CLINICAL COMPARISON OF TARDIVE AND IDIOPATHIC CERVICAL DYSTONIA

It has been suggested that tardive cervical dystonia may be clinically indistinguishable from the idiopathic form and that the diagnosis res ts solely on documenting an exposure to dopamine antagonist medication s. To investigate this, we performed a retrospective evaluation of pat ient records an 102 patients with idiopathic and 20 patients with tard ive cervical dystonia seen in our Movement Disorder Clinic over the pa st 8 years. Several clinical and demographic variables were compared a nd a number of differences were observed. The presence of extracervica l involvement, retrocollis, and spasmodic head movements were individu ally found to be predictive of tardive cervical dystonia. Torticollis, laterocollis, and trick maneuvers were predictive of idiopathic cervi cal dystonia. Head tremor (42.2%) and family history of dystonia (9.8% ) were present only in the idiopathic group. Cervical muscle hypertrop hy was significantly more common in die idiopathic group (100% versus 75%). No difference was found between the two groups in their response to treatment with botulinum toxin A. These results indicate that clin ical differences between idiopathic and tardive cervical dystonia exis t. These differences may help to distinguish them in the clinical sett ing, improve diagnostic accuracy and support the existence of a causal relationship between exposure to dopamine antagonist medications and chronic dystonia.