title: Hypoactivation of the primary sensorimotor cortex in de novo Parkinson's disease : a motor fMRI study under controlled conditions.
abstract: BACKGROUND
  Nuclear medicine studies in Parkinson's disease (PD) indicate that nigrostriatal damage causes a widespread cortical hypoactivity assumed to be due to reduced excitatory thalamic outflow. However, so far, functional MRI (fMRI) studies have provided controversial data about this "functional deafferentation" phenomenon. To further clarify this issue, we assessed, with fMRI, de novo drug-naive PD patients using a relatively complex motor task under strictly controlled conditions.
  
  
  METHODS
  Nineteen de novo PD patients with right-predominant or bilateral symptoms and 13 age-matched healthy volunteers performed continuous writing of "8" figures with the right-dominant hand using a MR-compatible device that enables identification of incorrectly performed tasks and measures the size and the frequency of the "8"s. The data were analyzed with FSL software and correlated with the clinical severity rated according to the Hoehn and Yahr (HY) staging system.
  
  
  RESULTS
  Fifteen (89%) of 19 PD patients and 12 (92%) of 13 controls correctly executed the task. PD patients showed significant hypoactivation of the left primary sensorimotor cortex (SM1) and cerebellum and no hyperactive areas as compared to controls. However, activation in SM1 and supplementary motor area bilaterally, in left supramarginal, parietal inferior, parietal superior and frontal superior gyri as well as in right parietal superior and angular gyri paralleled increasing disease severity as assessed with the HY stage.
  
  
  CONCLUSIONS
  In line with the "deafferentation hypothesis", fMRI demonstrates hypoactivation of the SM1 in the early clinical stage of PD.
authors.affiliation: Division of Radiology, Versilia Hospital, AUSL Versilia, Lido di Camaiore (LU), Camaiore, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Tessa
authors.forename: Claudio
authors.initials: C
authors.lastname: Lucetti
authors.forename: Stefano
authors.initials: S
authors.lastname: Diciotti
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Paoli
authors.forename: Paolo
authors.initials: P
authors.lastname: Cecchi
authors.forename: Marco
authors.initials: M
authors.lastname: Giannelli
authors.forename: Filippo
authors.initials: F
authors.lastname: Baldacci
authors.forename: Andrea
authors.initials: A
authors.lastname: Ginestroni
authors.forename: Claudio
authors.initials: C
authors.lastname: Vignali
authors.forename: Mario
authors.initials: M
authors.lastname: Mascalchi
authors.forename: Ubaldo
authors.initials: U
authors.lastname: Bonuccelli
mesh_terms: D000368:Aged; D016022:Case-Control Studies; D016009:Chi-Square Distribution; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009044:Motor Cortex / Q000503:physiopathology*; D010300:Parkinson Disease / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology*; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric