Influence of positional changes on spasticity of the upper extremity in poststroke hemiplegic patients

Background Spasticity commonly occurs in hemiplegic patients with stroke, and clinical experience indicates that upper limb spasticity is more apparent when patients are standing than when they are lying down. Few reports have investigated how positional changes impact the spasticity of the upper limb and trigger a combined movement called the hemiplegic posture. Objective: The objective of this study was to explore the influence of different body positions on the spasticity of the upper extremity. Methods: Eighty-four poststroke patients with upper limb spasticity were recruited for this study. We measured the spasticity of hemiplegic upper limbs involving elbow flexors, wrist flexors and digitorum flexors using the Modified Ashworth Scale (MAS), Modified Tardieu Scale (MTS) and Triple Spasticity Scale (TSS) in three positions, i.e., supine, sitting and standing. The results were obtained by comparing one position with another for each muscle. Results: All the MAS, MTS and TSS scores of all the muscles of the upper limb were significantly lower in the supine position than in the other positions (all P < 0.05), and the MTS and TSS scores were statistically higher while standing than while sitting (P < 0.05). Conclusion: High modulation of spasticity in the upper limbs measured using the MAS, MTS and TSS when transitioning to the standing position from either the supine or sitting position demonstrated that posture plays a role in modulating the spasticity of the hemiplegic upper limb in poststroke patients.