Introduction: Spasticity is a sensory-motor disorder that affects about 85% of the patients with multiple sclerosis and between 65-78% of those with spinal cord injury, among other neurological conditions. Although hypertonia is generally easy to recognise clinically, quantifying it is quite a complex matter. The large number of clinical scales that exist and their subjectivity, the discrepancy between the spasticity perceived by the patient and the clinical measurement, as well as the lack of a general correlation between the neurophysiological measures and hypertonia, all make it especially difficult, in methodological terms, to perform a valid, reliable measurement of the degree of spasticity presented by the patient.
Aims: To review the main methods of evaluating spasticity published in the scientific literature and to carry out a description and critical analysis of their advantages, shortcomings and metric properties in patients with a neurological pathology.
Development: The different methods described for evaluating spasticity are reviewed and classified in three broad groups, namely, clinical scales specifically designed for such a purpose, biomechanical tests and neurophysiological methods.
Conclusions: There is little agreement on the definition of spasticity and the need for the evaluators' training and experience when it comes to evaluating it. We recommend using a combination of the different evaluation instruments, such as the scales, biomechanical methods and neurophysiological measures reported in this study, to carry out a general diagnosis of the degree of spasticity present in the patient.