Rocker Bret Michaels, who has been hospitalized since Thursday following a brain hemorrhage, has suffered a setback in his condition, according to his official website. Tests indicate that, as a side effect of the bleeding in his brain, Michaels is suffering from hyponatremia, an abnormally low level of sodium in the body fluids, which can lead to seizures. Michaels remains in critical but stable condition and is continuing to undergo tests. “With further testing and rehabilitation, [doctors] are hopeful that Bret will gradually improve as the blood surrounding the brain dissolves and is reabsorbed into his system, which can be a very painful recovery and take several weeks to months,” says the latest statement posted to Michaels’ website. “Michaels remains under 24-hour observation in the ICU and is in positive spirits. He is responding well to tests and treatments. Even though today was a minor setback, doctors remain hopeful for a full recovery and plan to release more specific information next Monday.”