Objective assessment of cervical dystonia: a pilot study.

OBJECTIVES The aims were to characterize the movements in cervical dystonia (CD) by using an estimate of the mechanical power and work involved in the movements and to describe this through a movement energy index (MEI). MATERIALS AND METHODS The subjects (patients n = 6, controls n = 6) were seated in front of a screen with a laser pointer attached to a headband while they performed standardized movements. A three-dimensional motion capture system was used and a test-retest was performed. RESULTS The mean value of MEI was significantly higher for the patients than for the controls. There was no significant difference between MEI from test to retest for the patients but there was a significant difference between MEI from test to retest for the controls. CONCLUSION This study suggests that MEI could be a useful measure for the quantification of movement dysfunction in CD and thus an objective outcome measure in comparison of different therapies.