Cognitive dysfunction in multiple sclerosis (MS) causes numerous limitations in activities of daily living.

To develop an improved method of cognitive assessment in people with MS using novel real-world distracters.

A sample of 99 people with MS and 55 demographically matched healthy controls underwent testing with the Minimal Assessment of Cognitive Functioning in Multiple Sclerosis (MACFIMS) and a modified version of the computerized Symbol Digit Modalities Test (c-SDMT). Half of the subjects completed the c-SDMT with built-in real-world distracters and half without.

The mean time on the c-SDMT was significantly greater in MS subjects than healthy controls for both distracter (p = 0.001) and non-distracter (p < 0.001) versions. Significantly more MS subjects were impaired on the c-SDMT with distracters than the traditional SDMT (47.1% vs 30.3%, p = 0.04). There were no differences in impairment between the c-SDMT with and without distracters (47.1% vs 37.5%, p = 0.34). The distracter version had a sensitivity of 81% and specificity of 88% in detecting global cognitive impairment.

The incorporation of distracters improves the sensitivity of a validated computerized version of the SDMT relative to the non-distracter and traditional versions and offers a quick and easy means of detecting cognitive impairment in people with MS.