Multiple sclerosis (MS) is a complicated neurodegenerative disease. Although each person with MS experiences different symptoms and course of the disease, the underlying biology and the ways the disease can be measured are the same for everyone.
Disability progression
Most people with MS experience an increase in physical disability (The loss of abilities that results from damage to the central nervous system as MS progresses and may be irreversible1) at some point in time.2 When it happens, what kind of disability it is and how much it changes differs for everybody. The graphs below show how disability progression can vary between individuals.
Disability worsening related to relapse, with or without complete recovery.
Disability worsening related to relapse without complete recovery, followed by disability progression independent of relapses.
Disability progression independent of relapse.
Disease activity
In MS, the immune system attacks nerve cells in the brain, spinal cord and optic nerves.3 This disease activity can cause symptoms and disability.
There are two main types of disease activity:
Visible
Such as a relapse
(New or worsening signs and symptoms caused by inflammation in the central nervous system. These episodes develop quickly, last at least 24 hours and can continue for several days to weeks. Relapses can be followed by a full recovery or some continuing disability)4
Underlying
Detected with MRI brain scans
(Scans that show lesions or damaged areas of the brain)
Types of disability
Physical disability gets worse (progression) when disease activity causes more and more nerve cells to die (neurodegeneration).5
People may experience disability in different ways, depending on what part of the brain, spinal cord or optic nerves is affected.6
Measuring disability
Disability is measured in different ways.
Expanded Disability Status Scale (EDSS)
Measures the degree of physical disability based on a neurological exam of seven functional systems throughout the body, plus a person’s walking ability. The EDSS and its predecessor DSS have been used in nearly every MS clinical trial in the last 40 years.7
No Evidence of Progression (NEP)
A composite endpoint that measures the proportion of people with no confirmed progression of disability status (EDSS), walking speed (T25-FW) and upper extremity function (9-HPT) and may represent a new outcome for people with PPMS.
Nine-Hole Peg Test (9-HPT)
Measures arm, wrist and hand function by timing the speed in which a person can move nine pegs into nine holes and then remove them, using one hand at a time.8
Timed 25-Foot Walk (T25-FW)
Determines walking speed by measuring how fast a person with MS can walk 25 feet.9
Disease-modifying treatment
Disease activity and disability progression can occur at the earliest stage of the disease.10 So one of the goals of MS treatment is to control disease activity as early as possible.
Disability progression without treatment
Slide over to the next image to show an example of early treatment with a disease-modifying treatment (DMT)
Disability progression with DMT
Early treatment with an effective DMT may reduce disease activity and disability progression.11
References
Giovannoni, G, et al. Brain Health: Time Matters in Multiple Sclerosis. 2015; pp 14.
MS International Federation. What is MS? Available at
https://www.msif.org/about-ms/what-is-ms/ Medline Plus. Multiple Sclerosis. Available at
https://medlineplus.gov/ency/article/000737.htm National MS Society. Managing Relapses. Available at
http://www.nationalmssociety.org/Treating-MS/Managing-Relapses. De Stefano N., et al. Evidence of Axonal Damage in the Early Stages of Multiple Sclerosis and Its Relevance to Disability. Arch Neurol. 2001;58(1):65-70. Available at
http://jamanetwork.com/journals/jamaneurology/fullarticle/778355 National MS Society. MS Symptoms. Available at
http://www.nationalmssociety.org/Symptoms-Diagnosis/MS-Symptoms National MS Society. Functional Systems Score (FSS) and Expanded Disability Status Scale. Available at
http://www.nationalmssociety.org/For-Professionals/ Researchers/Resources-for-Researchers/Clinical-Study-Measures/Functional-Systems-Scores-(FSS)-and-Expanded-Disab. Accessed September 2016. National MS Society. 9-Hole Peg Test (9-HPT). Available at
http://www.nationalmssociety.org/For-Professionals/Researchers/Resources-forResearchers/Clinical-Study-Measures/9-Hole-Peg-Test-(9-HPT). Accessed September 2016. National MS Society. Timed 25-Foot Walk (T25-FW). Available at
htp://www.nationalmssociety.org/For-Professionals/Researchers/Resources-for-Researchers/Clinical-Study-Measures/Timed-25-Foot-Walk-(T25-FW). Accessed September 2016. MS Brain Health. Time Matters in Multiple Sclerosis. Available at
http://msbrainhealth.org/perch/resources/time-matters-in-ms-report-may16.pdf MS Coalition. The Use of Disease-Modifying Therapies in Multiple Sclerosis: Principles and Current Evidence. Available at
http://www.nationalmssociety.org/getmedia/5ca284d3-fc7c-4ba5-b005-ab537d495c3c/DMT_Consensus_MS_Coalition_color