Development of an instrumented pole test for use as a gait laboratory quality check

Gait analysis is becoming an increasingly common procedure in the diagnosis of movement disorders. Core equipment includes 3D tracking cameras and force platforms. Important clinical decisions are made with the assistance of gait data, therefore it is essential to have confidence in its quality. Calibration has a major role to play here and this paper describes the development of a daily spot check pole test for use in a gait laboratory. The work develops previous such tests, by the addition of a force transducer, removing the need to assume an idealised force system and allowing amplifier gain ranges to be checked. Repeatability results are presented, along with the response to 14 simulated error modes. The test provides useful data on system performance and is able to identify and diagnose failures. Failure thresholds can be tightened as accuracy improves, particularly in the area of centre of pressure measurement. Spot checks, such as this, along with full calibration tests, will become essential as new standards are introduced into clinical practice.