title: Coexistence of tics and parkinsonism: evidence for non-dopaminergic mechanisms in tic pathogenesis.
abstract: We report four patients with tics since childhood who presented with typical Parkinson's disease (PD). No alteration in tics occurred before or during the development of symptoms. L-Dopa/carbidopa therapy in three patients improved parkinsonism without worsening tics over 3 months to 11 years of follow-up. Our experience fails to support hypotheses exclusively emphasizing overactivity of dopaminergic function underlying tics that would predict that PD would reduce and L-dopa exacerbate tics. This emphasizes the role of other neurotransmitter systems in the pathophysiology of tics.
authors.affiliation: Morton and Gloria Shulman Movement Disorders Centre, Department of Medicine, University of Toronto, Ontario, Canada.
authors.forename: R
authors.initials: R
authors.lastname: Kumar
authors.forename: A E
authors.initials: AE
authors.lastname: Lang
mesh_terms: D000368:Aged; D002230:Carbidopa / Q000627:therapeutic use; D004298:Dopamine / Q000502:physiology*; D004359:Drug Therapy, Combination; D005500:Follow-Up Studies; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy / Q000503:physiopathology; D013981:Tic Disorders / Q000150:complications* / Q000209:etiology / Q000503:physiopathology; D016896:Treatment Outcome
chemical_list: D007980:Levodopa; D002230:Carbidopa; D004298:Dopamine