likely to remain as is? Or do some have the potential to continue to progress (some more slowly, some more quickly)? How do other variables like age, medical history, native intelligence, social support, etc. factor into the prognosis? It seems to me awfully arrogant to tell a patient (implicitly or explicitly) that once a patient hits the one-year mark, nothing is going to get better.

A friend said it took her 14+ months for all of her PCS symptoms to go away.

My doc (world-class neurosurgeon and highly experienced concussion specialist) told me at 7.5 months that recovery might take another 2-3 months, or could take another year. Given my progression to date, he said there is a very good chance I will recover to close to 100%.

Incidentally, a relative was a pioneering neurosurgeon who (among other things) worked on rehab programs for soldiers post-WWII, some of whom were initially told they would never walk again. Thanks in part to his efforts, many of them did and enjoyed greatly improved lives. Fortunately, he didn't rely exclusively on the statistics available at the time.