The CROM device has been proven to be a reliable and valid tool for HRA tests. The volunteers were seated in a chair without back support with their knees and hip joints positioned at 90 degrees, and their left shoulders pointing to the north of the room, where the measurement was made. They were also asked to wear magnetic collars so that their left shoulders always pointed north. A subject was blindfolded and seated on a chair with their head in the neutral head position (NHP), and was asked to relocate their head on the trunk as accurately as possible after cervical rotations of 30 degrees to the left and right sides. Three trials were carried out after a right head rotation and another three after a left head rotation and they were averaged for each side. The accuracy of head repositioning was measured through the absolute value of the constant error. Randomization was achieved by randomizing the measurements starting from the right or left side.

AOS PropPoint® is a practical, easy-to-use and low-cost device designed by physiotherapists to evaluate and improve the proprioceptive senses of various joints in the body. The fabric used to attach the laser apparatus to the head is made of a special veltec fabric. The laser pointer was placed at the center of the participants' atlanto-axial joint. The laser cursor was positioned at an angle of approximately 45° with the ground and projected onto a fixed semicircular horizontal target platform drawn with intervals of one degree. It was noted that the NHP and the 0° (zero point of the horizontal plane on the ground correspond to each other. The HRA measurement of AOS PropPoint® device on the horizontal platform was made simultaneously with the CROM. The deviation of the laser pointer from 0° (zero point) on the horizontal platform was recorded.

Target board was improved based on the formula tang^(-1) [error distance/90 cm]. The readings was accurate to ±0.5. We also used a target platform board with a diameter of 40 cm and graded at 1 cm intervals. The laser cursor was fixed with the help of veltec fabric in the center of the frontal bone of the volunteers. The subjects were seated 90 cm away from the frontal plane for the HRA test. When the volunteers felt that they were coming back to the starting point, the amount of deviation from the starting point was recorded by asking them to give a signal by simply extending their right index finger slightly, without opening their eye.

The CROM device has been proven to be a reliable and valid tool for HRA tests. The volunteers were seated in a chair without back support with their knees and hip joints positioned at 90 degrees, and their left shoulders pointing to the north of the room, where the measurement was made. They were also asked to wear magnetic collars so that their left shoulders always pointed north. A subject was blindfolded and seated on a chair with their head in the neutral head position (NHP), and was asked to relocate their head on the trunk as accurately as possible after cervical rotations of 30 degrees to the left and right sides. Three trials were carried out after a right head rotation and another three after a left head rotation and they were averaged for each side. The accuracy of head repositioning was measured through the absolute value of the constant error. Randomization was achieved by randomizing the measurements starting from the right or left side.