title: Increased cortical excitability with longer duration of Parkinson's disease as evaluated by transcranial magnetic stimulation.
abstract: Transcranial Magnetic Stimulation (TMS) was used to evaluate the cortical excitability and central motor pathways in Parkinson's disease (PD) and correlate with severity and duration of disease. 19 cases of PD and 13 controls were enrolled. The threshold intensity (TI), cortical latency (CL), central conduction time (CCT), motor evoked potential amplitude (MEP) obtained with TMS were correlated with Hoehn and Yahr and duration of disease. The threshold intensity (TI) was significantly lower in patients of PD than controls. The TI in patients with PD was 53.16-/+8.4% patients and 67.1-/+21.6% in controls (p<0.05). This strongly correlated with duration of disease, TI being lower in patients with disease duration more than 5 years. There was no difference in the other TMS parameters - CL, CCT, MEP between patients and controls. Our study revealed increased excitability in PD which was related to longer duration of disease.
authors.affiliation: Department of Neurology, Neurosciences Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi-110 029, India. manvirbhatia@hotmail.com
authors.forename: M
authors.initials: M
authors.lastname: Bhatia
authors.forename: S
authors.initials: S
authors.lastname: Johri
authors.forename: M
authors.initials: M
authors.lastname: Behari
mesh_terms: D000368:Aged; D002540:Cerebral Cortex / Q000503:physiopathology*; D004558:Electric Stimulation; D006801:Humans; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000503:physiopathology*; D012720:Severity of Illness Index; D050781:Transcranial Magnetic Stimulation