title: The quantification of low back disorder using motion measures. Methodology and validation.
abstract: METHODS
  Trunk angular motion features were used as a means to quantify the extent of a low back disorder in healthy people and patients with chronic low back disorders.
  
  
  OBJECTIVE
  To refine and validate a previously reported means of quantifying the extent of a low back disorder.
  
  
  BACKGROUND
  Many assessment tools of low back disorder are subjective. A quantitative assessment tool would facilitate the tracking of the recovery and help document the appropriateness of treatments.
  
  
  METHODS
  The trunk motion characteristics of 374 healthy people and 335 patients with chronic low back disorders of varying severity were documented as they flexed and extended their trunks in five different planes of motion. The trunk motion features were normalized as a function of age and gender. Four classification techniques were used to assess the ability of the quantitative motion measure to identify those with and without low back disorders. In addition, 31 patients were observed longitudinally to determine whether the motion measures agreed with observed changes in back pain symptoms.
  
  
  RESULTS
  The quantitative trunk motion measure distinguished between people with low back disorders and healthy people between 88% and 94% of the time, depending on which classification system was used. Sensitivity and specificity varied between 83% and 97%. The quantitative measure also showed promise as a means to distinguish between muscle-based and structure-based low back disorders. Prospective findings indicated that the quantification system agreed well with clinical observations of progress.
  
  
  CONCLUSIONS
  The quantification of trunk motion can serve as a measure of the extent of a low back disorder. When considered along with other clinical information, the ability to assess and treat low back disorders is enhanced.
authors.affiliation: Biodynamics Laboratory, Ohio State University, Columbus, USA.
authors.forename: W S
authors.initials: WS
authors.lastname: Marras
authors.forename: S A
authors.initials: SA
authors.lastname: Ferguson
authors.forename: P
authors.initials: P
authors.lastname: Gupta
authors.forename: S
authors.initials: S
authors.lastname: Bose
authors.forename: M
authors.initials: M
authors.lastname: Parnianpour
authors.forename: J Y
authors.initials: JY
authors.lastname: Kim
authors.forename: R R
authors.initials: RR
authors.lastname: Crowell
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D017116:Low Back Pain / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009068:Movement; D010147:Pain Measurement / Q000145:classification / Q000379:methods*; D011446:Prospective Studies; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013647:Task Performance and Analysis; D013686:Telemetry