Pathophysiology, assessment and management of multiple sclerosis spasticity: an update

Spasticity is one of the most common and disabling symptoms associated with multiple sclerosis (MS). MS spasticity occurs through both myelin and nerve fiber (axonal) degradation, which commence in the early stages of the disease. More than 80% of MS patients experienced spasticity in a large UK survey, with more than 50% of patients reporting their spasticity to be `moderate' or `severe'. Data from a large US registry show that patients with moderate-to-severe MS spasticity experience levels of disability that correlate closely with being wheelchair-bound and/or bedridden. The Ashworth scale is the most commonly used scale for assessing the degree of MS spasticity. However, the validity, reliability and sensitivity of this scale have been challenged and it is not considered an ideal scale for assessing the severity of MS spasticity. The numerical rating scale, a well-established standard pain assessment tool, provides a reliable, valid and simplified scale for patient self-rated assessment of the mean level of spasticity over the previous 24 h (0 = no spasticity, 10 = worst possible spasticity). According to data from the German MS Register, almost a third of MS patients with spasticity were untreated. Despite the availability of oral agents for generalized spasticity (often used in conjunction with physical/rehabilitation management strategies), including baclofen, tizanidine, dantrolene and gabapentin, there is limited clinical evidence to support their use and there is a need for improved and better tolerated pharmacological therapies for MS spasticity. The endocannabinoid system modulator, Sativex(®) (nabiximols, USAN name), provides an alternative therapeutic approach in the management of MS spasticity.