Driving performance in cervical dystonia

Background: Cervical Dystonia (CD) is characterized by involuntary muscle contraction of the neck and abnormal positions of the head that affects daily life activities and social life of patients. For most people, being able to drive a vehicle is a very important part of their daily life. However, it is likely that driving performance and driving safety are affected due to the involuntary muscle contractions and abnormal postures. Although Botulinum Toxin (BTX) treatment improves motor symptoms and head postures in 70-92% of CD patients, many patients still have difficulties with the execution of voluntary and controlled movements of the neck and head. Up to date, there is no literature available about driving performance and driving safety in CD patients.
Study objectives: To investigate the differences in driving performance and safety between CD patients and healthy controls in a driving simulator. To compare the subjective evaluation of the difficulty of various aspects of the driving task in subjects with CD patients and healthy controls with the Fitness To Drive Screening.
Study design: The study will be performed as an explorative case-control pilot study.
Study population: 10 subjects patients with idiopathic cervical dystonia and 10 healthy age and sex matched controls.
Primary outcomes: Driving performance, driving safety and the Fitness To Drive Screening. Driving performance is measured as the standard deviation of the lateral position in the lane, time to lane crossing, and number of lane crossings. Driving safety is measured by the number of (near) crashes and other traffic conflicts such as near crashes and rule violations.
Measurements: Measurements will be performed eight to ten weeks after BTX injections. All subjects will fill in the Fitness To Drive Screening and perform three driving tests in a driving simulator. The first test consists of a swing drive where patient drive a winding route. The second test consists of a route involving intersections and the third consists of a highway route with a merging task.
Expected results: It is expected that subjects with CD patients perform less well than healthy controls with respect to driving performance and driving safety. We expect limitations in tasks requiring movements opposite to the personal dystonic posturing of the patients.

Driving a motor vehicle is a functional task requiring a complex interaction of visual, cognitive and motor skills. A wide range of acute and chronic medical conditions may impair driving performance and safety. Since CD is characterized by involuntary movements and /or abnormal postures of the neck and head it might affect driving performance and safety.

measurements will only be performed just after the simulation drives

6 drives in a driving simulator