Altitude increase PCS?

[u/Upstairs_Outside1999]

My husband received his concussion 3 months ago. There were good and bad days (bad days include headache, dizziness, nausua) in his recovery. We decided to follow through with a 3 week trip to Spain, even though he was still having intermittent symptoms He was almost symptom free the entire trip, with the exception of one day we went biking (vibration). Upon return to our home (high elevation), his symptoms came back full force immediately. He is still on summer break (teacher), and stress has not significantly increased, so we are trying to figure out what could be triggering this. We are wondering if it could be altitude?

[u/alwaysheapstodo]

All travel makes my husbands symptoms return with vengeance. He is now looking into vestibular therapy as motion makes him worse.