title: Corticomotor excitability in drug-naive patients with Parkinson disease.
abstract: OBJECTIVE
  This study aimed to assess the indices of corticomotor excitability (CE) in drug-naive Parkinson disease (PD) patients and to investigate its relationship with asymmetry and severity of clinical symptoms.
  
  
  METHODS
  Eleven (4 men) drug-naive PD patients (mean age: 53.1 ± 9.8 years) and 13 (7 men) healthy controls (mean age: 51.7 ± 4.2 years) were included. All PD patients were rated on the motor section of the Unified Parkinson's Disease Rating Scale (UPDRS) with measurement of the side-specific score separately for arms and legs. Resting motor threshold (RMT), central silent period (CSP), amplitude of motor evoked potential (MEP) and central motor conduction time (CMCT) evoked by a single pulse of the transcranial magnetic stimulation were recorded in all subjects from the left and right abductor digiti minimi (ADM) and extensor digitorum brevis (EDB).
  
  
  RESULTS
  Parkinson disease patients showed higher MEP (1.8 ± 0.9 vs. 1.1 ± 0.8 mV, p < 0.05) and shorter CMCT (6.1 ± 0.9 vs. 7.4 ± 1.0 ms, p < 0.05) recorded from the ADM on the more affected side. CSP recorded from the more affected ADM was under the normal range in five and from the less affected ADM in four PD patients. For CSP recorded from the EDB, respective values are four for the more affected side and three for the less affected side. The rigidity from the more affected arm and leg correlated negatively with the respective CSP recorded from the ADM (r = -0.74, p < 0.01) and EDB (r = -0.68, p < 0.04).
  
  
  CONCLUSIONS
  In the early stage of untreated PD the CE parameters are altered only on the more affected side. The shortening of CSP reflects the severity of rigidity on the more affected side.
authors: MiroDepartment of Clinical Neurophysiology, Institute of Psychiatry and Neurology, Sobieskiego Street 9, 02-957 Warsaw, Poland. mderejko@yahoo.com
authors: Mirosława
authors: M
authors: Derejko
authors: Maria
authors: M
authors: Rakowicz
authors: Jakub
authors: J
authors: Antczak
authors: Ewa
authors: E
authors: Inglot
authors: Maria
authors: M
authors: Niewiadomska
mesh_terms: D000328:Adult; D000368:Aged; D001132:Arm / Q000503:physiopathology; D019054:Evoked Potentials, Motor; D020233:Gait Disorders, Neurologic / Q000503:physiopathology; D006801:Humans; D007866:Leg / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D009431:Neural Conduction; D010300:Parkinson Disease / Q000145:classification / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation