Diminished ventricular fluid dopamine metabolites in adult-onset dystonia.

Homovanillic acid (HVA) and 5-hydroxyindoleacetic acid (5-HIAA), the respective metabolites of dopamine and serotonin, were measured in ventricular fluid obtained from 20 patients with torsion dystonia at the time of ventriculography prior to thalamic surgery. The patients could be divided into two distinct types of dystonia--childhood-onset and adult-onset--which were identifiable on clinical and biochemical grounds. In the 14 patients with childhood-onset dystonia, the first symptom appeared in one limb in early childhood and the disease usually progressed rapidly. In the six patients with adult-onset dystonia, the first symptom usually appeared in axial muscles after adolescence and the disease progressed slowly. Ventricular fluid HVA levels were significantly lower in the patients with adult-onset dystonia than in those with childhood-onset dystonia. The differences suggest diminished dopaminergic activity, possibly secondary to nigrostriatal dysfunction, in adult-onset dystonia.