title: Frequency and clinical correlates of retrocollis in Parkinson's disease.
abstract: OBJECTIVE
  To investigate the incidence of retrocollis and to determine its clinical correlates in patients with idiopathic Parkinson's disease (PD).
  
  
  METHODS
  Seventy-four patients with PD at Hoehn and Yahr stage 5 were examined for abnormal neck postures and were classified according to neck posture. Differences in age, age at PD onset, disease duration, years from PD onset to Hoehn and Yahr stage 5, cognitive state, the levodopa equivalent dose (LED) for dopaminergic drugs, and rigidity of the neck and upper and lower extremities were examined to determine the clinical correlates of abnormal neck posture. We also evaluated retrocollis in 356 patients with PD at Hoehn and Yahr stage 1, 2, 3, and 4 and 65 age matched normal controls.
  
  
  RESULTS
  Of the 74 patients with PD at Hoehn and Yahr stage 5 examined, 21 (28.4%) had retrocollis, 3 (4.1%) had antecollis, and 1 (1.4%) had antecollis and torticollis. Whereas, only one patient had retrocollis in PD patients at Hoehn and Yahr stage 4 and under. Patients with antecollis were significantly younger than those with normal neck posture and retrocollis. There were no differences in age at PD onset, disease duration, sex, years from PD motor symptom onset to Hoehn and Yahr stage 5, cognitive state, or LED between patients with and without abnormal neck postures. Neck rigidity scores were significantly higher in patients with retrocollis and antecollis than in those with normal neck posture.
  
  
  CONCLUSIONS
  Retrocollis is not rare in patients with PD at Hoehn and Yahr stage 5, and the incidence appeared to increase as axial rigidity increased.
authors.affiliation: Department of Neurology, Okayama Kyokuto Hospital, Kurata, Naka-ku, Okayama 703-8265, Japan. kkashi@kyokuto.or.jp
authors.forename: Kenichi
authors.initials: K
authors.lastname: Kashihara
authors.forename: Takaki
authors.initials: T
authors.lastname: Imamura
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000008:administration & dosage / Q000627:therapeutic use; D005260:Female; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000627:therapeutic use; D008297:Male; D009127:Muscle Rigidity / Q000453:epidemiology; D009333:Neck / Q000503:physiopathology; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy; D011187:Posture; D014103:Torticollis / Q000453:epidemiology* / Q000209:etiology*
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa