Introduction

Multiple sclerosis (MS) is an inflammatory, demyelinating disorder. Its prevalence varies greatly throughout the world and appears to be influenced by a complex combination of geographical location and genetic background (Skegg 1991). In the temperate zones of northern Europe, North America and Australasia prevalence rates in the region of 100/100 000 are frequently recorded, reaching 300/100 000 in the Orkney and Shetland Islands. By contrast, most of Asia and Africa have a very low prevalence in the order of 5/100000. There is a female preponderance with a male/female ratio of approximately 1–1.5. Mean age at onset is 30 years, but there is bimodal distribution with a major peak between 21 and 25 years and a lesser one at 41–45 years of age (Confavreux et al. 1980; Thompson et al. 1986). Childhood onset, although rare, is well recognized, and diagnosis has also been made in patients over 70 years of age (Noseworthy et al. 1983).

One of the hallmarks of MS is its inherent variation, which is seen within the individual patient, between patients and between groups of patients. This feature, together with an inability to predict the outcome of individual patients in terms of disability, is one of the most difficult aspects of the condition for the patient and for the development of a management plan. As MS frequently affects young adults the disability which results has a major impact on the areas of employment, family role and society, all of which have major implications in terms of resourcing and support (Inman 1984).