Fig. 2.

(A) Head Repositioning Test; (B) Head To Target Test. External black octagon: corresponds to the patients’ current maximum active cervical range of motion (ACROM); Internal grey octagon: calculation basis for training units varying between 30% and 90% of the ACROM; green line: target specification by software (globe); red line: Actual curve performed by the patient (white circle in the virtual scene) using head movements. Black arrow: required target direction respectively target position (arrowhead) as an example for Head Repositioning Test, respectively, Head To Target Test.