title: Motor cortex plasticity can indicate vulnerability to motor fluctuation and high L-DOPA need in drug-naïve Parkinson's disease.
abstract: Motor cortex plasticity is reported to be decreased in Parkinson's disease in studies which pooled patients in various stages of the disease. Whether the early decrease in plasticity is related to the motor signs or is linked to the future development of motor complications of treatment is unclear. The aim of the study was to test if motor cortex plasticity and its cerebellar modulation are impaired in treatment-naïve Parkinson's disease, are related to the motor signs of the disease and predict occurrence of motor complications of treatment.
  
  
  
  Twenty-nine denovo patients with Parkinson's disease were longitudinally assessed for motor complications for four years. Using transcranial magnetic stimulation, the plasticity of the motor cortex and its cerebellar modulation were measured (response to paired-associative stimulation alone or preceded by 2 active cerebellar stimulation protocols), both in the untreated state and after a single dose of L-DOPA. Twenty-six matched, healthy volunteers were tested, only without L-DOPA.
  
  
  
  Patients and healthy controls had similar proportions of responders and non-responders to plasticity induction. In the untreated state, the more efficient was the cerebellar modulation of motor cortex plasticity, the lower were the bradykinesia and rigidity scores. The extent of the individual plastic response to paired associative stimulation could indicate a vulnerability to develop early motor fluctuation but not dyskinesia.
  
  
  
  Measuring motor cortex plasticity in denovo Parkinson's disease could be a neurophysiological parameter that may help identify patients with greater propensity for early motor fluctuations.
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, India. Electronic address: asha@sctimst.ac.in.
authors.forename: Asha
authors.initials: A
authors.lastname: Kishore
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, India.
authors.forename: Praveen
authors.initials: P
authors.lastname: James
authors.affiliation: Comprehensive Care Centre for Movement Disorders, Department of Neurology, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, India.
authors.forename: Syam
authors.initials: S
authors.lastname: Krishnan
authors.affiliation: Institut du Cerveau et de la Moelle épinière (ICM), Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, Paris, France; CNRS, Centre MEG-EEG, UMR 7225, Paris, France.
authors.forename: Lydia
authors.initials: L
authors.lastname: Yahia-Cherif
authors.affiliation: Institut du Cerveau et de la Moelle épinière (ICM), Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, Paris, France.
authors.forename: Sabine
authors.initials: S
authors.lastname: Meunier
authors.affiliation: Institut du Cerveau et de la Moelle épinière (ICM), Inserm U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMRS 1127, Paris, France.
authors.forename: Traian
authors.initials: T
authors.lastname: Popa
mesh_terms: D000328:Adult; D000368:Aged; D000978:Antiparkinson Agents / Q000008:administration & dosage*; D004409:Dyskinesia, Drug-Induced / Q000175:diagnosis / Q000503:physiopathology; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000187:drug effects / Q000502:physiology*; D009473:Neuronal Plasticity / Q000187:drug effects / Q000502:physiology*; D010300:Parkinson Disease / Q000175:diagnosis / Q000188:drug therapy* / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa
keywords: Cerebellum; Motor cortex; Parkinson's disease; Plasticity; Transcranial magnetic stimulation