Medical, pyschological, social, and programmatic barriers to employment for people with multiple sclerosis

by Kurt L. Johnson, Dagmar Amtmann, Kathryn M. Yorkston, Estelle R. Klasner, Carrie M. Kuehn

Multiple sclerosis (MS) is a chronic, often disabling disease of the central nervous system and is the most common cause of chronic neurological disability in young adults, affecting between 250,000 and 350,000 people living in the U.S. With an average age of 28 at the time of diagnosis, MS disrupts the careers of working-aged individuals, most commonly Caucasian women from northern European backgrounds. MS typically presents with a relapsing-remitting course. However, after a period of time averaging from five to 15 years, most experience a secondary progressive phase where the course changes to either a continuously progressing one or one that progresses between exacerbations (Polman & Uitdehaag, 2000).

MS occurs through a process of progressive destruction of the "white" matter in the nervous system--the myelin sheath that protects the nerves and allows for uninterrupted transmission of nerve impulses. This progressive demyelinization is initially an inflammatory process that ultimately leads to the destruction of the nerve. The initial inflammation is called an "exacerbation" and can often be treated using medications to reduce the residual damage. MS is now thought to be an autoimmune disorder, which develops from a complex interaction of early exposure to multiple viruses and genetic vulnerability. MS is characterized by a variable and complex array of symptoms including physical, sensory, and cognitive changes. These symptoms may vary from day to day and can present challenging barriers to participating in employment (Boyden, 2000; Herndon, 2000).

Several important trends have emerged in the last decade, including changing medical management, closer examination of issues related to employment, and trends in health care systems. These trends necessitate that rehabilitation professionals revisit or update their knowledge. The purpose of this article is to provide an overview of published literature that is pertinent to the employment of people with MS.

Trends in Medical Management

The past decade has brought important changes in medical management of MS. From the perspective of the neurologist, disease management has changed "from nihilism to reasonable optimism" (Comi, Colombo, & Martinelli, 2000). This increased optimism is the result of two important trends. First, improvements in magnetic resonance imaging (MRI) techniques have led to a better understanding of the nature and course of the disease. Second, using drugs that became available during the past decade can alter the course of the disease.

MRI as a Tool for Understanding MS

MRI involves the application of a powerful magnetic field to the body that causes cell nuclei to behave like tiny magnets. The signals are picked up by a very sensitive antenna and forwarded to a computer for processing. A variety of neuro-imaging methods are now available, which when taken together, provide a detailed understanding of the neuropathology associated with MS (Joy & Johnston, 2001). When first developed, MRI helped to identify sub-clinical lesions or lesions which had not yet resulted in apparent deficits leading to earlier diagnosis. More recently, MRI has been used to track changes in the brain over time and monitor the impact of drug treatment. Figure 1 illustrates the typical clinical course of relapsing-remitting and secondary progressive MS. Also noted are clinical and sub-clinical episodes of inflammation (exacerbations) along with the progression of axonal loss over time. Neuro-imaging techniques have allowed researchers to study how lesions evolve and resolve. They have also led to the appreciation that MS is not just a disease of myelin but that over time the brain atrophies and white cell matter between the lesions of MS may also be abnormal.

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The correlation between conventional MRI and the functional status of an individual with MS has been described as "modest" (Miller, Grossman, Reingold, & McFarland, 1998). In research studies using MRI, areas of new lesions are often observed even when the individual under study is not experiencing any change in function and is considered to be in the remitting phase of the disease. These findings suggest a previously unsuspected level of activity and pathology throughout the course of the disease. In other words, the disease is active and progressive in a substantial number of individuals even during early stages of the disease when symptoms may be minimal. Miller and colleagues (1998) suggested several reasons for the lack of strong correlation between results of conventional MRI finding and level of functional disability, including problems with measurement error in quantifying MRI parameters; difficulty quantifying relapses; and the non-linearity of the Expanded Disability Status Scale (EDSS), a commonly used scale that measures both impairment and disability (Kurtzke, 1983). They (Miller et al, 1998) also suggested that MS is a very complex phenomenon in which specific aspects of the disability may not be simply or directly associated with underlying pathophysiology. Newer unconventional MRI strategies may provide a closer link between underlying pathology and clinical symptoms in MS (Matthews & Arnold, 2001).

The Emergence of Course-Altering Drugs

Until the last decade, drug management in MS has focused on relieving the symptoms of the disease, but not altering either the frequency of relapse or the rate of progression. In the 1990s, the term "disease-modifying therapy" began to emerge with the introduction of a number of drugs known as immunomodulatory agents, or the "ABC" drugs: Avonex[R], Betaseron[R], and Copaxone[R]. These drugs have been studied in carefully controlled clinical trials and have been shown to alter the clinical course of the disease by reducing the number and severity of attacks in individuals with relapsing-remitting MS (Comi, Colombo et al., 2000; Weinstock-Guttman & Jacobs, 2000). They have also been shown to alter disease features measured by MRI. When individuals taking the drugs are compared to controls, they have fewer new lesions, less brain atrophy, and reduced total burden of the disease.

The timing of intervention appears to be critical. Studies suggest the course-altering drugs are most effective in the early relapsing/remitting phase of the disease and are much less effective with progressive disease. There is a trend toward starting the drug early in an effort to prevent or reduce the early axonal damage that has been identified in MRI studies (Comi, 2000; Comi, Colombo et al., 2000). In a consensus statement, the U.S. National MS Society endorsed initiating pharmacological treatment as soon as a definite diagnosis of relapsing MS has been made ("US MS society urges early drug treatment," 1998).

Despite these encouraging advances, the drugs are costly and are not viewed as a cure for the disease. Researchers suggest that because of the heterogeneity of the myelin destruction process, no single agent will be sufficient to control the disease (Weinstock-Guttman & Jacobs, 2000). One of the medications requires self-injection, which limits the appeal for many. Side effects include flu-like symptoms (Gottber, Gardulf, & Fredrikson, 2000; Walther & Hohlfeld, 1999), and possible depression (Feinstein, 2000), which may also serve as barriers to use for some individuals.

Because it has been recognized for some time that MS disease activity is related to an autoimmune disease, medications used to suppress the proliferation of cells and cell products (antibodies) have been used to try to suppress disease (Edan, Miller, Clavet, Confavreaux, et at, 1997). Immunosuppressive drugs such as methotrexate, azathioprine, and cyclophosphamide are some of the oldest treatments for MS. In general, use of these medications has resulted in was some beneficial effects that are outweighed by negative side effects. The one exception is the more recently developed mitoxantrone (Novantrone) (Hartung, Gonsette, Konig, Kwiecinski, et al, 2002). This agent is a potent immunosuppresive medication effective in R-R and SP MS. However, it has a number of side effects including cardiotoxicity and generally cannot be used longer than a cumulative two, to two-and-a-half, lifetime years (Ghalie, Edan, Laurent, Mauch, et al, 2002).