Pop icon Janet Jackson was rushed to the hospital earlier this week while on her North American “Rock Witchu” Tour, and it appears that doctors have confirmed the cause. Rand y Jackson tells www.MichaelJacksonInsider.com that his little sister has vertigo, which is a disturbance of equilibrium that causes dizziness or the sensation of falling. “Janet is doing okay, she suffers from vertigo,” Rand y was quoted as saying. Her camp, however, has yet to release an official cause for her hospitalization Monday night just hours before a show in Montreal. Reps for the singer did say she will resume her tour on Saturday in Greensboro, North Carolina after having to postpone three dates, according to Eurweb.com. Jackson’s Monday show at Montreal’s Bell Centre was postponed when she “got suddenly ill during her sound check,” read a statement from her camp. She was rushed to Royal Victoria Hospital and released two hours later. Subsequent stops in Boston on Wednesday and Philadelphia tonight, have also been postponed. The pop icon’s tour has been rife with setbacks. Last week, Jackson called off a concert in Detroit due to “production restraints,” reports local media.