Visuospatial functions in patients with spasmodic torticollis.

Visuospatial functions were studied in 18 patients with spasmodic torticollis and 18 matched controls. Subjects were examined with respect to their judgement of the subjective vertical, personal and extrapersonal orientation, the discrimination of left and right, the ability to judge angles and distances, and a drawing task. Patients showed marked deficits in extrapersonal orientation and atypical displacement errors to the right when requested to set the subjective vertical. Results were largely independent of the clinical characteristics of the disease. The pattern of results was attributed to a subtle attention deficit underlying complex measures of visuospatial functions. This may reflect a discrete dysfunction of the striatal-frontal circuits at least in a subgroup of patients.