New study findings suggest that patients with MS appear to experience a decline in mental functioning during the early stage of the disease.

To assess mental or cognitive impairments in the early stage of MS, researchers compared 21 MS patients with 22 subjects without MS. The patients with MS had experienced their first neurological symptom within two years prior to the study.

All participants underwent a series of mental functioning exams including memory and learning tests, visual/spatial functioning tests and tests of executive function, which is related to goal achieving behavior. The subjects also completed a computerized attention test to evaluate the speed and accuracy of test responses.

The results showed that compared with the healthy subjects, those with MS in the early stage of disease did perform significantly lower on each neuropsychological test with the exception of verbal short-term memory tests.

Patients with MS demonstrated a longer reaction time for simple and focused attention, impaired non-verbal memory function, and a planning deficit. The investigators also found relationships between information processing speed and disease course and employment status.

No clinically relevant depression rates were detected among the MS patients in the early stage of disease. In addition, no deficits in visual/spatial abilities were observed.

"Cognitive dysfunctions may contribute to limitation of everyday activities of patients with MS," the authors wrote.

This study was published online, ahead of print by the Journal of Neurology.