A 48-year-old Duncan, B.C., man has been arrested for allegedly sexually assaulting a fellow patient at the Cowichan District Hospital on Vancouver Island.

An 83-year-old woman, who has dementia, was sexually assaulted after being placed in a room with two other men on Dec. 19, said Elin Bjarnason, the Vancouver Island Health Authority’s executive director of patient flow.

Bjarnason said it is against policy to place a single female in a mixed-gender room, but the hospital was forced to do so because of a bed shortage.

However, a review of the incident has led to changes in the hospital's mixed-gender policy, said Bjarnason.

"This has highlighted the need to ensure that all patients in the rooms are alert, oriented and mentally competent and able to vocalize," said Bjarnason. "Since this incident, we have added that and made our criteria more stringent for mixed-gender rooms."

Bjarnason said patients with known violent or sexually inappropriate behaviours will also be banned from mixed-gender rooms.

RCMP have not released the name of the alleged assailant, who has not yet been charged.