Assesment of spasticity : from EMG to patients' perception

Abstract

Spasticity is a common phenomenon which often develops after an upper motor neuron (UMN) lesion, such as stroke, multiple sclerosis or spinal cord injury (SCI). Spasticity can be defined as any involuntary activation of muscles as a result of disordered sensori-motor control, thus including all afferent-mediated positive features of the UMN syndrome. In patients with an UMN lesion, clinical problems of movement dysfunction arise from a complex interaction between positive features, negative features, and changes in the physical properties of muscles and other tissues. Careful assessment of all signs and symptoms that might contribute to impaired motor function in the individual patient is essential in selecting the appropriate treatment. Quantification of spasticity requires reliable and valid assessment methods. So far, there is no agreement in literature on which assessment method should be used for which purpose and in which situation. The aim of this thesis was to contribute to the development of a comprehensive set of clinically applicable measurement tools for spasticity, using clinical, neurophysiological and biomechanical measurement methods, to support clinical decision making. The chapters 2, 3 and 4 in this thesis have focused on the clinimetric value of commonly applied passive stretch tests, such as the Ashworth scale, for the assessment of spasticity. The chapters 5, 6 and 7 describe studies that investigate spasticity assessed with surface electromyography in patients with motor complete SCI, , and its association with the patients’ perception of spasticity, measured with the Visual Analogue Scale. In the final chapter the findings of the different studies are discussed and integrated, with emphasis on the implications for clinical practice.