HOUSTON (AP) — Former President George H.W. Bush is spending a fourth night in a Houston hospital where he's being treated after experiencing shortness of breath earlier this week.

Family spokesman Jim McGrath said Friday evening the 90-year-old Bush "remains in high spirits and continues to make progress."

No other details were disclosed.

Bush was taken to Houston's Methodist Hospital on Tuesday night in what was reported as a precaution. He spent nearly two months at the same hospital two years ago for treatment of a bronchitis-related cough and other issues.

Bush is the oldest living former American president. He has a form of Parkinson's disease that has forced him to rely on a motorized scooter or wheelchair.