Researchers at the Federal University of Bahia, Brazil have found that multiple sclerosis (MS) patients who initially had problems with vision or sphincter—a valve structure that regulates the passage of contents from one organism to another—function are at risk of severe disability. The results of their study were published in the medical journal Brain Medicine.

Researchers analyzed data from 195 patients with MS to determine how early symptoms were associated with long-term disability.

The results showed that functional deterioration was 20% more likely among patients with severe blurred vision than those without this condition.

Dysfunction of the sphincter, a violation of the qualitative nature of the activity of an organ or system—for example, the bladder or intestines—increases the probability of becoming severely disabled by 24.5%.

Also, the researchers found that acute paralysis and hypoesthesia—hypersensitivity to real, common, or even mild stimuli—were not adverse predictors of long-term prognosis.

The researchers hypothesized that the visual disturbances may indicate extensive damage to the nervous system.

But more research is needed to find out exactly why certain symptoms predict a more complex course of this disease.