Combining regular memory and other cognitive tests and MRI scans may help doctors to identify which people with inactive or benign multiple sclerosis will soon develop the disabling disease, a study suggests.

Some neurologists define people who are fully functional 15 or more years after the onset of MS as having "benign" disease. It's thought that correctly identifying these people may help in treatment.

In Wednesday's online issue of the journal Neurology, researchers said a model that combined three predictors distinguished how many patients had "progressive" or worsening disease with an accuracy of 82 per cent.

"Our findings strongly suggest that a person's gender, cognitive state and amount of lesions on the brain are important factors for predicting MS progression," study author Dr. Maria Pia Amato of the University of Florence in Italy said in a release.

"Our study highlights the importance of cognitively testing people with benign MS who appear to be healthy. This information might be important in tailoring the patient's treatment."

The study looked at the cognitive test results and brain scans of 63 people — 43 women and 20 men — with benign MS over five years. Participants had neurologic exams every six months.

Nearly 30 per cent of people with benign MS significantly worsened over the course of five years.

People who failed more than two out of 10 cognitive tests were 20 per cent more likely to progress over time. The tests assessed verbal and visual memory, attention and speed of information processing, and verbal fluency.

Among the small number of men with benign MS, they were nearly three times more likely to experience later signs of MS compared to women.

People with brain lesions detected on MRI scans were also 1.3 times more likely to develop signs of the disease.

At followup, 43 patients still had benign disease, and 18 had developed significant disabilities or secondary progression.

An editorial accompanying the study called the findings important.

"If some patients with so-called benign disease course have cognitive impairment, and if cognitive impairment is a significant risk of disease progression, much more attention should be devoted to detecting and preventing such pathology in these otherwise healthy-appearing patients," Ralph Benedict of the State University of New York at Buffalo and Dr. Franz Fazekas of the Medical University of Graz, Austria, wrote.

While it's "debatable" at which point patients with benign MS should start having neuropsychological screening and monitoring of care, the findings show the importance of comprehensively evaluating patients with "a seemingly benign course," they added.

The study was limited in that it only included participants who were seen at three specialty clinics in Italy. The researchers also did not take into account use of MS drugs and not all participants had MRI scans, the team acknowledged.

The study was partly funded by the Italian Multiple Sclerosis Association and several authors reported ties to pharmaceutical companies.