title: Comparison of neck movement smoothness between patients with mechanical neck disorder and healthy volunteers using the spectral entropy method.
abstract: OBJECTIVE
  Mechanical neck disorder is one of the most common health issues. No related observations have applied spectral entropy to explore the smoothness of cervical movement. Therefore, the objectives were to ascertain whether the spectral entropy of time-series linear acceleration could extend to estimate the smoothness of cervical movement and compare the characteristics of the smoothness of cervical movement in patients with mechanical neck pain (MND) with healthy volunteers.
  
  
  METHODS
  The smoothness of cervical movement during cervical circumduction from 36 subjects (MND: n = 18, asymptomatic: n = 18) was quantified by the spectral entropy of time-series linear acceleration and other speed-dependent parameters, respectively.
  
  
  RESULTS
  Patients with MND showed significantly longer movement time, higher value in the spectral entropy and wider band response in frequency spectrum than healthy volunteers (P = 0.01).
  
  
  CONCLUSIONS
  The spectral entropy would be suitable to discriminate the smoothness of cervical movement between patients with MND with healthy volunteers and demonstrated patients with MND had significantly less smooth cervical movement.
authors.affiliation: Department of Biomedical Engineering, National Cheng-Kung University, Tainan, Taiwan.
authors.forename: Chia-Chi
authors.initials: CC
authors.lastname: Yang
authors.forename: Fong-Chin
authors.initials: FC
authors.lastname: Su
authors.forename: Lan-Yuen
authors.initials: LY
authors.lastname: Guo
mesh_terms: D000328:Adult; D001696:Biomechanical Phenomena / Q000502:physiology*; D019277:Entropy; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D009333:Neck / Q000503:physiopathology*; D013997:Time Factors; D055815:Young Adult