Posttraumatic functional movement disorders

Traumatic injury to the nervous system may account for a range of neurologic symptoms. Trauma location and severity are important determinants of the resulting symptoms. In severe head injury with structural brain abnormalities, the occurrence of trauma-induced movement disorders, most commonly hyperkinesias such as tremor and dystonia, is well recognized and its diagnosis straightforward. However, the association of minor traumatic events, which do not lead to significant persistent structural brain damage, with the onset of movement disorders is more contentious. The lack of clear clinical-neuroanatomic (or symptom lesion) correlations in these cases, the variable timing between traumatic event and symptom onset, but also the presence of unusual clinical features in a number of such patients, which overlap with signs encountered in patients with functional neurologic disorders, contribute to this controversy. The purpose of this chapter is to provide an overview of the movement disorders, most notably dystonia, that have been associated with peripheral trauma and focus on their unusual characteristics, as well as their overlap with functional neurologic disorders. We will then provide details on pathophysiologic views that relate minor peripheral injuries to the development of movement disorders and compare them to knowledge from primary organic and functional movement disorders. Finally, we will comment on the appropriate management of these disorders.