Relationship between Passive Stretch Resistance in spastic wrist Flexors and Clinical Scales of Stroke Survivors: A Cross-sectional Study

Objective: Spasticity is a common motor dysfunction in many neurological diseases, such as stroke, cerebral palsy and Parkinson’s disease. The definition of spasticity used before excludes elasticity and viscosity caused by alterations of muscle and tissue properties. In this study, we explored components of passive movement resistance in the wrist flexor in subjects after stroke, and also investigate the correlation between these components and clinical scales such as Modified Ashworth scale(MAS) and Fugl-Meyer Assessment (FMA).Method: A cross-sectional study was performed in 15 stroke survivors. Modified Ashworth Scale and Fugl-Meyer Assessment were assessed by an experienced physical therapist. Components of passive movement resistance in the flexors of wrist and finger were recorded by NeuroFlexor (Aggro MedTech AB, Solna, Sweden), then the average resisting force in 1 second ensued the passive stretch at 5°/s was took as peak resisting force (PRF). The peak resisting force between paretic side and non-paretic side was compared. Pearson’s correlation was used to test the relation between the components and Fugl-Meyer Assessment, while Spearman’s rank correlation for Modified Ashworth scale and the components.Results: The Peak Resisting Force(PRF) of the paretic side (10.49±1.65N, mean±SD) during the slow passive stretch(5°/s) was significantly higher than the non-paretic side (8.98±1.11N, p<0.05). Correlations between MAS and the components/peak resisting force were insignificant (Table II). FMA has significant correlations with Neural Component and Elasticity Component of the paretic side (Pearson’s correlation, p<0.05).Conclusions: The higher PRF of slow passive stretch in the paretic side might be attribute to the higher muscle stiffness. Subjects with lower Neural Component or Elasticity Component of the paretic wrist correlated with FMA. These findings could be applied in clinical evaluation of functional performance of the wrist muscle of stroke survivors.