title: Correcting waveform bias using principal component analysis: Applications in multicentre motion analysis studies.
abstract: Multicentre studies are rare in three dimensional motion analyses due to challenges associated with combining waveform data from different centres. Principal component analysis (PCA) is a statistical technique that can be used to quantify variability in waveform data and identify group differences. A correction technique based on PCA is proposed that can be used in post processing to remove nuisance variation introduced by the differences between centres. Using this technique, the waveform bias that exists between the two datasets is corrected such that the means agree. No information is lost in the individual datasets, but the overall variability in the combined data is reduced. The correction is demonstrated on gait kinematics with synthesized crosstalk and on gait data from knee arthroplasty patients collected in two centres. The induced crosstalk was successfully removed from the knee joint angle data. In the second example, the removal of the nuisance variation due to the multicentre data collection allowed significant differences in implant type to be identified. This PCA-based technique can be used to correct for differences between waveform datasets in post processing and has the potential to enable multicentre motion analysis studies.
authors: Department of Mechanical and Materials Engineering, Queen's University, 130 Stuart St., Kingston, ON, Canada. Electronic address: allison.clouthier@queensu.ca.
authors: Allison L
authors: AL
authors: Clouthier
authors: Department of Surgery, University of Manitoba, 820 Sherbrook St., Winnipeg, Manitoba, Canada. Electronic address: ebohm@cjrg.ca.
authors: Eric R
authors: ER
authors: Bohm
authors: Department of Surgery, Queen's University, 76 Stuart St., Kingston, ON, Canada. Electronic address: rudanj@kgh.kari.net.
authors: John F
authors: JF
authors: Rudan
authors: Department of Physical Therapy, University of Manitoba, 771 McDermot Ave., Winnipeg, Manitoba, Canada. Electronic address: barbara.shay@umanitoba.ca.
authors: Barbara L
authors: BL
authors: Shay
authors: Department of Mechanical and Materials Engineering, Queen's University, 130 Stuart St., Kingston, ON, Canada. Electronic address: michael.rainbow@queensu.ca.
authors: Michael J
authors: MJ
authors: Rainbow
authors: Department of Mechanical and Materials Engineering, Queen's University, 130 Stuart St., Kingston, ON, Canada. Electronic address: kevin.deluzio@queensu.ca.
authors: Kevin J
authors: KJ
authors: Deluzio
mesh_terms: D000328:Adult; D000368:Aged; D015982:Bias; D001696:Biomechanical Phenomena; D003627:Data Interpretation, Statistical; D005260:Female; D005684:Gait; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008297:Male; D009864:Ontario; D025341:Principal Component Analysis
keywords: Gait; Inter-laboratory; Motion analysis; Principal component analysis; Waveform data