MS scales

Multiple sclerosis functional composite (MSFC)

Main reference: Cutter GR, Baier ML, Rudick RA, et al: Development of a multiple sclerosis functional composite as a clinical trial outcome measure. Brain 122:871–882, 1999.

Type: Clinician-rated scale.

Main indications: Used to assess the degree of disability in multiple sclerosis.

Rating performed by: Trained assessor.

Time period covered by scale: The present.

Time required to complete rating: 20–30 minutes.

Remarks: Provides a composite measure of impairment in multiple sclerosis based on three clinical dimensions of arm function (measured using the 9-Hole Peg Test), leg function ambulation (measured using a 25-foot timed walk test), and cognitive function (measured using the Paced Auditory Serial Addition Test).

These three components are assessed by objective, quantitative tests of neurological function. Developed for use in clinical trials of MS. It is more sensitive to change than the widely used but scientifically weak Expanded Disability Status Score (EDSS).

Lacks comparison with other more scientifically rigorous scales. Results are susceptible to practise effects, with scores improving with repeated testing.

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Expanded disability status scale (EDSS) (aka "Kurtzke EDSS")

Main reference: Kurtzke JF: Rating neurologic impairment in multiple sclerosis: an expanded disability status scale (EDSS). Neurology 33:1444–1452, 1983.

Type: Clinician-rated scale based on neurological history and physical examination.

Main indications: Used to determine the degree of neurological disability in patients with multiple sclerosis.

Rating performed by: Trained health professionals, most usually a neurologist.

Time period covered by scale: The present.

Time required to complete rating: 20–30 minutes.

Remarks: Widely used scale for assessing disability in multiple sclerosis clinical trials. Essentially based on a combination of ambulatory status, self-care ability, and clinical findings relating to the eight "functional systems" of the earlier Disability Status Score (pyramidal, cerebellar, brain stem, sensory, bowel and bladder, visual or optic, cerebral or mental, and other).

The EDSS gives a score from 0 (normal neurological examination) to 10 (death from multiple sclerosis), with half points from 1 upwards:

• Scores of 1.0 and 1.5 imply no disability and minimal abnormal neurological signs
• Scores of 2.0–4.5 imply increasing degrees of disability but full ambulation without aid
• Scores of 5.0–7.5 imply increasing degrees of ambulatory difficulty
• Scores of 7.5–9.5 imply bed- or chair-bound with increasing disability, especially impairment in self-care
  

Whilst the EDSS is a useful tool for communication between clinicians the many studies of its psychometric properties have consistently demonstrated that it is a poor measurement instrument unsuitable for state of the art clinical trials.

Editor's note: A further discussion of the EDSS can be found in, for example, Pryse-Philips W.  Twenty questions about multiple sclerosis clinical trials methodologies. Neurological Sciences 2001; 22 (2); 187-193.