Improving goniometer accuracy by compensating for individual transducer characteristics

• Published in: Journal of electromyography and kinesiology Vol. 19; no. 4; pp. 704 - 709
• Main Authors: de Oliveira Sato, Tatiana, Coury, Helenice Jane Cote Gil, Hansson, Gert-Åke
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.08.2009
• Subjects: Algorithms; Arbetsmedicin och miljömedicin; Arthrometry, Articular - instrumentation; Arthrometry, Articular - methods; Crosstalk; Environmental Health and Occupational Health; Equipment Design; Equipment Failure Analysis; Gait; Goniometer; Health Sciences; Humans; Hälsovetenskap; Knee; Knee Joint - physiology; Medical and Health Sciences; Medicin och hälsovetenskap; Physical Medicine and Rehabilitation; Range of Motion, Articular - physiology; Reproducibility of Results; Sensitivity and Specificity; Transducers; Knee; Gait; Crosstalk; Goniometer
• ISSN: 1050-6411; 1873-5711; 1873-5711
• DOI: 10.1016/j.jelekin.2008.01.006

Abstract Flexible goniometers are useful for direct movement measurements. Crosstalk due to rotation between the endblocks is well known. However, even without any rotation, some crosstalk can occur. The objective of this study was to elucidate the effect of, and compensate for, the inherent crosstalk in biaxial goniometers, with specific relevance for applications with one dominating movement direction. Six biaxial goniometers (M110, Biometrics Ltd., Gwent, UK) were evaluated. A precision jig, for simulating pure flexion/extension angles, was constructed. Each sensor produced a consistent and specific crosstalk pattern, when tested over a ±100° range of motion. A procedure for correction for the inherent crosstalk of individual goniometer, based on polynomial adjust, is presented. The method for compensation, which reduced the root mean square error from, on average for the six goniometers, 3.7° (range 1.8–10.1°) to 0.35° (0.12–0.55°), might be required for obtaining valid goniometer measurements, e.g. of valgus/varus of the knee during gait flexion/extension movements.