Impaired heart rate variability in cervical dystonia is associated to depression.

Causes of cardiovascular autonomic dysfunction in cervical dystonia (CD) are poorly understood. Studies examining effects of botulinum neurotoxin (BoNT) therapy on heart rate variability (HRV) yielded contradictory results. There is compelling evidence that depression shifts autonomic balance towards sympathetic predominance. As depression is the most frequent non-motor symptom in CD, we sought to determine if it is associated to dysfunction of cardiovascular autonomic regulation. Standardized interviews, clinical examinations, self-rating forms, autonomic symptom questionnaire, and automated autonomic testing in outpatients with idiopathic CD were used. Cardiovascular autonomic screening encompassed five different analyses of HRV, and testing of orthostasis. 85 CD patients participated in the study. 21% of them had HRV impairment, 14% orthostatic hypotension. 30% of CD patients had symptoms of depression. In those, decreased HRV was more frequent than in CD patients without mood disturbance (40 vs. 13%; p = 0.008). CD patients with and without depression had no other significant differences, including demographics, dystonia severity, comorbidity, medication, or BoNT therapy. Cardiovascular autonomic imbalance with sympathetic predominance is a non-motor manifestation of CD, associated to depression. Impaired HRV is a cardiovascular risk factor, moreover, emphasizing the need to identify and treat depression in dystonia.