Abnormal or altered muscle tone in the neurologically damaged patient presents major problems for restoring motor function. Many nursing interventions, such as passive limb exercises and correct limb positioning, attempt to normalise muscle tone. The effect of abnormal lone on movement can be clearly seen, therefore it may be more appropriate to measure the 'quality’ of movement. This article describes various methods of measuring muscle tone, such as video analysis, and examines the reliability of these techniques.