Evaluating the Progression of MS: Physical Disability
One of the dreaded words used in relation to multiple sclerosis is PROGRESSION. Much of what we do and hope for is a lack of disease progression over time. It is the reason why we incorporate disease-modifying drugs into our treatment regimen and the reason we hope to limit the occurrence of new symptoms and/or relapses.
When I think of the term progression, a musical composition comes to mind (an obvious connection for a musician to make). However, progression in multiple sclerosis is not like typical tonal progression in a musical composition. In music, chord progressions will have a resolution. There will be a cadence and a well-defined move from one chord to another. Chord progressions are found throughout the composition, many of them repeated several times.
Modulations of keys within a piece will have a point at which you are finally aware that you are no longer in the original key but a new one. When analyzing a piece of music, a modulation will prompt you to look back and ponder where the hints of the new key began and where remnants of the old key no longer appear. I think that progression in MS is more like that musical modulation. Perhaps it happens before you are even aware that it has definitely occurred.
Multiple sclerosis is a disease which affects many aspects of one's functioning: physical, cognitive, and emotional. With physical functioning, there are a variety of measurement tools which have been devised to rate the stage of progression of the patient's disability. The most commonly used tools measuring physical disability are the Functional Systems Score (FSS) and the Expanded Disability Status Score (EDSS). The FSS tool evaluates seven areas of function: pyramidal function (eg. Limb weakness), cerebellar function (eg. ataxia), brainstem function (eg. nystagmus, dysarthria, or inability of swallow or speak), sensory function (eg. mild numbness or loss of proprioception), bowel and bladder function (eg. mild hesitance, urgency, incontinence, loss of control), visual function (eg. blind spots, or impaired visual acuity), cerebral (or mental) functions (eg. mood alternation, cognitive impairment, or dementia). The EDSS combines the FSS results with degrees of dysfunction in walking ability to arrive at a score ranging from 0-10 in half-point increments.
Examples of various degrees of disability as measured on the EDSS scale:
- 0.0 - No symptoms at all
- 2.0 - Minimal disability in one functional area (eg. mild decrease in touch or pain or position sense, and/or moderate decrease in vibration in one or two limbs)
- 3.5 - Fully ambulatory (able to walk) but with moderate disability in one functional area and mild disability in one or two other areas; or two moderate disabilities; or five mild disabilities among the seven functional areas
- 5.5 - Ambulatory without aid for about 100 meters; disability severe enough to preclude full daily activities; Examples of at least one severe disability at this level would include loss of bladder function, inability to speak or swallow, dementia, or unable to perform coordinated movements due to ataxia or paraplegia
- 7.0 - Unable to walk beyond approximately 5 meters even with aid, essentially restricted to wheelchair; wheels self in standard wheelchair and transfers alone; up and about in wheelchair some 12 hours a day; usually involves more than one severe disability among the seven functional areas
- 9.0 - Helpless bed patient; can communicate and eat; usually involves moderate-severe dysfunction in most areas
There is no quick and simple test for evaluating disease progression. Repeated testing is necessary to establish a baseline and to note any increase in functional disabilities (even mild ones) over time. An official determination of disease progression is made if a patient has a persistent increase of EDSS of one point. However, even if disability is increased for over a year, it can still regress back to baseline. There is always hope and never give up.