Coexistence of ties and parkinsonism: Evidence for non-dopaminergic mechanisms in tic pathogenesis

We report four patients with ties since childhood who presented with typical Parkinson's disease (PD). No alteration in ties occurred before or during the development of symptoms. L-Dopa/carbidopa therapy in three patients improved parkinsonism without worsening ties over 3 months to 11 years of follow-up. Our experience fails to support hypotheses exclusively emphasizing overactivity of dopaminergic function underlying ties that would predict that PD would reduce and L-dopa exacerbate ties. This emphasizes the role of other neurotransmitter systems in the pathophysiology of ties.