Background and purpose: There is no consensus concerning the location or severity of spasticity, or how this changes with time after stroke. The purpose was to describe: the location and severity of spasticity, in different muscle groups, during the first 1-2 weeks and at 3 and 18 months after stroke; the association between the severity of spasticity and control of voluntary movements; and the occurrence of spasticity in younger versus older patients.
Methods: In a cohort of consecutive patients, the following parameters were assessed during the first 1-2 weeks (n = 109) and at 3 (n = 95) and 18 (n = 66) months after first-ever stroke: spasticity, by the Modified Ashworth Scale in different muscle groups; plantar-flexor clonus, by physical examination; and movement function, by the Lindmark Motor Assessment Scale.
Results: During the first 1-2 weeks and at 3 months after stroke, spasticity was most common in the anti-gravity muscles. The severity of upper extremity spasticity increased over time (P < 0.05). Upper extremity spasticity and movement scores were moderately associated (r = -0.61, P < 0.05). At 3 months, spasticity was more common amongst the younger patients (P < 0.05).
Conclusions: The results confirm that spasticity is most common in the anti-gravity muscles and is associated with the control of voluntary movements. As the severity of spasticity also increased after 3 months, when neurally mediated spasticity is expected to have passed its peak, intrinsic muscle changes may play a larger role than neural components with the passage of time after stroke.