Impaired Mobility in Multiple Sclerosis
although less perceptibly, in the early stages of the disease, including in patients with CIS. Since the onset of MS occurs most often between 20 and 30 years of age, when individuals are likely to be otherwise fit and leading productive lives, the loss of mobility has a more severe impact than it might if it were to develop in older persons already living a more sedate lifestyle.9–11
Figure 1: Age at Onset of Multiple Sclerosis and Age at Reaching Major Disability Scores Among 1,844 Patients with Multiple Sclerosis
As discussed above, age at onset of MS affects prognosis: in younger patients the disease generally progresses more slowly, but also leads to greater disability than does onset later in life.12
≥50
Despite the long-established recognition of mobility impairments in MS, the ability to walk is generally not sufficiently nor specifically assessed by therapists or physicians, and quantitative measures are frequently not used to determine and continuously monitor the impact of this disability on patients and their care-givers. This review aims to identify the impact of decreased walking ability on patients’ lives. An accompanying article in this issue considers the various methods used to assess both general disability and specific aspects of walking ability in MS (see pages 61–8).
Impaired Mobility Limits Activities and Social Participation – An Important Part of the Burden and Impact of Multiple Sclerosis As noted above, MS often leads to significantly impaired abilities. Recently, the International Classification of Functioning (ICF) produced by the World Health Organization (WHO) proposed terms related to disability and handicap that aim to avoid negative connotations. What used to be called ‘disability’ is now described as ‘activities’, and instead of ‘handicap’ the emphasis is on ‘participation in social life’. Core sets of terms related to MS were developed by the ICF at an International Consensus Conference following established rules. In some current and older publications, however, the former terms disability and handicap are used, and when referring to literature this article has retained the reported terminology.
The general decrease in levels of activities and social participation that accompanies the progression of MS pathology, the loss of walking ability in particular, gradually reduces a patient’s functional capacity – both in employment and in his or her private and social life. Data from studies over the past two decades show that after disease onset, the median time until a patient has some limitation in walking ability is eight years, the median time until the patient needs some support, such as a walking stick, is 20 years and the median time until the patient is confined to a wheelchair is 30 years.13
Loss
of walking ability can also negatively influence the quality of life of family members.
Various studies have highlighted the burden caused by MS, with most showing motor disability to be the most feared by patients. In recent work, walking in particular was shown to be the faculty most valued by patients and its loss was regarded as one of the worst consequences of the disease.14–16
In a survey in the UK that included
Approximately 37% with short-duration MS and 27% with long-duration MS rated walking to be the most important (see Figure 2). Surprisingly, this was greater than the numbers rating visual function (16 and 24%), thinking and memory (8 and 15%) or even lack of pain (11 and 9%) as their most important domains. On the basis of these findings, it was concluded that patient-centred scales, tailored
84 patients who had MS of a duration greater than five years and a further 82 patients with MS of a duration greater than 15 years, participants were asked to rank 13 of their faculties in order of importance.8
EUROPEAN NEUROLOGICAL REVIEW
The effects of MS symptoms, impact on QoL, costs and burden of disease were analysed in a recent literature search of clinical studies published up to January 2009.16
Results from the identified clinical
studies showed that impaired mobility was considered to be of high concern among many patients. For example, in one chosen study, a postal survey of 1,992 patients with MS in the UK, >90% of patients reported mobility as a concern and pain was reported by >80% of patients; among patients receiving disease-modifying treatments (DMTs), only 52% reported improvement in mobility.16,17
In another
study, spasticity was reported to affect the life of 44% of patients.18 The authors of the review concluded that there is a need for greater recognition of disability and its effects in MS as well as a need for targeted treatments for specific impairments to improve QoL and reduce indirect costs.16
Another literature search covering the period
1980–2008 found that, across a number of studies, the prevalence of impaired mobility ranged from 50 to >90%.15
This variability was attributed to differences in the methods employed, definitions used 57 53 57 64 70
40–49 30–39 20–29 ≤19
17 43 48 57 65 34 43 52 59 25 32 36 51 58 47 50
01020304050607080 Current age (years)
DSS = disability status scale. A score of 4 indicates limited walking ability but able to walk without aid or rest for more than 500m, a score of 6 indicates the ability to walk with unilateral support for no more than 100m without rest and a score of 7 indicates the ability to walk no more than 10m without rest while leaning against a wall or holding onto furniture for support. A given score of disability was defined as irreversible when a patient had had that score or more for at least six months, excluding any transient worsening of disability related to relapses. Source: Confavreux and Vukusic, 2006.2
to the value of these abilities, should be major outcome criteria for the assessment of any therapies in MS.
Further work highlighting the importance of walking included the Canadian Community Health Survey (CCRS), which compared a variety of health-related quality of life (HRQoL) parameters in 302 patients with MS (age range 46.6–50.8 years) with those in 109,741 individuals without MS (age range 44.7–44.8).14
HRQoL was determined using the
Health Utilities Index Mark 3 (HUI3) score based on vision, hearing, speech, walking, cognition, dexterity and pain. Among these, walking had the greatest difference relative to the general population in HUI3 score (difference 0.26; pTable 1). The magnitude of this burden was concluded to be severe relative to the general population.
Onset of multiple sclerosis Median age (years)
DSS4 DSS6 DSS7
Age at onset of multiple sclerosis (years)
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