Clinical features and natural history of axial predominant adult onset primary dystonia.

The clinical features and natural history of 18 patients with adult onset axial predominant severe truncal primary dystonia are presented. The mean age of onset was 41 (42 for men, 39 for women) and there was a higher proportion of men (10:8). Analysis of their clinical features and follow up over three to five years or more showed that these patients generally conform to the characteristics of other types of adult onset primary dystonias. They tended to remain focal although there could be an initial contiguous spread, sometimes beginning in the craniocervical region and spreading axially or, rarely, vice versa. If spread occurred, involvement of the head, neck, and arms was mild in comparison with the severe dystonia of the trunk. However, in none of the patients with craniocervical or truncal onset did the dystonia spread to involve the legs. More than a third (seven of 18) of the patients had a prior history of injury at the site subsequently affected by dystonia. Treatment response to various drugs overall was poor but a third of the patients improved on treatment either with triple therapy (a combination of tetrabenazine, pimozide, and an anticholinergic drug) or high dose anticholinergic drugs alone. Severe depression occurred in 33% of patients, mainly due to the negative personal image arising from their disfiguring dystonia. None of the patients had a family history of dystonia and at the moment it is unclear whether these patients with sporadic axial dystonia are non-genetic phenocopies or are a manifestation of one or more of the genes that cause generalised dystonia or torticollis.