Neurologic Impairment in Multiple Sclerosis and the Disability Status Scale

Scales to measure disability in multiple sclerosis have been rather numerous. One system used includes the delineation of overall neurologic dysfunction according to a Disability Status Scale which is scored on a 0 to 10 basis, with 0 being normal, the numbers rising in proportion to severity of involvement, and 10 used for death due to MS. The other part of this system is the assessment of dysfunction according to Pyramidal, Cerebellar, Brain Stem, Sensory, Bowel and Bladder, Visual, Cerebral, and Other functions, each one save the last being graded 0 to 5 or 0 to 6 according to severity of involvement. Based on some 2000 examinations over the first 20 years or so of illness in 572 male MS patients, the overall frequency of involvement according to the functional systems was Pyramidal 80 per cent, Cerebellar 72 per cent, Brain Stem 69 per cent, Sensory 52 per cent, Bowel & Bladder 33 per cent, Visual 31 per cent, Cerebral (mood) 16 per cent, Cerebral (mentation) 5 per cent, and Other 21 per cent. Seizures were present in 1.4 per cent. When symptoms referable to pyramidal and cerebellar dysfunction were distributed by limbs involved, there was a tendency toward symmetry of involvement with the lowers much more often affected than the uppers. Sensory complaints were equally common for each limb or combination of limbs, but sensory findings on exam showed the same pattern as the motor and coordination complaints. When correlated with the Disability Status Scale, each of the functional systems showed not only increasing frequency but also increasing severity of involvement as overall disability increased. Involvement in each functional system was significantly correlated with involvement in each of the others, save for the Cerebral-Sensory pair, and the highest correlations for each functional system were with the Disability Status Scale. Accordingly, it is concluded that as groups of MS patients worsen, they worsen in all areas. Therefore, any measure which will reflect even a part of this worsening will appear to be a valid estimate for the course of disease in groups of patients, and all of the published scales designed to evaluate disability in MS meet this criterion. Whether one system is more “correct” than another is not amenable to proof, and the choice would seem to depend more on factors such as familiarity and ease of application of the system rather than on its intrinsic merits.