WASHINGTON (AP) — Sen. Edward M. Kennedy, battling a brain tumor, walked through a wall of applause into the Senate on Wednesday and cast a stunningly unexpected vote on long-stalled Medicare legislation.

“Aye,” the 76-year-old Kennedy said in a loud voice, and he made a thumbs-up gesture as he registered his vote.

Spectators in the galleries that overhang the chamber burst into cheers - a violation of decorum that drew no complaints.

Kennedy made his way into the Senate on his own power, appearing little the worse for his illness. A patch of scalp was clearly visible amid his familiar white hair, although it was not clear whether that was a result of surgery he underwent or the effects of chemotherapy that is part of his treatment.