title: Bradykinesia of posed smiling and voluntary movement of the lower face in Parkinson's disease.
abstract: OBJECTIVE
  Impaired facial expression, including spontaneous and emotional movements such as smiling, has been often reported in Parkinson's disease (PD). There is a general consensus that spontaneous smiling is abnormal in PD. Investigations on posed smiling yield contrasting results. Moreover, no study has yet addressed the relationship between posed smiling and abnormalities of voluntary movements of the lower face, global motor impairment and the effects of dopaminergic medication.
  
  
  METHODS
  We investigated the kinematics of posed smiling (mimicking a smile shown in a picture) and those of voluntary movements of the lower face (showing the teeth as fast as possible - voluntary grinning) in 15 patients with PD (ON and OFF therapy) and in 16 healthy controls. Facial movements were recorded using a 3D optoelectronic system and analyzed using dedicated software.
  
  
  RESULTS
  Some kinematic parameters of both posed smiling and voluntary grinning were abnormally lower in PD patients in comparison to healthy subjects. The kinematics of posed smiling correlated with those of voluntary grinning in PD patients but not in healthy controls. Posed smiling and voluntary grinning abnormalities were related to global motor severity but did not significantly improve upon L-dopa administration.
  
  
  CONCLUSIONS
  These results suggest that posed smiling and voluntary grinning are both abnormal in PD patients and that they are likely mediated by a common pathophysiological mechanism.
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Luca
authors: L
authors: Marsili
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Rocco
authors: R
authors: Agostino
authors: Neuromed Institute IRCCS, Pozzilli (Is), Italy.
authors: Matteo
authors: M
authors: Bologna
authors: Neuromed Institute IRCCS, Pozzilli (Is), Italy.
authors: Daniele
authors: D
authors: Belvisi
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy.
authors: Adalgisa
authors: A
authors: Palma
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy; Neuromed Institute IRCCS, Pozzilli (Is), Italy.
authors: Giovanni
authors: G
authors: Fabbrini
authors: Department of Neurology and Psychiatry, Sapienza University of Rome, Rome, Italy; Neuromed Institute IRCCS, Pozzilli (Is), Italy. Electronic address: alfredo.berardelli@uniroma1.it.
authors: Alfredo
authors: A
authors: Berardelli
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D005145:Face; D005260:Female; D006801:Humans; D018476:Hypokinesia / Q000209:etiology / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology*; D010300:Parkinson Disease / Q000150:complications / Q000503:physiopathology*; D012904:Smiling
keywords: Bradykinesia; Motor control; Neurophysiology; Parkinson's disease