Development of a Laser Device for the Assessment of Trunk Position Sense: Normative Data and Concurrent Validation With Verticality Perception Tests in Healthy Individuals

This cross-sectional study aimed to examine the participants' ability to perceive trunk positions by comparing the trunk position sense (TPS) and subjective vertical test results. The effect of age on the perception of trunk position was also evaluated. Verticality perception was measured in the sitting position using the subjective vertical visual (SVV) bucket test and the subjective vertical postural (SVP) test with an automatic chair in the frontal plane. The repositioning accuracy of the trunk joint perception was measured using the TPS and assessed using a 3D-printed laser point support fixed to the xiphoid process during 30° of trunk lateral flexion in sitting and standing positions. Subsequently, the absolute angular deviation was calculated. The TPS data of the groups were compared using the Mann-Whitney U test. The Bland-Altman test was used to calculate the agreement between the evaluation methods. In addition, the sensitivity and specificity of the TPS_sitting, TPS_standing, and verticality tests were compared using a receiver operating characteristic curve. A total of 26 young and 26 older adults were included in this study. Older adults had a greater absolute angular deviation in the TPS_standing in the counterclockwise and total directions than the young adults. Agreement was greater between TPS_sitting and TPS_standing with SVV in young and older adults and between TPS_standing and SVP in older adults. TPS_standing has a greater sensitivity for clinical application in older adults. Therefore, the TPS is a viable instrument for assessing active trunk proprioception in young and older adults and has greater agreement with verticality tests.