title: Noninvasive cortical stimulation with transcranial direct current stimulation in Parkinson's disease.
abstract: Electrical stimulation of deep brain structures, such as globus pallidus and subthalamic nucleus, is widely accepted as a therapeutic tool for patients with Parkinson's disease (PD). Cortical stimulation either with epidural implanted electrodes or repetitive transcranial magnetic stimulation can be associated with motor function enhancement in PD. We aimed to study the effects of another noninvasive technique of cortical brain stimulation, transcranial direct current stimulation (tDCS), on motor function and motor-evoked potential (MEP) characteristics of PD patients. We tested tDCS using different electrode montages [anodal stimulation of primary motor cortex (M1), cathodal stimulation of M1, anodal stimulation of dorsolateral prefrontal cortex (DLPFC), and sham-stimulation] and evaluated the effects on motor function--as indexed by Unified Parkinson's Disease Rating Scale (UPDRS), simple reaction time (sRT) and Purdue Pegboard test--and on corticospinal motor excitability (MEP characteristics). All experiments were performed in a double-blinded manner. Anodal stimulation of M1 was associated with a significant improvement of motor function compared to sham-stimulation in the UPDRS (P < 0.001) and sRT (P = 0.019). This effect was not observed for cathodal stimulation of M1 or anodal stimulation of DLPFC. Furthermore, whereas anodal stimulation of M1 significantly increased MEP amplitude and area, cathodal stimulation of M1 significantly decreased them. There was a trend toward a significant correlation between motor function improvement after M1 anodal-tDCS and MEP area increase. These results confirm and extend the notion that cortical brain stimulation might improve motor function in patients with PD.
authors.affiliation: Harvard Center for Non-Invasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA. ffregni@bidmc.harvard.edu
authors.forename: Felipe
authors.initials: F
authors.lastname: Fregni
authors.forename: Paulo S
authors.initials: PS
authors.lastname: Boggio
authors.forename: Marcelo C
authors.initials: MC
authors.lastname: Santos
authors.forename: Moises
authors.initials: M
authors.lastname: Lima
authors.forename: Adriana L
authors.initials: AL
authors.lastname: Vieira
authors.forename: Sergio P
authors.initials: SP
authors.lastname: Rigonatti
authors.forename: M Teresa A
authors.initials: MT
authors.lastname: Silva
authors.forename: Egberto R
authors.initials: ER
authors.lastname: Barbosa
authors.forename: Michael A
authors.initials: MA
authors.lastname: Nitsche
authors.forename: Alvaro
authors.initials: A
authors.lastname: Pascual-Leone
mesh_terms: D000368:Aged; D000978:Antiparkinson Agents / Q000627:therapeutic use; D001931:Brain Mapping; D046690:Deep Brain Stimulation / Q000379:methods*; D004292:Dominance, Cerebral / Q000502:physiology; D004311:Double-Blind Method; D004566:Electrodes; D019054:Evoked Potentials, Motor / Q000502:physiology; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology; D009044:Motor Cortex / Q000503:physiopathology*; D009048:Motor Skills / Q000502:physiology; D009460:Neurologic Examination; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy*; D017397:Prefrontal Cortex / Q000503:physiopathology*; D013223:Statistics as Topic
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa