These scoring systems are used in clinical studies to assess how much disease has 'progressed', although they have been criticised as not being the ideal way to accurately judge the impact of a treatment on the MS disease course. For this reason, other outcome measures are also assessed in studies.
The main scale used is the Expanded Disability Status Scale (EDSS) which was developed by Kurtzke in 1983 and measures Neurological impairment (or the damage to the functioning of the brain, optic nerves and spinal cord) in people with MS.
The EDSS score is generated following a Neurological examination carried out by a neurologist. When generating an EDSS score, the neurologist will use Functional System Scores. The Functional Systems (FS), of which there are 7, relate to various functions of the Central Nervous System such as visual functions and sensory functions. Following the examination, a score can be given for each Functional System ranging from 0 to 5 or 6 depending on the Functional System being examined. The scores are sometimes called grades. A grade of 0 (zero) relates to normal Function in the system. The higher the grade, the more problems have been detected in that Functional System.
Once a grade has been given for each Functional System the results are used,
along with other information gained from the examination, to generate the
Adapted from Kurtzke JF. Rating neurologic impairment in multiple sclerosis: an expanded disability status scale (EDSS). Neurology. 1983; 33: 1444-52.