Skill acquisition in people with chronic upper limb spasticity after stroke
Background: After a stroke, a considerable proportion of people experience upper limb (UL) impairments, which may affect their activities of daily living. Focal spasticity is common, for which botulinum toxin-type A (BTX-A) is used increasingly. However, published randomised controlled trials have not used valid outcome measures to assess the effects of BTX-A on spasticity and have hardly explored its impact on UL function. The primary aim of this thesis was to investigate whether task-specific UL practice in the form of an evidence-based, functional skill acquisition programme, administered after BTX-A, would have any differential effects on upper limb spasticity or functional UL activity in people more than six months after stroke. The prerequisites were to: 1) clarify the definition of "spasticity", 2) pilot a novel biomechanical spasticity measurement device, 3) standardise the assessment of arm function, 4) systematically review the literature on the effects of BTX-A and 5) compile an evidence- and theory-based skill acquisition programme. Methods: Design: randomised controlled feasibility study with four repeated measures and a blinded assessor. Fourteen participants (time after stroke: range 1.4 -11.0 years) gave informed consent and were randomised into either the experimental group (EG: BTX-A plus skill acquisition) or the placebo control group (CG: BTX-A plus inflatable arm splint). Outcome measures were: Action Research Arm Test, Canadian Occupational Performance Measure, grip force of the affected hand, Stroke Impact Scale, EMG of the elbow flexors, biomechanically measured resistance to passive movement and Ashworth scale. Outcomes were assessed at baseline and weeks 4, 7 and 13 following BTX-A injection. Differences in change between the two groups were analysed using the Mann-Whitney U-test. Applying the Bonferroni correction for three repeated measures yielded a critical p-value of 0.017. Results: At baseline, there were no significant differences between the two groups in any of the dependent variables. Compared to the CG, the EG improved in self-reported hand function between baseline and week 4 (median change 25%, range 0 to 30% vs. CG: median change 0%, range -10 to 0%; p=0.04). The EG also improved in arm function between baseline and week 7 (median ARA T change 4 points, range 1 to 8 points vs. CG: median change -1 point, range -3 to 0 points; p=0.003) as well as in self-reported ADL between baseline and week 13 (median change 11.3%, range 5 to 20% vs. CG: median change 0%, range -2.5 to 5%; p=0.02). Only the differential improvement in ARAT by the EG reached statistical significance. There were no significant differences between the two groups in any of the other outcome measures. Although the programme was perceived as intensive, most participants in the experimental group had found the intervention to be enjoyable. Conclusion: The main finding of this study was that people with severe and chronic upper limb spasticity may still improve in functional activity involving their affected arm, using a combination of BTX-A and a functional skill acquisition programme - without exacerbating spasticity. BTX-A alone did not improve upper limb activity in this study. Implications for clinical practice and research were discussed.