title: Normal motor adaptation in cervical dystonia: a fundamental cerebellar computation is intact.
abstract: The potential role of the cerebellum in the pathophysiology of dystonia has become a focus of recent research. However, direct evidence for a cerebellar contribution in humans with dystonia is difficult to obtain. We examined motor adaptation, a test of cerebellar function, in 20 subjects with primary cervical dystonia and an equal number of aged matched controls. Adaptation to both visuomotor (distorting visual feedback by 30°) and forcefield (applying a velocity-dependent force) conditions were tested. Our hypothesis was that cerebellar abnormalities observed in dystonia research would translate into deficits of cerebellar adaptation. We also examined the relationship between adaptation and dystonic head tremor as many primary tremor models implicate the cerebellothalamocortical network which is specifically tested by this motor paradigm. Rates of adaptation (learning) in cervical dystonia were identical to healthy controls in both visuomotor and forcefield tasks. Furthermore, the ability to adapt was not clearly related to clinical features of dystonic head tremor. We have shown that a key motor control function of the cerebellum is intact in the most common form of primary dystonia. These results have important implications for current anatomical models of the pathophysiology of dystonia. It is important to attempt to progress from general statements that implicate the cerebellum to a more specific evidence-based model. The role of the cerebellum in this enigmatic disease perhaps remains to be proven.
authors.affiliation: Sobell Department for Motor Neuroscience, UCL Institute of Neurology, 33 Queen Square, London, WC1N 3BG, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Sadnicka
authors.forename: Bansi
authors.initials: B
authors.lastname: Patani
authors.forename: Tabish A
authors.initials: TA
authors.lastname: Saifee
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Kassavetis
authors.forename: Isabel
authors.initials: I
authors.lastname: Pareés
authors.forename: Prasad
authors.initials: P
authors.lastname: Korlipara
authors.forename: Kailash P
authors.initials: KP
authors.lastname: Bhatia
authors.forename: John C
authors.initials: JC
authors.lastname: Rothwell
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Galea
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Edwards
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000223:Adaptation, Psychological / Q000502:physiology*; D000328:Adult; D000368:Aged; D001132:Arm / Q000503:physiopathology; D001696:Biomechanical Phenomena; D002531:Cerebellum / Q000503:physiopathology*; D004421:Dystonia / Q000151:congenital; D006257:Head / Q000503:physiopathology; D006801:Humans; D007858:Learning / Q000502:physiology; D008875:Middle Aged; D009483:Neuropsychological Tests; D010812:Physical Stimulation; D011597:Psychomotor Performance / Q000502:physiology*; D012371:Robotics; D012720:Severity of Illness Index; D014103:Torticollis / Q000151:congenital* / Q000503:physiopathology / Q000523:psychology; D014202:Tremor / Q000503:physiopathology; D014796:Visual Perception / Q000502:physiology